SI2400-BS_技术文档

Si2400

V.22BIS ISOMODEM® WITH INTEGRATED GLOBAL DAA

Features

Data Modem Formats

z 2400 bps: V.22bis

Integrated DAA

Si2400

z Capacitive Isolation

z 1200 bps: V.22, V.23, Bell 212A

z 300 bps: V.21, Bell 103

z Parallel Phone Detect

z Globally Compliant Line Interface

z Overcurrent Detection

z Fast Connect and V.23 Reversing

z SIA and other security protocols

Caller ID Detection and Decode

DTMF Tone Gen./Detection

3.3 V or 5.0 V Power

UART with Flow Control

Si3015

AT Command Set Support

Integrated Voice Codec

PCM Data Pass-Through Mode

HDLC Framing in Hardware

Call Progress Support

Ordering Information

See page 90.

Pb-Free/RoHS-Compliant

Packages Available

Pin Assignments

Si2400

Applications

Set Top Boxes

Power Meters

Security Systems Medical Monitoring

ATM Terminals Point-of-Sale

XTALI

EOFR/GPIO1

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

XTALO

CD/AIN/GPIO2

ESC/GPIO3

ISOB

CLKOUT

V

D

Description

RXD*

TXD*

GND

C1A

The Si2400 ISOmodem® is a complete modem chipset with integrated

direct access arrangement (DAA) that provides a programmable line

interface to meet global telephone line requirements. Available in two 16-

pin small outline (SOIC) packages, it eliminates the need for a separate

DSP data pump, modem controller, analog front end (AFE), isolation

transformer, relays, opto-isolators, 2- to 4-wire hybrid, and voice codec.

The Si2400 is ideal for embedded modem applications due to its small

board space, low power consumption, and global compliance.

CTS

ALERT/GPIO4

AOUT

RESET

Si3015

QE2

DCT

IGND

C1B

FILT2

FILT

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

RX

REXT

REXT2

REF

Functional Block Diagram

RNG1

RNG2

QB

Si2400

Si3015

VREG2

VREG

QE

RXD

TXD

RX

μ

Controller

(AT Decoder

Call Progress)

FILT

FILT2

REF

Hybrid

and

DC

Patents pending

RESET

DCT

Termination

VREG

VREG2

REXT

EOFR/GPIO1

CD/AIN/GPIO2

ESC/GPIO3

ALERT/GPIO4

CTS

DSP

(Data Pump)

REXT2

Control

Interface

RNG1

RNG2

QB

QE

QE2

Ring Detect

Off-Hook

Audio

Codec

CLKOUT

XTALI

Clock

Interface

XTALO

AOUT

Rev. 1.3 8/06

Si2400

2

Rev. 1.3

Si2400

TABLE OF CONTENTS

Section

Page

1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

2. Typical Application Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

3. Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

4. Analog Input/Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

5. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

5.1. Digital Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

5.2. Configurations and Data Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

5.3. Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

5.4. Global DAA Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

5.5. Parallel Phone Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

5.6. Loop Current Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

5.7. Carrier Detect/Loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

5.8. Overcurrent Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

5.9. Caller ID Decoding Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

5.10. Tone Generation and Tone Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

5.11. PCM Data Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

5.12. Analog Codec . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

5.13. V.23 Operation/V.23 Reversing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

5.14. V.42 HDLC Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

5.15. Fast Connect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

5.16. Clock Generation Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

6. AT Command Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

6.1. Command Line Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

6.2. < CR > End Of Line Character . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

6.3. AT Command Set Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

6.4. S-Register Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

6.5. Alarm Industry AT Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

6.6. Modem Result Codes and Call Progress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

7. Low Level DSP Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

7.1. DSP Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

7.2. Call Progress Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

8. S Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

Appendix A—DAA Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78

Appendix B—Typical Modem Applications Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . .84

Appendix C—UL1950 3rd Edition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85

9. Pin Descriptions: Si2400 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86

10. Pin Descriptions: Si3015 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88

11. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90

12. Package Outline: 16-Pin SOIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91

Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92

Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94

Rev. 1.3

3

Si2400

1. Electrical Specifications

Table 1. Recommended Operating Conditions

1

2

Symbol

Test Condition

Typ

Unit

Parameter

Min

Max

70

Ambient Temperature

Si2400 Supply Voltage, Digital

Notes:

T

K-Grade

B-Grade

0

25

°C

V

A

T

–40

3.0

85

A

3

V

3.3/5.0

5.25

D

1. The Si2400 specifications are guaranteed when the typical application circuit (including component tolerance) and any

Si2400 and any Si3015 are used. See Figure 3 on page 10 for a typical application circuit.

2. All minimum and maximum specifications are guaranteed and apply across the recommended operating conditions. Typical

values apply at nominal supply voltages and an operating temperature of 25 °C unless otherwise stated.

3. The digital supply, V , can operate from either 3.3 V or 5.0 V. The Si2400 interface supports 3.3 V logic when operating

D

from 3.3 V. The 3.3 V operation applies to both the serial port and the digital signals CTS, CLKOUT, GPIO1–4, and RESET.

4

Rev. 1.3

Si2400

Table 2. Loop Characteristics

(V_D= 3.0 to 5.25 V, T_A= 0 to 70°C for K-Grade and –40 to 85°C for B-Grade, See Figure 1)

Parameter

Symbol

Test Condition

Min

Typ

Max

Unit

1

DC Termination Voltage

V

I = 20 mA, ACT = 1

—

7.5

14.5

40

V

TR

L

b

DCT = 11 (CTR21)

b

DC Termination Voltage

I = 42 mA, ACT = 1

DCT = 11 (CTR21)

—

40

—

9

—

V

L

b

I = 50 mA, ACT = 1

DCT = 11 (CTR21)

L

b

I = 60 mA, ACT = 1

DCT = 11 (CTR21)

—

L

b

I = 20 mA, ACT = 0

DCT = 01 (Japan)

6.0

—

L

b

I = 100 mA, ACT = 0

DCT = 01 (Japan)

L

b

I = 20 mA, ACT = 0

DCT = 10 (FCC)

—

9

7.5

—

L

b

I = 100 mA, ACT = 0

L

b

DCT = 10 (FCC)

b

I = 15 mA, ACT = 0

—

5.2

L

b

DCT = 00

b

(Low Voltage)

2

On Hook Leakage Current

Operating Loop Current

I

V

= –48V

—

13

—

7

120

60

7

µA

mA

µA

LK

LP

TR

FCC/Japan Modes

CTR21 Mode

2

DC Ring Current

DC current flowing

through ring detection

circuitry

3

Ring Detect Voltage

V

RT = 0

11

17

15

—

22

33

68

0.2

V

RD

b

RMS

3

Ring Detect Voltage

RT = 1

V

4

Ring Frequency

F

Hz

R

5

Ringer Equivalence Number

REN

Notes:

1. SF[4] (ACT); SF5[3:2] (DCT); SF5[0] (RT).

2. R25 and R26 installed.

3. The ring signal is guaranteed to not be detected below the minimum. The ring signal is guaranteed to be detected

above the maximum.

4. The Si2400 ring detector can be programmed to detect rings between this range.

5. C15, R14, Z2, and Z3 not installed. SF5[1] (RZ) = 0 . See "Ringer Impedance" on page 80.

b

Rev. 1.3

5

Si2400

Table 3. DC Characteristics¹

(V_D= 4.75 to 5.25 V, T_A= 0 to 70°C for K-Grade, T_A= –40 to 85°C for B-Grade)

Parameter

Symbol Test Condition

Min

Typ

Max

Unit

High Level Input Voltage

Low Level Input Voltage

V

2.1

—

10

28

16

10

12

—

0.8

—

V

IH

V

IL

High Level Output Voltage

Low Level Output Voltage

Low Level Output Voltage, GPIO1–4

Input Leakage Current

V

I = –2 mA

2.4

—

V

OH

O

V

I = 2 mA

0.4

0.6

10

—

V

OL

O

I = 20 mA

—

V

O

I

–10

—

µA

mA

µA

L

2

CTS Leakage to Ground

I

CL

3

Power Supply Current, Digital

I

V pin

—

32

19

11

D

3

Power Supply Current, DSP Power Down

V pin

—

D

Power Supply Current, Wake-On-Ring (ATZ)

Power Supply Current, Total Power Down

V pin

—

D

V pin

—

15

D

1. Measurements are taken with inputs at rails and no loads on outputs.

2. Must be met in order to avoid putting the Si2400 into factory test mode.

3. Specifications assume SE1[7:6] (MCKR) = 00_b(default). Typical value is 4 mA lower when MCKR = 01b and 6 mA

lower when MCKR = 10_b.

Table 4. DC Characteristics¹

(V_D= 3.0 to 3.6 V, T_A= 0 to 70°C for K-Grade, T_A= –40 to 85°C for B-Grade)

Parameter

Symbol Test Condition

Min

Typ

Max

Unit

High Level Input Voltage

Low Level Input Voltage

V

2.1

—

3

—

0.8

—

V

IH

V

IL

High Level Output Voltage

Low Level Output Voltage

Low Level Output Voltage, GPIO1–4

Input Leakage Current

V

I = –2 mA

2.4

—

V

OH

O

V

I = 2 mA

0.35

0.6

10

—

V

OL

O

I = 15 mA

—

V

O

I

–10

—

µA

mA

µA

L

2

CTS Leakage to Ground

I

CL

3

Power Supply Current, Digital

I

V pin

—

15

9

21

14

8

D

3

Power Supply Current, DSP Power Down

Power Supply Current, Wake-On-Ring

V pin

—

D

V pin

—

5

D

Power Supply Current, Total Power Down

V pin

—

10

12

D

1. Measurements are taken with inputs at rails and no loads on outputs.

2. Must be met in order to avoid putting the Si2400 into factory test mode.

3. Specifications assume SE1[7:6] (MCKR) = 00_b(default). Typical value is 4 mA lower when MCKR = 01_band 6 mA

lower when MCKR = 10_b.

6

Rev. 1.3

Si2400

TIP

+

600 Ω

10 μF

Si3015

V_TR

I_L

–

RING

Figure 1. Test Circuit for Loop Characteristics

Table 5. AC Characteristics

(V_D= 3.0 to 3.6 V, or 4.75 to 5.25 V, T_A= 0 to 70°C for K-Grade, T_A= –40 to 85°C for B-Grade)

Parameter

Symbol

Test Condition

Min

Typ

Max

Unit

Sample Rate

Fs

—

9.6

4.9152

5

—

KHz

MHz

Hz

Crystal Oscillator Frequency

Transmit Frequency Response

Receive Frequency Response

F

XTL

Low –3 dBFS Corner

FULL = 0 (–1 dBm)

5

Hz

1

Transmit Full Scale Level

V

1

V

FS

PEAK

2

FULL = 1 (+3.2 dBm)

FULL = 0 (–1 dBm)

FULL = 1 (+3.2 dBm)

1.58

1

V

1

Receive Full Scale Level

V

2

1.58

82

PEAK

3,4,5

6

Dynamic Range

DR

ACT = 0 , DCT = 10

dB

b

(FCC) I =100 mA

L

3,4,7

Dynamic Range

ACT = 0 , DCT = 01

—

91

83

—

dB

b

(Japan) I = 20 mA

L

3,4,5

Dynamic Range

DR

ACT = 1 , DCT = 11

84

b

(CTR21) I = 60 mA

L

Transmit Total Harmonic

THD

ACT = 0 , DCT = 10 (FCC)

–85

–76

–74

–82

120

b

5,8

Distortion

I = 100 mA

L

Transmit Total Harmonic

ACT = 0 , DCT = 01

b

6,8

Distortion

(Japan) I = 20 mA

L

Receive Total Harmonic

ACT = 0 , DCT = 01

b

7,8

Distortion

(Japan) I = 20 mA

L

Receive Total Harmonic

ACT = 1 , DCT = 11

b

5,8

Distortion

(CTR21) I = 60 mA

L

Caller ID 60 Hz Common Mode

V

> 60 dB line balance at

60 Hz

V

CM

PEAK

9

Tolerance

Notes:

1. Measured at TIP and RING with 600 Ω termination at 1 kHz.

2. R2 should be changed to a 243 Ω resistor when the SF5[7] (FULL) = 1 .

b

3. DR = 20 x log |Vin| + 20 x log (RMS signal/RMS noise).

4. Measurement is 300 to 3400 Hz. Applies to both transmit and receive paths.

5. Vin = 1 kHz, –3 dBFS, Fs = 10300 Hz.

6. ACT = SF5[4]; DCT = SF5[3:2].

7. Vin = 1 kHz, –6 dBFS, Fs = 10300 Hz.

8. THD = 20 x log (RMS distortion/RMS signal).

9. V_CMcan be improved to 120 V_rmsminimum by placing a 20 MΩ resistor across the C9 capacitor.

Rev. 1.3

7

Si2400

Table 6. Voice Codec AC Characteristics

(V_D= 3.0 to 3.6 V or 4.75 to 5.25 V, T_A= 0 to 70°C for K-Grade, T_A= –40 to 85°C for B-Grade)

Parameter

Symbol

Test Condition

Min

Typ

Max

Unit

AOUT Dynamic Range, APO = 0

AOUT THD, APO = 0

VIN = 1 kHz

—

40

—

dB

–40

z

AOUT Full Scale Level, APO = 0

AOUT Mute Level, APO = 0

AOUT Dynamic Range, APO = 1,

0.7 V

V

PP

DD

60

65

dB

VIN = 1 kHz, –3 dB

V = 4.75 to 5.25 V

D

AOUT Dynamic Range, APO = 1,

—

65

—

dB

V = 3 to 3.6 V

D

AOUT THD, APO = 1, V = 4.75 to

–60

D

5.25 V

AOUT THD, APO = 1, V = 3 to 3.6 V

—

10

—

–60

1.5

–65

—

20

—

D

AOUT Full Scale Level, APO = 1

AOUT Mute Level, APO = 1

V

PP

dB

AOUT Resistive Loading, APO = 1

AOUT Capacitive Loading, APO = 1

kΩ

pF

dB

—

AIN Dynamic Range, V = 4.75 to

VIN = 1 kHz, –3 dB

65

D

5.25 V

AIN Dynamic Range, V = 3 to 3.6 V

VIN = 1 kHz, –3 dB

—

65

—

dB

D

AIN THD, V = 4.75 to 5.25 V

–60

2.8

D

AIN THD, V = 3 to 3.6 V

D

*

AIN Full Scale Level

V

PP

*Note: Receive full scale level will produce –0.9 dBFS at RXD.

Table 7. Absolute Maximum Ratings

Parameter

Symbol

Value

Unit

DC Supply Voltage

V

I

–0.5 to 6.0

±10

V

μA

V

D

Input Current, Si2400 Digital Input Pins

Digital Input Voltage

IN

V

–0.3 to (V + 0.3)

IND

D

Operating Temperature Range—B-Grade

Operating Temperature Range—K-Grade

Storage Temperature Range

T

–50 to 95

–10 to 80

–40 to 150

°C

A

T

A

T

STG

Note: Permanent device damage may occur if the above Absolute Maximum Ratings are exceeded. Functional operation

should be restricted to the conditions as specified in the operational sections of this data sheet. Exposure to absolute

maximum rating conditions for extended periods may affect device reliability.

8

Rev. 1.3

Si2400

Table 8. Switching Characteristics

(V_D= 3.0 to 3.6 V or 4.75 to 5.25 V, T_A= 0 to 70°C for K-Grade, T_A= –40 to 85°C for B-Grade)

Parameter

Symbol

Min

2.4576

–1

Typ

—

Max

39.3216

1

Unit

MHz

%

CLKOUT Output Clock Frequency

Baud Rate Accuracy

Start Bit ↓ to CTS ↑

CTS ↓ Active to Start Bit↓

RESET ↓ to RESET ↑

RESET ↑ Rise Time

RESET ↑ to TXD ↓

t

—

bd

z

t

—

1/(2 Baud Rate)

—

ns

sbc

csb

10

—

ns

t

5.0

—

ms

ns

rs

t

100

—

rs2

rs3

3

ms

Note: All timing is referenced to the 50% level of the waveform. Input test levels are V_IH= V_D– 0.4 V, V_IL= 0.4 V

Receive Timing

RXD

8-Bit Data

Mode (Default)

Start

D0

D1

D2

D3

D4

D5

D6

D7

Stop

D8

RXD

9-Bit Data

Mode

Stop

Transmit Timing

TXD

8-Bit Data

Mode (Default)

Start

D0

D1

D2

D3

D4

D5

D6

D7

Stop

D8

TXD

9-Bit Data

Mode

D2

D3

D4

Stop

t_csb

t_sbc

CTS

Note: Baud rates (programmed through register SE0) are as follows: 300,1200, 2400, 9600, 19200,

230400, 245760, and 307200 Hz.

Figure 2. Asynchronous UART Serial Interface Timing Diagram

Rev. 1.3

9

Si2400

2. Typical Application Schematic

6

R 1

7

9

R 1

+

5

R 1

R 7

R 8

10

Rev. 1.3

Si2400

3. Bill of Materials

Component

Value

Suppliers

1

C1,C4

150 pF, 3 kV, X7R,±20%

0.22 µF, 16 V, X7R, ±20%

0.1 µF, 50 V, Elec/Tant, ±20%

0.1 µF, 16 V, X7R, ±20%

560 pF, 250 V, X7R, ±20%

22 nF, 250 V, X7R, ±20%

1.0 µF, 16 V, Elec/Tant, ±20%

Novacap, Venkel, Johanson, Murata, Panasonic

Venkel, Johanson, Murata, Panasonic

Novacap, Venkel, Johanson, Murata

C3,C13

2

C5

C6,C10,C16

3

C7,C8

Novacap, Venkel, Johanson, Murata, Panasonic

Venkel, Panasonic

C9

C12

2

C14

0.68 µF, 16 V, X7R/Elec/Tant,

±20%

Novacap, Venkel, AUX, Murata, Panasonic

3

C18,C19

3.9 nF, 16 V, X7R, ±20%

0.01 µF, 16 V, X7R, ±20%

1800 pF, 50 V, X7R, ±20%

1000 pF, 3 kV, X7R, ±10%

33 pF, 16 V, NPO, ±5%

10 pF, 16 V, NPO, ±10%

47 pF, 16 V, X7R, ±10%

Dual Diode, 300 V, 225 mA

BAV99 Dual Diode, 70 V

Novacap, Venkel, Johanson, Murata

Not installed

C20

4

C22

1

C24,C25

Novacap, Venkel, Johanson, Murata, Panasonic

Novacap, Venkel, Johanson, Murata

Not Installed

C26,C27

4

C30

2,5

C38,C39

Venkel

6

D1,D2

Central Semiconductor

1

D3,D4

Diodes Inc., OnSemiconductor, Fairchild

Murata

FB1,FB2

Ferrite Bead, 600 Ω, ±25%,

200 mA

2,5

L1,L2

68 µH, 120 mA, 4 Ω max, ±10%

A42, NPN, 300 V

TDK, Murata, Panasonic

OnSemiconductor, Fairchild, Zetex

OnSemiconductor, Fairchild

Q1,Q3

Q2

A92, PNP, 300 V

7

Q4

BCP56, NPN, 60 V, 1/2 W

Notes:

1. The Si2400 design survives up to 3500 V longitudinal surges without R27, R28, D3, D4, Z4, and Z5. Adding the R27, R28, D3, D4, Z4,

Z5 enhanced lightning option increases longitudinal surge survival to greater than 6600 V. The isolation capacitors C1, C4, C24, and

C25 must also be rated to greater than the surge voltage. Y-class capacitors are recommended for highest surge survival and are

required for Norway, Sweden, Denmark, and Finland.

2. For FCC-only designs: C14, C38, C39, R12, R13, R31, and R32 are not required; L1 and L2 may be replaced with a short; R2 may be

±5%; with Z1 rated at 18 V, C5 may be rated at 16 V; also see note 9.

3. If the auto answer, ring detect, and caller ID features are not used, R9, R10, C7, C8, C18, and C19 may be removed. In this case, the

RNG1 and RNG2 pins of the Si3015 should be connected to the IGND pin.

4. C22 and C30 may provide an additional improvement in emissions/immunity and/or voice performance, depending on design and

layout. Population option recommended. See "Emissions/Immunity" on page 78.

5. Compliance with EN55022 and/or CISPR-22 conducted disturbance tests requires L1, L2, C38, C39, R31, R32, and RV2. See also

“EN55022 and CISPR-22 Compliance” in Appendix A.

6. Several diode bridge configurations are acceptable (suppliers include General Semi., Diodes Inc.).

7. Q4 may require copper on board to meet 1/2 W power requirement. (Contact manufacturer for details.)

8. When L1 and L2 are used, RV2 must be installed, and D1 and D2 must be 400 V.

9. The R7, R8, R15, and R16, R17, R19 resistors may each be replaced with a single resistor of 1.78 kΩ, 3/4 W, ±1%. For FCC-only

designs, 1.78 kΩ, 1/16 W, ±5% resistors may be used.

10. If the parallel phone detection feature is not used, R25 and R26 may be removed.

11. To ensure compliance with ITU specifications, frequency tolerance must be less than 100 ppm including initial accuracy, 5-year aging,

0 to 70°C, and capacitive loading.

Rev. 1.3

11

Si2400

Component

RV1

Value

Suppliers

Teccor, ST Microelectronics, Microsemi, TI

Not Installed

Sidactor, 275 V, 100 A

270 V, MOV

8

RV2

2

R2

402 Ω, 1/16 W, ±1%

100 kΩ, 1/16 W, ±1%

120 kΩ, 1/16 W, ±5%

5.36 kΩ, 1/4 W, ±1%

56 kΩ, 1/10 W, ±5%

9.31 kΩ, 1/16 W, ±1%

78.7 Ω, 1/16 W, ±1%

215 Ω, 1/16 W, ±1%

2.2 kΩ, 1/10 W, ±5%

150 Ω, 1/16 W, ±5%

10 MΩ, 1/16 W, ±5%

10 Ω, 1/10 W, ±5%

470 Ω, 1/16 W, ±5%

Si2400

Venkel, Panasonic

Silicon Labs

R5

R6

9

R7,R8,R15,R16,R17,R19

3

R9,R10

R11

2

R12

2

R13

R18

R24

10

R25,R26

1

R27,R28

2,5

R31,R32

U1

U2

Si3015

Silicon Labs

11

Y1

4.9152 MHz, 20 pF, 50 ppm, 150

ESR

Not Installed

2

Z1

Zener Diode, 43 V, 1/2 W

Zener Diode, 5.6 V, 1/2 W

Vishay, Motorola, Rohm

1

Z4,Z5

Notes:

1. The Si2400 design survives up to 3500 V longitudinal surges without R27, R28, D3, D4, Z4, and Z5. Adding the R27, R28, D3, D4, Z4,

Z5 enhanced lightning option increases longitudinal surge survival to greater than 6600 V. The isolation capacitors C1, C4, C24, and

C25 must also be rated to greater than the surge voltage. Y-class capacitors are recommended for highest surge survival and are

required for Norway, Sweden, Denmark, and Finland.

2. For FCC-only designs: C14, C38, C39, R12, R13, R31, and R32 are not required; L1 and L2 may be replaced with a short; R2 may be

±5%; with Z1 rated at 18 V, C5 may be rated at 16 V; also see note 9.

3. If the auto answer, ring detect, and caller ID features are not used, R9, R10, C7, C8, C18, and C19 may be removed. In this case, the

RNG1 and RNG2 pins of the Si3015 should be connected to the IGND pin.

4. C22 and C30 may provide an additional improvement in emissions/immunity and/or voice performance, depending on design and

layout. Population option recommended. See "Emissions/Immunity" on page 78.

5. Compliance with EN55022 and/or CISPR-22 conducted disturbance tests requires L1, L2, C38, C39, R31, R32, and RV2. See also

“EN55022 and CISPR-22 Compliance” in Appendix A.

6. Several diode bridge configurations are acceptable (suppliers include General Semi., Diodes Inc.).

7. Q4 may require copper on board to meet 1/2 W power requirement. (Contact manufacturer for details.)

8. When L1 and L2 are used, RV2 must be installed, and D1 and D2 must be 400 V.

9. The R7, R8, R15, and R16, R17, R19 resistors may each be replaced with a single resistor of 1.78 kΩ, 3/4 W, ±1%. For FCC-only

designs, 1.78 kΩ, 1/16 W, ±5% resistors may be used.

10. If the parallel phone detection feature is not used, R25 and R26 may be removed.

11. To ensure compliance with ITU specifications, frequency tolerance must be less than 100 ppm including initial accuracy, 5-year aging,

0 to 70°C, and capacitive loading.

12

Rev. 1.3

Si2400

4. Analog Input/Output

Figure 4 illustrates an optional application circuit to support the analog output capability of the Si2400 for voice

monitoring purposes.

+ 5 V

6

C2

R3

3

2

C4

AOUT

+

–

5

U1

C5

4

R1

C6

C3

Figure 4. Optional Connection to AOUT for a Monitoring Speaker

Table 9. Component Values—Optional Connection to AOUT

‘

Symbol

Value

C2, C3, C5

0.1 µF, 16 V, ±20%

100 µF, 16 V, Elec. ±20%

820 pF, 16 V, ±20%

10 kΩ, 1/10 W, ±5%

10 Ω, 1/10 W, ±5%

47 kΩ, 1/10 W, ±5%

LM386

C4

C6

R1

R2

R3

U1

Si2400

1 V_RMS

Analog Input

AIN/GPIO

0.1 μF

Figure 5. Analog Input Circuit

Rev. 1.3

13

Si2400

5. Functional Description

The Si2400 ISOmodem is a complete modem chipset and global compliance. The Si2400 solution integrates a

with integrated direct access arrangement (DAA) that silicon DAA using Silicon Laboratories’ proprietary

provides a programmable line interface to meet global capacitive isolation technology. This highly integrated

telephone line requirements. Available in two 16-pin DAA can be programmed to meet worldwide PTT

small outline packages, this solution includes a DSP data specifications for ac termination, dc termination, ringer

pump, a modem controller, an analog front end (AFE), a impedance, and ringer threshold. The DAA also can

DAA, and an audio codec.

monitor line status for parallel handset detection and for

overcurrent conditions.

The modem, which accepts simple modem AT

commands, provides connect rates of up to 2400 bps, The Si2400 is designed for rapid assimilation into existing

full-duplex over the Public Switched Telephone Network modem applications. The device interfaces directly

(PSTN) with V.42 hardware support through HDLC through a UART to a microcontroller. The Si2400URT-

framing. To minimize handshake times, the Si2400 can EVB connects directly to a standard RS-232 interface.

implement a V.25-based fast connect. The modem also This allows for PC evaluation of the modem immediately

supports the V.23 reversing protocol and standard alarm upon powerup via HyperTerminal or any standard

formats including SIA.

terminal software.

The Si2400 ISOmodem provides numerous features for The chipset can be fully programmed to meet

embedded modem applications including caller ID international telephone line interface requirements with

detection and decoding for the US, UK, and Japanese full compliance to FCC, CTR21, JATE, and other country-

caller ID formats. Both DTMF decoding and generation specific PTT specifications. In addition, the Si2400 has

are provided on chip as well. Call progress is supported been designed to meet the most stringent worldwide

both at a high level through echoing result codes and at a requirements for out-of-band energy, billing-tone

low level through user-programmable biquad filters and immunity, lightning surges, and safety requirements.

parameters such as ring period, ring on/off time, and

dialing interdigit time.

The Si2400 solution needs only a few low-cost discrete

components to achieve global compliance. See Figure 3

This device is ideal for embedded modem applications on page 10 for a typical application circuit.

due to its small board space, low power consumption,

Table 10. Selectable Configurations

Carrier

Frequency (Hz)

Data Rate

(bps)

Standard

Compliance

Configuration

Modulation

V.21

V.22

FSK

DPSK

QAM

1080/1750

1200/2400

1300/2100

1300/1700

1170/2125

1200/2400

—

300

1200

Full

1

1,2

V.22bis

V.23

2400

No retrain

1200/75

600/75

300

Full; plus reversing

(Europe)

FSK

V.23

Bell 103

FSK

DPSK

DTMF

Pulse

FSK

Full

Bell 212A

Security

1200

40

Full

SIA—Pulse

SIA Format

Notes:

—

Low

Full

1170/2125

300 half-duplex

300 bps only

1. The V.22 and V.22bis standards refer to V.14 DTE (UART) configurations. The Si2400 does not support V.14 breaks.

In order to support overspeeding by the remote modem, the Si2400 DTE speed must be greater than the modem

(line) data rate.

2. The Si2400 only adjusts its DCE rate from 2400 bps to 1200 bps if it is connecting to a V.22-only (1200 bps only)

modem. Because the V.22bis specification does not outline a fallback procedure, the host should implement a

fallback mechanism consisting of hanging up and connecting at a lower baud rate. Retraining to accommodate

changes in line conditions which occur during a call must be implemented by terminating the call and redialing.

14

Rev. 1.3

Si2400

5.1. Digital Interface

5.2. Configurations and Data Rates

The Si2400 has a universal asynchronous serial The Si2400 can be configured to any of the Bell and

interface (UART) compatible with standard CCITT operation modes in Table 12. The modem, when

microcontroller serial interfaces. After power-up or configured for V.22bis, will connect at 1200 bps if the far

reset, the speed of the serial (Data Terminal end modem is configured for V.22. This device also

Equipment—DTE) interface is set by default to supports SIA and other protocols for the security

2400 bps with the 8-bit, no parity, and one stop bit (8N1) industry. Table 10 provides the modulation method,

format described below. The PCM codec serial interface carrier frequencies, data rate, baud rate and notes on

is disabled by default and CLKOUT is set to standard compliance for each modem configuration of

9.8304 MHz after power-up or reset.

the Si2400. Table 12 shows example register settings

(S07) for some of the modem configurations.

The serial interface DTE rate can be modified by writing

SE0[2:0] (SD) with the value corresponding to the As shown in Figure 6, 8-bit and 9-bit data modes refer to

desired DTE rate. (See Table 11.) This is accomplished the DTE format over the UART. Line data formats are

with the command ATSE0=xx where xx is the configured through registers S07 (MF1) and S15 (MLC).

hexadecimal value of the SE0 register.

If the number of bits specified by the DTE format differs

from the number of bits specified by the DCE (Data

Communications Equipment or Line) format, the MSBs

will either be dropped or bit-stuffed, as appropriate. For

example, if the DTE format is 9 data bits (9N1), and the

line data format is 8 data bits (8N1), then the MSB from

the DTE will be dropped as the 9-bit word is passed

from the DTE side to the DCE (line) side. In this case,

the dropped ninth bit can then be used as an escape

mechanism. However, if the DTE format is 8N1and the

line data format is 9N1, an MSB equal to 0 will be added

to the 8-bit word as it is passed from the DTE side to the

DCE side.

Table 11. DTE Rates

DTE Rate (bps)

300

SE0[2:0] (SD)

000

001

010

011

100

101

110

111

1200

2400

9600

19200

228613

245760

307200

The Si2400 UART does not continuously check for stop

bits on the incoming digital data. Therefore, if the TXD

pin is not high, the RXD pin may echo meaningless

characters to the host UART. This requires the host

UART to flush its receiver FIFO upon initialization.

Immediately after the ATSE0=xx string is sent, the host

UART must be reprogrammed to the new DTE rate in

order to communicate with the Si2400.

The three highest DTE rates (228613, 245760, 307200)

are required for transferring PCM data from the host to

the Si2400 PCM interface for the transmission of voice

over the phone line or through the voice codec.

Si2400

Si3015

TXD

RXD

RJ11

Table 12. Modem Configuration Examples

(S07[7] (HDEN) = 0, S07[6] (BD) = 0)

DTE Interface

Data Rate: SE0[2:0] (SD)

Data Format: SE0[3] (ND)

DCE (Line) Interface

Data Rate: S07 (MF1)

Data Format: S15 (MLC)

Modem Protocol

V.22bis

Register S07 Values

Figure 6. Link and Line Data Formats

5.2.1. Command/Data Mode

0x06

0x02

0x03

0x00

0x01

0x16

0x24

0x12

0x20

V.22

Upon reset, the modem will be in command mode and

will accept AT-style commands. An outgoing modem

call can be made using the “ATDT#” (tone dial) or

“ATDP#” (pulse dial) command after the device is

configured. If the handshake is successful, the modem

will respond with the “c”, “d”, or “v” string and enter data

mode. (The byte following the “c”, “d”, or “v” will be the

first data byte.) At this point, AT-style commands are not

accepted. There are three methods which may be used

to return the Si2400 to command mode:

V.21

Bell 212A

Bell 103

V.23 (1200 tx, 75 rx)

V.23 (75 tx, 1200 rx)

V.23 (600 tx, 75 rx)

V.23 (75 tx, 600 rx)

Rev. 1.3

15

Si2400

Use the ESC pin—To program the GPIO3 pin to

function as an ESCAPE input, set GPIO3

SE0[2:0] (SD) setting and terminates with a stop bit.

Data from the host for transmission to the remote

modem is shifted to the Si2400 on TXD, beginning with

a start bit, LSB first at the DTE rate determined by the

SE2[5:4] = 11b. In this setting, a positive edge

detected on this pin will return the modem to

command mode. The “ATO” string can be used to re- SE0[2:0] setting and terminates with a stop bit. After the

enter data mode.

middle of the stop bit time the Si2400 will begin looking

for a logic 1 to logic 0 transition signaling the start of the

next character on TXD to be sent to the line (remote

modem).

Use 9-bit data mode—If 9-bit data format with

escape is programmed, a 1 detected on bit 9 will

return the modem to command mode. (See Figure 2

on page 9.) This is enabled by setting

5.2.3. 9-Bit Data Mode (9N1)

SE0[3] (ND) = 1 and S15[0] (NBE) = 1 . The ATO

b

The 9-bit data mode is set by SE0[3] (ND) = 1 . It is

b

string can be used to reenter data mode. Ninth bit

escape does not work in the security modes.

asynchronous, full duplex, and uses a total of 11 bits

including a start bit (logic 0), 9 data bits, and a stop bit

(logic 1). Data received from the line (remote modem) is

transferred from the Si2400 to the host on the RXD pin.

Data transfer to the host begins when the Si2400

asserts a logic 0 start bit on RXD. Data is shifted out of

the Si2400 LSB first at the DTE rate determined by the

SE0[2:0] (SD) setting and terminates with a stop bit.

Data from the host for transmission to the line (remote

modem) is shifted to the Si2400 on TXD, beginning with

a start bit, LSB first at the DTE rate determined by the

S-Register SE0[2:0] (SD) setting and terminates with a

stop bit. After the middle of the stop bit time the Si2400

will begin looking for a logic 1 to logic 0 transition

signaling the start of the next character on TXD to be

sent to the line (remote modem).

Use TIES—The time independent escape sequence

is a sequence of three escape characters (“+”

characters by default). Once these characters have

been recognized, the modem enters the Command

state without sending a confirming result code to the

terminal. The modem then starts an internal prompt

delay timer. From that point on if an AT<CR>

(attention) command is received before the timer

expires, the timer is stopped and the “O” response

code is sent to the terminal. This indicates that the

Si2400 is in command mode.

If any other data is received while the timer is

running, the timer is stopped, the device returns to

the online state, and the data appearing on TXD is

sent to the remote modem.

If the timer expires, a confirming “O” response code

is sent to the terminal indicating that the modem is in

command mode.

The ninth data bit may be used to indicate an escape by

setting S15[0] (NBE) = 1 . In this mode, the ninth data

b

bit will normally be set to 0 when the modem is online.

When the ninth data bit is set to 1, the modem will go

offline into Command mode and the next frame will be

interpreted as an AT command. Data mode can be

reentered using the ATO command.

TIES is enabled by writing register

S14[5] (TEO) = 1 . Both the escape character “+”

b

and the escape time-out period are programmable

via registers S0F (TEC) and S10 (TDT), respectively.

5.2.4. Flow Control

Note: TIES is not the recommended escape solution for the

most robust designs. Any data string containing the

sequence “+++AT<CR>” will interrupt a data sequence

erroneously.

No flow control is needed if the DTE rate and DCE rate

are the same. If the serial link (DTE) data rate is set

higher than the line (DCE) rate of the modem, flow

control is required to prevent loss of data to the

transmitter.

Whether using an escape method or not, when the

carrier is lost, the modem will automatically return to

command mode and report “N”.

To control data flow, the clear-to-send (CTS) pin is used.

As shown in Figure 2 on page 9, the CTS pin will

normally be high, and will be low whenever the modem

is able to accept new data. The CTS pin will go high

again as soon as a start bit is detected on the TXD pin

and will remain high until the modem is ready to accept

another character.

5.2.2. 8-Bit Data Mode (8N1)

The 8-bit data mode is the default mode after power-up

or a reset and is set by SE0[3] (ND) = 0 . It is

b

asynchronous, full duplex, and uses a total of 10 bits

including a start bit (logic 0), 8 data bits, and a stop bit

(logic 1). Data received from the remote modem is

transferred from the Si2400 to the host on the RXD pin.

Data transfer to the host begins when the Si2400

asserts a logic 0 start bit on RXD. Data is shifted out of

the Si2400 LSB first at the DTE rate determined by the

16

Rev. 1.3

Si2400

default).

5.3. Low Power Modes

Total Powerdown. Setting SF1[5] = 1 and

b

The Si2400 has three low power modes. These are

described below:

SF1[6] = 1 will place the Si2400 into a total

b

powerdown mode. All logic is powered down,

including the crystal oscillator and clock-out pin.

Only a hardware reset can restart the Si2400.

DSP Powerdown. The DSP processor can be

powered down by setting register

SEB[3] (PDDE) = 1 .

b

In this mode, the serial interface still functions and

the modem will detect ringing and intrusion.

However, no modem modes or tone detection

features will function.

5.4. Global DAA Operation

The Si2400 chipset contains an integrated silicon direct

access arrangement (silicon DAA) that provides a

programmable line interface to meet international

telephone line requirements. Table 13 gives the DAA

register settings required to meet various country PTT

standards. A detailed description of the registers in

Table 13 can be found in "Appendix A—DAA Operation"

on page 78.

Wake-Up-On-Ring. By issuing the ATz command,

the Si2400 goes into a low power mode where both

the microcontroller and DSP are powered down.

Only an incoming ring or a total reset will power up

the chip again. Return from wake-on-ring will trigger

the ALERT pin if S62[4] (WOR) = 1 (WOR = 0 by

b

Table 13. Country-Specific Register Settings

Register

Country

SF5

SF7

SF6

FLVM

S62

LLC

OHS

ACT

DCT

RZ

RT

LIM

VOL

1

Australia

1

0

1

0

1

0

1

0

1

0

1

0

01

10

11

01

10

11

01

10

01

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

2

Brazil

1, 3, 4

CTR21

Czech Republic

1, 5

FCC

Latvia

1,6

Malaysia

New Zealand

Nigeria

1

Philippines

7

Poland , Slovenia

7

South Africa

7

South Korea

Note:

1. See "DC Termination" on page 79 for more information.

2. The following countries require the same settings as Brazil: Armenia, China, Egypt, Georgia, Japan, Jordan,

Kazakhstan, Kyrgyzstan, Malaysia, Muldova, Oman, Pakistan, Qatar, Russia, Syria, Taiwan, Thailand, Ukraine.

3. The following countries require the same settings as CTR21: Austria, Bahrain, Belgium, Bulgaria, Croatia, Cyprus,

Denmark, Estonia, European Union, Finland, France, Germany, Greece, Guadeloupe, Iceland, Ireland, Israel, Italy,

Lebanon, Liechtenstein, Luxembourg, Malta, Martinique, Morocco, Netherlands, Norway, Polynesia (French),

Portugal, Reunion, Spain, Sweden, Switzerland, Turkey, and the United Kingdom.

4. When changing into or out of CTR21 Mode, LLC should be written first. SDF must be enabled (i.e., DGSR ≠ 0) and

SFS should be reprogrammed before each call.

5. The following countries require the same settings as FCC: Argentina, Brunei, Canada, Chile, Columbia, Dubai,

Equador, El Salvador, Guam, Hong Kong, Hungary, India, Indonesia, Kuwait, Macao, Mexico, Peru, Puerto Rico,

Romania, Saudi Arabia, Singapore, Slovakia, Tunisia, UAE, USA, Venezuela, Yemen.

6. Supported for loop current ≥ 20 mA.

7. SF5[1] (RZ) should only be set for Poland, South Africa and South Korea if the ringer impedance network (C15, R14,

Z2, Z3) is not populated.

Rev. 1.3

17

Si2400

absolute detector is chosen, the Si2400 algorithm will

detect an intrusion if LVCS is less than the value stored

in on-hook intrusion threshold, S11[4:0] (AVL). In other

words, an intrusion has occurred if LVCS < AVL.

5.5. Parallel Phone Detection

The Si2400 has the ability to detect a phone or other

device that is off hook on a shared line. This enables the

ISOmodem to avoid interrupting a call in progress on a

shared line and to intelligently handle an interruption by

another device when the Si2400 is using the line. An

automatic algorithm to detect parallel phone intrusion

(defined as an off-hook parallel handset) is provided by

default.

AVL defaults to 1000 , or 25 V on powerup. The

b

absolute detector is the correct method to use for most

countries and should also be used to detect the

presence (or absence) of a line connection.

Under the condition of a very short line and a current-

limiting telephone off hook, the off-hook line voltage can

be as high as 40 V. The minimum on-hook voltage may

not be much greater. This condition can occur on phone

lines with current-limiting specifications such as France.

For these lines, a differential detector is more

appropriate.

5.5.1. On-Hook Intrusion Detection

To implement intrusion detection, the Si2400 uses loop

voltage sense register SDB (LVCS). When on hook,

LVCS monitors the line voltage. (When off-hook, it

measures line current.) LVCS has a full scale of 87 V

with an LSB of 2.75 V. The first code (0 → 1) is skewed

such that a 0 indicates that the line voltage is < 3.0 V.

The voltage accuracy of LVCS is ±20%. The user can

read these bits directly when on hook through register

SDB (LVCS).

The differential detector method checks line status

every 26.66 ms. The detector compares (LVCS (t –

0.02666) – LVCS (t)) to the differential threshold level

set in register S11[7:5] (DVL). The default for DVL is

0x02 (5.5 V). If the threshold is exceeded (LVCS (t –

0.02666) – LVCS (t) > DVL), an intrusion is detected. If

(LVCS (t) – LVCS (t – 0.02666) > DVL), then the

intrusion is said to have terminated.

The automatic on-hook detector algorithm can be

tripped by either an absolute level or by a voltage

differential by selecting S13[3] (ONHD) = 0

for

b

absolute or S13[3] (ONHD) = 1 for differential. If the

b

30

25

20

LVCS

BITS

15

10

5

0

3

6

9

12 15 18 21 24 28 30 33 36 39 42 45 47 51 54 57 60 63 66 69 72 75 78 81 84 87

Loop Voltage (V)

100

Figure 7. Loop Voltage—LVCS Transfer Function

18

Rev. 1.3

Si2400

5.5.2. Reporting of an On-Hook Intrusion

(current limiting) operation and the lower curve

representing all other modes. The overload points

indicate excessive current draw. The user can read

these bits directly through SDB (LVCS). Note that as in

the line voltage sense, there is hysteresis between

codes (0.375 mA for CTR21 mode and 0.75 mA for the

alternate mode).

The reporting of an on-hook intrusion is the same

whether or not the differential or absolute algorithm is

chosen.

An “i” result code is sent when an intrusion is detected.

Conversely an “I” result code is sent when an intrusion

has terminated. S14[1] (IND) indicates the current

intrusion status and is set for as long as an intrusion is

detected.

The off-hook intrusion algorithm does not begin to

operate immediately after going off-hook. This is to

avoid triggering an off-hook intrusion interrupt due to off-

hook transients. The time between going off-hook and

enabling the intrusion algorithm defaults to 1 second

and may be set via S82[7:4] (IST).

In addition, if the LVCS returns a value of zero, an “l”

result code is sent to the host. If the LVCS becomes

non-zero after having gone to zero, an “L” result code is

sent to the host. S14[2] (NLD) indicates the current line

voltage status and is set for as long as the LVCS is zero.

Once the intrusion settling time (IST) has elapsed, the

Si2400 executes one of the three off-hook intrusion

It is possible to suppress the result codes by setting

algorithms,

depending

on

the

settings

of

S14[7] MRCD = 1 and selectively re-enabling desired

b

SDF[6:0] (DSGR) and S13[4] (OFHD). See Table 14.

result codes using the S62 register. Suppressing result

codes in this fashion does not affect the setting of the

NLD and IND bits of the S14 register. Suppressing the

result codes is the best approach if polling the S14

register to monitor the intrusion status is preferred.

Table 14. Off-Hook Intrusion Algorithms

Algorithm

Differential #1

Differential #2

Absolute

OFHD

SDF

0

1

0

It is also possible to suppress the result codes by

setting S33[6] (DON). However, this approach will stop

the updating of the S14 register, rendering the on-hook

intrusion algorithm completely disabled. This approach

may be used if the host checks LVCS directly prior to

going off-hook.

≠0

x

5.5.4. Differential Algorithm #1 (default)

If (LVCS (t – 800 ms) – LVCS (t)) > S12[7:5] (DCL), then

an intrusion is deemed to have taken place. If (LVCS (t)

– LVCS (t – 800 ms)) > DCL, then the intrusion is

deemed to have completed. Default DCL is 2. This

comparison occurs every 200 ms.

5.5.3. Off-Hook Intrusion Detection

When the Si2400 is off-hook, it can detect another

phone going off-hook by monitoring the dc loop current.

The loop current sense transfer function is shown in

Figure 8 with the upper curve representing CTR21

Overload

30

25

CTR21

20

15

10

5

LVCS

BITS

0

3

6

9

12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 78 81 84 87 90 93

140

Loop Current

(mA)

Figure 8. Loop Current—LVCS Transfer Function

Rev. 1.3

19

Si2400

5.5.5. Differential Algorithm #2

an intrusion, if any, into ACL. Therefore, ACL may be

used for the next off-hook event even if the current off-

hook sample contains an intrusion. Except for the first

initialization, no host intervention is necessary.

This differential algorithm has features added to

Differential Algorithm #1. The additional features are as

follows:

The Si2400 clears ACL automatically under a hardware

reset. Additionally, ACL is cleared if the modem is on-

hook, and the phone line is disconnected and then

reconnected once again.

Programmable deglitch filter to minimize false

intrusions

Ability to preset initial LVCS reference prior to going

off-hook

If the host hardware resets the Si2400 between off-hook

events, the host may choose to store the ACL value

prior to reset, and then restore this value to ACL prior to

the next off-hook event.

Optional time window where intrusions are blocked

and ignored

5.5.6. Deglitch Filter

To avoid triggering an off-hook intrusion interrupt due to

a transient or glitch on the telephone line, a deglitch

filter is inserted before the off-hook intrusion algorithm.

The sample rate of the deglitcher is set by

SDF[6:0] (DGSR). (If DGSR = 0, the Differential

Algorithm #1 is implemented.) Before a sample is

passed to the off-hook intrusion algorithm, it must be

confirmed by a subsequent sample of the same value.

Otherwise, it is not submitted to the off-hook algorithm.

5.5.8. Intrusion Blocking

Differential Algorithm #2 may be disabled for a period of

time after dialing begins. This can avoid triggering an

off-hook intrusion interrupt due to pulse dialing or line

transients from central office switching. The method to

block the intrusion algorithm is set via S82[1:0] (IB). If

IB = 10b is chosen, S29 (IS) can be used to set this

blocking to an absolute time.

In order to detect if an intrusion does occur during

blocking and is sustained until after the blocking, the

Si2400 will measure the difference in LVCS between the

sample before blocking and the sample after blocking.

In order to filter out glitches of up to 1 second in

duration, for example, DGSR should be set to 1 second

(SDF[6:0] = 011001b). In this example, an intrusion

event that lasts for more than two seconds is

guaranteed to be treated as a real intrusion. Intrusion

events between one second and two seconds in

duration may or may not be treated as an intrusion. The

recommended setting for DGSR is one second, which

should work for most applications.

5.5.9. Absolute Algorithm

If the absolute detector is chosen (S13[4] [OFHD] = 0 ),

b

the Si2400 will detect an intrusion under the condition

that LVCS is less than the off-hook intrusion threshold,

S12[4:0] (ACL). In other words, it is determined that an

intrusion has occurred if LVCS < ACL. ACL defaults to 0

(12 mA) on powerup. Because the loop current can vary

from 20 mA to 100 mA, depending on the line, a factory

preset threshold is not useful.

Once a sample has been deemed valid by the deglitch

filter, the off-hook algorithm operates as follows:

z

If (LVCS (t – 80 ms DGSR) – LVCS (t)) > DCL, then an

intrusion is deemed to have taken place. Default DCL

z

To use this absolute mode, the host must measure the

line current and set the threshold accordingly. A

measurement of the loop current is accomplished by

going off-hook (issuing the “ATDT;” command), reading

LVCS after 800 ms, and going back on hook using the

“ATH” command. This measured value of LVCS should

be used to determine the threshold register ACL. If this

method is used, the loop current should be measured

on a periodic basis to account for drift in line resistance.

is 2. This comparison occurs every 40 ms DGSR.

Because the compared value is continually updated, the

off-hook intrusion algorithm automatically adjusts to

account for drift in line resistance.

5.5.7. LVCS Initialization

If an intrusion begins within the time window defined by

S82[7:4] (IST), it is possible for an intrusion to go

unreported because the initial LVCS used as the

reference is sampled after the intrusion has begun.

5.5.10. Reporting Off-Hook Intrusions

S12[4:0] (ACL) is used to avoid this problem. Prior to

going off-hook, the host can set the ACL register to a

known value of LVCS with the Si2400 off-hook and all

parallel phones or other devices on-hook. If this value is

not known, such as on the first off-hook event using this

specific phone line, ACL should be set to 0, indicating

no known LVCS reference.

The primary method of reporting an off-hook intrusion

event to the host is through the use of the ALERT pin.

The ALERT function is assigned to GPIO4 by setting

SE2[7:6] (GPIO4) = 11b.

In general, “i” and “I” result codes are sent when the

modem detects an intrusion. However, it is important to

note that these result codes are not always reported.

When the modem is in the data mode, the “i” and “I”

Once the Si2400 goes back on-hook, it automatically

writes the value of the last known LVCS sample prior to

20

Rev. 1.3

Si2400

result codes are suppressed, and the ALERT pin is the

only method of reporting an intrusion to the host.

5.6. Loop Current Detection

In addition to monitoring parallel phone intrusion, it is

possible to monitor the loss of loop current. This feature

can be enabled by setting SE82[3] (LCLD) = 1. This

feature is disabled by default. If the loop current is too

low for normal DAA operation, the “l” result code is sent,

and S14[2] (NLD) is set. Once the loop current returns

to a normal current state, the “L” result code is sent and

S14[2] (NLD) is cleared. The ALERT pin is also

asserted if enabled. The “L” and “l” result codes are not

always sent. The principles governing the reporting of

the “i” and “I” result codes apply to the “L” and “l” result

codes. The status of the S14 register is unchanged for

800 msec after an off-hook to on-hook event. This delay

preserves the S14 register contents at the time the

ALERT is asserted.

The “i” and “I” result codes may be sent to the host

under the following conditions:

1. If the modem is in the process of establishing a connection

using the “ATDT#<cr>” or “ATA<cr>” commands and prior

to the “c”, “v”, or “d” result codes.

2. If the modem is in command mode and a call is initiated

using “ATDT#;” command.

3. If the modem is used in the security modes (ATDT#!0-!7)

(except !2).

4. If the modem is used in the !2 security mode while the

modem is not actively receiving/sending FSK data.

Once the ALERT pin is asserted as a consequence of

an intrusion, it is the responsibility of the host software

to negate it by clearing SE3[3] (GPD4) directly.

S14[1] (IND) is an indication of the current intrusion

status. It is updated whenever the “i” and “I” result

codes are sent to the host or when the ALERT pin is

asserted. If set, IND indicates that an intrusion event is

in progress. In addition, the status of IND persists for

800 msec after an off hook to on-hook event. After

800 msec has elapsed, IND functions as documented

for the on-hook intrusion algorithm. This delay

preserves the S14 register contents at the time the

ALERT is asserted.

5.7. Carrier Detect/Loss

The Si2400 can provide the functionality of a loss-of-

carrier pin similar to the CD pin functionality in an RS-

232 connection. If programmed as an ALERT, GPIO4

will go high in data mode when either parallel phone

intrusion or a loss-of-carrier is detected. When used in

this manner, the host detects a low-to-high transition on

GPIO4 (ALERT), escapes into command mode, and

reads S14[1] (IND). If high, IND indicates intrusion. If

low, IND indicates loss-of-carrier.

When using the modem as a standard data modem and

the ALERT pin asserts, the host software may need to

force the modem back into command mode. In the

command mode, the host can determine if the ALERT

assertion was caused by an intrusion or a carrier loss by

querying the S14 register.

A carrier detect function may also be implemented by

setting SE2[3:2] (GPIO2) = 01b, SE4[0] (TRSP) =0 ,

b

and SOC[7] (CDE) = 1 .

b

If the Si2400 does not reliably detect loss of carrier, use

the following AT command string:

ATSE8=00SE6=00SE5=25SE8=01SE6=0ASE5=3DSE8=00

If the modem is dialing (after the ATDT string but before

the “c”, “v”, or “d” result codes), sending any character

places the modem back into command mode. In the

case in which the modem has already connected (in

data mode after the “c”, “v” or “d” result code has been

sent), an escape sequence is required to place the

modem in the command mode.

This moves the carrier-off level to within 0.5 dB of the

carrier-on level. (The default is 2.5 dB.) This reduces

the likelihood that the Si2400 will detect its own output

as a remote modem carrier.

5.8. Overcurrent Detection

The Si2400 will always go off hook with the current-

limiting mode enabled. This allows no possibility of

damage for voltages up to about 48 V. However, at

higher voltages the 43 V Zener protection device will

begin to conduct and could be damaged if the power is

applied for too long.

The best method of regaining control, without having to

know the exact status of the modem, is by issuing an

escape sequence (asserting the ESC pin and waiting a

short period of time) and sending a carriage return

character. The escape sequence takes care of the case

in which the modem is in the connected state, and the

carriage return character aborts the dialing if the modem

is in the process of dialing to get a connection. If the

modem is already on-hook and in command mode, the

carriage return character and escape sequence are

benign events.

The Si2400 will detect the value of the loop current at a

programmable time set by S32 (OCDT) after going off-

hook (default = 20 ms). If the loop current is too high, an

“x” will be echoed back to the host to indicate a fault

condition. The host may then check S14[3] (OD) to

confirm an overcurrent condition.

The user can optionally put the Si2400 into a lower drive

Rev. 1.3

21

Si2400

mode, which is similar to the current-limiting mode but decoded caller ID data. The wetting pulse may cause

has reduced hookswitch drive. This feature allows the false intrusions to be detected. To prevent this, setting

Si2400 to remain off-hook on a digital line for a longer S14[7] (MRCD) = 1 is recommended.

b

period of time without damage. If the Si2400 does not

detect overcurrent after the time set by S32 (OCDT), the

correct line termination is applied. Another option is

5.9.3. Japan Caller ID Operation

After a polarity reversal and the first ring burst are

detected, the Si2400 is taken off hook. The Si2400 then

looks for mark bits. If three seconds elapse without

detecting a mark bit, the Si2400 hangs up and echoes

an “H”. Otherwise, after 40 1s (marks) have been

detected, the Si2400 will search for a start bit, echo an

“m” for mark, and begin assembling characters and

transmitting them out through the serial port. When the

carrier is lost, the Si2400 immediately hangs up and

echoes “N”.

setting S13[5] (OFHE) = 1 . When this bit is set, the

b

Si3015 is forced to CTR21 termination during the short

period of time from the off-hook event until the timeout

defined by OCDT. After the OCDT timeout, the desired

dc termination is restored.

If it is determined that a false overcurrent condition has

been detected, the host may choose to set

S62[6] (OCR) = 1 to disable the reporting of the “x”

b

result code.

5.9.4. Force Caller ID Monitor

5.9. Caller ID Decoding Operation

The Si2400 may be used to continuously monitor the

phone line for the caller ID mark signals. This can be

useful in systems that require detection of caller ID data

before the ring signal, voice mail indicator signals, and

Type II caller ID monitor support. To force the Si2400

into caller ID monitor mode, set SOC[6:5] (CIDM) = 11b.

In addition, the Force Caller ID Monitor feature can

require that the caller ID FSK data be preceded by

either a DTMF A or D or a channel seizure pattern by

setting CIDM appropriately.

The Si2400 supports full caller ID detection and decode

for US Bellcore, UK, and Japanese standards. To use

the caller ID decoding feature, the following set-up is

necessary:

1. Set SE0[3] (ND) = 0 (Set modem to 8N1 configuration)

b

2. Set S13[1] (CIDU) = 1 (Set modem to Bellcore type caller

b

ID) or S13[2] (CIDB) = 1 (Set modem to UK type caller

b

ID) or S13[7] (JID) = 1 (Set modem to Japanese type

b

caller ID)

Note: CIDM should be disabled before going off-hook.

5.9.1. Bellcore Caller ID Operation

5.9.5. DTMF Caller ID

The Si2400 will detect the first ring burst signal and

echo an “R” to the host. The device will then start

searching for the caller ID preamble sequence after the

appropriate time-out. When 50 continuous mark bits

have been detected, the “m” response will be echoed to

indicate that the mark has been detected and that caller

ID data will follow.

In order for the Si2400 to detect DTMF-based caller ID,

it must be put into the data mode for DTMF detection.

This mode behaves similarly to the ATA0 and ATDT!0

modes in that once a command is sent, ATO must be

sent to return to the detection state. The following

commands place the Si2400 into an on-hook DTMF

detection mode:

At this point the algorithm will look for the first start bit,

assemble the characters and transmit them out of the

serial port as they are detected.

ATS1D=02SF0=02SE8=02SE6=01S83=66O<CR>

The Si2400 cannot distinguish between DTMF sent

from the central office or DTMF sent from a parallel

phone. For this reason, the host processor will need to

know the proper format of the caller ID information to

interpret whether the incoming digits are caller ID

information or if they are the outgoing digits of a parallel

phone. DTMF-based caller ID typically uses the

extended DTMF digits (A, B, C, D, *, #) to indicate the

start and end of the caller ID data.

Finally, the Si2400 will continue detecting ring bursts

and echoing “R” for each burst and will automatically

answer after the correct number of rings set by S00

(NR).

5.9.2. UK Caller ID Operation

When the Si2400 detects a line reversal, it will echo an

“f” to the host. It will then start searching for the Idle

State Tone Alert Signal. When this signal has been

detected, the Si2400 will transmit an “a” to the host.

After the Idle State Tone Alert Signal is completed, the

Si2400 will apply the wetting pulse for the required

15 ms by quickly going off hook and on hook. From this

point on, the algorithm is identical to that of Bellcore in

that it will search for the channel seizure signal and the

marks before echoing an “m” and will then report the

While in this mode, the Si2400 will not report detection

of ringing and must rely on the caller ID string as an

indication that the phone is ringing. It is necessary to

end the DTMF detection mode by sending the ATH

command before originating (ATDT) or answering (ATA)

a call.

22

Rev. 1.3

Si2400

5.10. Tone Generation and Tone Detection 5.11. PCM Data Mode

The Si2400 provides comprehensive and flexible tone The Si2400 has the ability to bypass the modem

generation and detection. This includes all tones algorithm and send 14-bit PCM data, sampled at

needed to establish a circuit connection and to set up 9600 Hz, across the DAA. To use this mode, it is

and control a communication session. The tone necessary to set the serial link (DTE) rate to at least

generation furnishes the DTMF tones for PSTN auto 228613 bps SE0[2:0] (SD) = 101b, set S13[0] (PCM)

dialing and the supervisory tones for call establishment. = 1 , and set SE1[7:6] (MCKR) = 00 . The data format

b

The tone detection provides support for call progress (Figure 9) requires that the high byte be sent first

monitoring. The detector can also be user-programmed containing bits D13–D7. The LSB (B0) must equal zero.

to recognize up to four tones and two tone detection The low byte must be sent next containing bits D6–D0;

bandpass filters.

the LSB (B0) must equal one. The receive data format is

the same.

DTMF tones may be detected and generated by using

the “ATA0” and “ATDT!0” commands described in the In PCM data mode, the line can be answered or

AT command section. A description of the user- originated using the “ATDT#;” command. (The “;” is

programmable tones can be found in "7.1.DSP used to keep the modem from leaving the command

Registers" on page 40.

mode.) When PCM data mode is enabled (set

S13[0] (PCM) = 1 and SE4[5:4] (DRT) = 001

b

The Si2400 DTMF decoder is designed for single loop

applications such as local detection of a parallel DTMF

device. Applications requiring DTMF detection across

two loops such as programming via a remote keypad

are not supported.

(default)), data will immediately begin streaming into

z

and out of the serial port at a 9600 Hz 2 word rate. In

this mode, the controller will not detect dial tones or

other call progress tones. If desired, the user can

monitor these tones using manual call progress

detection prior to entering the PCM data mode.

To exit the PCM data mode, an escape must be

performed either by pulsing the ESC pin or by using 9-

bit data mode and setting the ninth bit. (TIES cannot be

used in PCM data mode.) The escape command will

disable PCM streaming, and the controller will again

accept AT style commands.

PCM Receive Timing

8-Bit Data

High-Byte

Low-Byte

RXD

D0

B1

D1

B2

D2

B3

D4

B5

D5

B6

D6

B7

D3

B4

D7

B1

D8

B2

D9

B3

D10

B4

D11

B5

D12

B6

D13

B7

B0

Stop

B0

Stop

Start

PCM Transmit Timing

8-Bit Data

High-Byte

Low-Byte

TXD

D0

B1

D1

B2

D2

B3

D4

B5

D5

B6

D6

B7

D3

B4

D7

B1

D8

B2

D9

B3

D10

B4

D11

B5

D12

B6

D13

B7

B0

Stop

B0

Stop

Start

Note: Baud rates (programmed through register SEO) can be set to the following: 228613, 245760 and 307200.

Figure 9. PCM Timing

Rev. 1.3

23

Si2400

Data Mode (DRT = 00b)

Si2400

DSP

Si3015

DSPOUT

TXD

RJ11

A.

DSPIN

RXD

AOUT

AIN

(Call Progress)

Voice Mode (DRT = 01b)

Si2400

DSP

DSPOUT

Si3015

TXD

RXD

RJ11

B.

DSPIN

AOUT

AIN

(Voice Out)

(Voice In)

Loopback Mode (DRT = 10b)

Si2400

DSP

DSPOUT

TXD

RXD

C.

DSPIN

AOUT

AIN

Codec Mode (DRT = 11b)

Si2400

DSP

Si3015

DSPOUT

TXD

RXD

RJ11

D.

DSPIN

AOUT

AIN

(Voice Out)

(Voice In)

Figure 10. Signal Routing

24

Rev. 1.3

Si2400

5.12. Analog Codec

5.13. V.23 Operation/V.23 Reversing

The Si2400 features an on-chip, voice quality codec. The Si2400 supports full V.23 operation including the

The codec consists of a digital to analog converter V.23 reversing procedure. V.23 operation is enabled by

(DAC) and an analog to digital converter (ADC). The setting S07 (MF1) = xx10xx00 or xx01xx10 . If

b

sample rate for the codec is set to 9.6 kHz. When the S07[5] (V23R) = 1 , then the Si2400 will transmit data at

b

codec is powered on (SE4[1] [APO] = 1 ), the output of 75 bps and receive data at either 600 or 1200 bps. If

b

the DAC is always present on the Si2400 AOUT pin. S07[4] (V23T) = 1 , then the Si2400 will receive data at

b

When the codec is powered off (APO = 0 ), a PWM 75 bps and transmit data at either 600 or 1200 bps.

b

output is present on the AOUT pin instead. In order to S07[2] (BAUD) is the 1200 or 600 bps indicator.

use the ADC, one of the four GPIO pins must be BAUD = 1 will enable the 1200/600 V.23 channel to run

b

selected as an analog input (AIN) by programming SE2 at 1200 bps while BAUD = 0 will enable 600 bps

b

(GPIO).

operation.

Figure 10 shows the various signal routing modes for When a V.23 connection is successfully established, the

the Si2400 voice codec, which are programmed through modem will respond with a “c” character if the

register SE4[5:4] (DRT). Figure 10A shows the data connection is made with the modem transmitting at

routing for data mode. This is the default mode used for 1200/600 bps and receiving at 75 bps. The modem will

modem data formats. In this configuration, AOUT respond with a “v” character if a V.23 connection is

produces a mixed sum of the DSPOUT and DSPIN established with the modem transmitting at 75 bps and

signals and is typically used for call progress monitoring receiving at 1200/600 bps.

through an external speaker. The relative levels of the

DSPOUT and DSPIN signals that are output on the

This allows a modem that is transmitting at 75 bps to

AOUT pin can be set through SF4[1:0] (ATL) and

The Si2400 supports the V.23 turnaround procedure.

initiate a “turnaround” procedure so that it can begin

transmitting data at 1200/600 bps and receiving data at

SF4[3:2] (ARL).

Figure 10B shows the format for sending analog voice 75 bps. The modem is defined as being in V.23 master

across the DAA to the PSTN. AIN is routed directly mode if it is transmitting at 75 bps and it is defined as

across the DAA to the telephone line. In this being in slave mode if the modem is transmitting at

configuration, AOUT produces a mixed sum of the 1200/600 bps. The following paragraphs give a detailed

DSPOUT and DSPIN signals. The relative levels of the description of the V.23 turnaround procedure.

DSPOUT and DSPIN signals that are output on the

5.13.1. Modem in master mode

AOUT pin can be set through registers ATL and ARL.

To perform a direct turnaround once a modem

The DSP may process these signals if it is not in PCM

connection is established, the master host goes into

data mode. Thus, the DSP may be used in this

online-command-mode by sending an escape

configuration, for example, to decode DTMF tones. This

command (Escape pin activation, TIES, or ninth bit

is the mode used with the “!0” and “A0” commands.

escape) to the master modem. (Note that the host can

Figure 10C shows the loopback format, which can be

initiate a turnaround only if the Si2400 is the master.)

used for in-circuit testing.

The host then sends the ATRO command to the Si2400

Figure 10D shows the codec mode. This format is to initiate a V.23 turnaround and to go back to the online

useful, for example, in voice prompting, speaker (data) mode.

phones, or any systems involving digital signal

processing. In this mode, DSPOUT is routed to both the

390 Hz to 1300 Hz), and wait to detect a 390 Hz carrier

AOUT pin and to the telephone line, and AIN is routed

The Si2400 will then change its carrier frequency (from

for 440 ms. If the modem detects more than 40 ms of a

390 Hz carrier in a time window of 440 ms, it will echo

directly to DSPIN.

In all the DRT formats, the DSP must be in PCM mode the “c” response character. If the modem does not

in order to pass DSPIN and DSPOUT directly to and detect more than 40 ms of a 390 Hz carrier in a time

from TXD and RXD.

window of 440 ms, it will hang up and echo the “N” (no

carrier) character as a response

Rev. 1.3

25

Si2400

5.13.2. Modem in slave mode

command, or the auto-answer mode. (The auto-answer

mode is implemented by setting register S00 (NR) to a

non-zero value.) When the call is connected, a “c”, “d”,

or a “v” is echoed to the host controller. The host may

now send/receive data across the UART using either

the 8-Bit Data or 9-Bit Data formats with flow control.

Configure GPIO4 as ALERT (S2E[7:6] [GPIO4] = 11 ).

b

The Si2400 performs a reverse turnaround when it

detects a carrier drop longer than 20 ms. The Si2400

then reverses (it changes its carrier from 1300 Hz to

390 Hz) and waits to detect a 1300 Hz carrier for

220 ms. If the Si2400 detects more than 40 ms of a At this point, the Si2400 will begin framing data into the

1300 Hz carrier in a time window of 220 ms, then it will HDLC format. On the transmit side, if no data is

set the ALERT pin (GPIO4) and the next character available from the host, the HDLC flag pattern is sent

echoed by the Si2400 will be a “v”.

repeatedly. When data is available, the Si2400

computes the CRC code throughout the frame and the

data is sent with the HDLC zero-bit insertion algorithm.

If the Si2400 does not detect more than 40 ms of the

1300 Hz carrier in a time window of 220 ms, then it

reverses again and waits to detect a 390 Hz carrier for HDLC flow control operates in a similar manner to

220 ms. Then, if the Si2400 detects more than 40 ms of normal asynchronous flow control across the UART and

a 390 Hz carrier in a time window of 220 ms, it will set is shown in Figure 11. In order to operate flow control

the ALERT pin (GPIO4) and the next character echoed (using the CTS pin to indicate when the Si2400 is ready

by the Si2400 will be a “c”.

to accept a character), a DTE rate higher than the line

rate should be selected. The method of transmitting

HDLC frames is as follows:

At this point, if the Si2400 does not detect more than

40 ms of the 390 Hz carrier in a time window of 220 ms,

then it will hang up, set the ALERT pin (GPIO4), and the

next character echoed by the Si2400 will be an “N” (no

carrier).

1. After the call is connected, the host should begin sending

the frame data to the Si2400, using the CTS flow control to

ensure data synchronicity. A 1-deep character FIFO is

implemented in the Si2400 to ensure that data is always

available to transmit.

Successful completion of a turnaround procedure in

either master or slave will automatically update

S07[4] (V23T) and S07[5] (V23R) to indicate the new

status of the V.23 connection.

2. When the frame is complete, the host should simply stop

sending data to the Si2400. As shown in Figure 11B, since

the Si2400 does not yet recognize the end-of-frame, it will

expect an extra byte and assert CTS. If CTS is used to

cause a host interrupt, then this final interrupt should be

ignored by the host.

In order to avoid using the ALERT pin, the host may

also be notified of the ALERT condition by using 9-bit

data

mode.

Setting

S15[0] (NBE) = 1

and

b

S0C[3] (9BF) = 0 will configure the ninth bit on the

Si2400 TXD path to function exactly as the ALERT pin

has been described.

3. When the Si2400 is ready to send the next byte, if it has

not yet received any data from the host, it will recognize

this as an end-of-frame, raise CTS, calculate the final CRC

code, transmit the code, and begin transmitting stop flags.

b

5.14. V.42 HDLC Mode

4. After transmitting the first stop flag, the Si2400 will lower

CTS indicating that it is ready to receive the next frame

from the host. At this point the process repeats as in

step 1.

The Si2400 supports V.42 through hardware HDLC

framing in all modem data modes. Frame packing and

unpacking, including opening and closing flag

generation and detection, CRC computation and

checking, zero insertion and deletion, and modem data

transmission and reception are all performed by the

Si2400. V.42 error correction and V.42bis data

compression must be performed by the host.

The method of receiving HDLC frames is as follows:

1. After the call is connected, the Si2400 searches for flag

data. Then, once the first non-flag word is detected, the

CRC is continuously computed, and the data is sent

across the UART (8-Bit Data or 9-Bit Data mode) to the

host after removing the HDLC zero-bit insertion. The DTE

rate of the host must be at least as high as that of data

transmission. HDLC mode only works with 8-bit data

words; the ninth bit is used only for escape on TXD and

End-of-Frame Received (EOFR) on RXD.

The digital link interface in this mode uses the same

UART interface (8-Bit Data and 9-Bit Data formats) as in

the asynchronous modes and the ninth data bit may be

used as an escape by setting S15[0] (NBE) = 1 . When

b

using HDLC in 9-Bit Data mode, if the ninth bit is not

used as an escape, it is ignored.

2. When the Si2400 detects the stop flag, it will send the last

data word in the frame as well as the two CRC bytes and

determine if the CRC checksum matches. Thus, the last

two bytes are not frame data, but are the CRC bytes,

which can be discarded by the host. If the checksum

matches, then the Si2400 echoes “G” (good). If the

To use the HDLC feature on the Si2400, the host must

first

enable

HDLC

operation

by

setting

S07[7] (HDEN) = 1 . Next, the host may initiate the call

b

or answer the call using either the “ATDT#”, the “ATA”

26

Rev. 1.3

Si2400

checksum does not match, the Si2400 echoes “e” (error).

Additionally, if the Si2400 detects an abort (seven or more

contiguous ones), then it will echo an “A”.

When the “G”, “e”, or “A” (referred to as a frame result

word) is sent, the Si2400 raises the EOFR (end of frame

receive) pin (see Figure 10B). The GPIO1 pin must be

5.15. Fast Connect

In modem applications that require fast connection

times, it is possible to reduce the length of the

handshake.

If the Si2400 is set up as an answering modem, the

answer tone transmitted by the Si2400 may be

shortened by setting S1E (TATL) = 0x00 and setting

S34 (TASL) to the desired answer tone length. For the

most robust operation, it is recommended that the

answer tone sent by the answering modem be at least

10 msec (S34 (TASL) = 0x06).

configured as EOFR by setting SE4[3] (GPE) = 1 . In

b

addition to using the EOFR pin to indicate that the byte is a

frame result word, if in 9-bit data mode (set S15[0] (NBE) =

1 ), the ninth bit will be raised if the byte is a frame result

b

word. To program this mode, set S0C[3] (9BF) = 1 and

b

SE0[3] (ND) = 1 .

b

3. When the next frame of data is detected, EOFR is lowered

and the process repeats at step 1.

If the Si2400 is configured as an originating modem,

setting the No Answer Tone bit (S33[1] [NAT] = 1 )

forces the Si2400 to recognize a short answer tone,

thereby reducing the overall connection sequence.

b

To summarize, the host will begin receiving data

asynchronously from the Si2400. When each byte is

received, the host should check the EOFR pin (or the

ninth bit). If the EOFR pin (or the ninth bit) is low, then

the data is valid frame data. If the EOFR pin (or the

ninth bit) is high, then the data is a frame result word.

Additional modem handshaking control can be adjusted

through the registers shown in Table 15. These

registers are most useful if the user has control of both

the originating and answer modems.

Host begins frame N

Host finished sending frame N

Host begins frame N + 1

TXD

Start

Frame N

Stop

Start

Frame N + 1

Si2400 detects end of frame N.

(CTS used as normal flow control.)

Si2400 ready for byte 1 of frame N

Si2400 ready for byte 1

of frame N + 1.

CTS

Note: Figure not to scale.

A. Frame Transmit

RXD

Start

Receive Data

Stop

Start

CRC Byte 1

Stop

Start

CRC Byte 2

Stop

Start

Frame Result W ord Stop

EOFR

(or bit 9)

B. Frame Receive

Figure 11. HDLC Timing

Rev. 1.3

27

Si2400

Table 15. Handshaking Control Registers

Register

S1E

S1F

S20

S21

S22

S23

S24

S25

S26

S27

S28

S2A

S2F

S30

S31

S34

S35

Name

TATL

ATTD

UNL

Function

Transmit Answer Tone Length

Units

1 sec

Default

0x03

0x2D

0x5D

0x09

0xA2

0xCB

0x08

0x3C

0x0C

0x78

0x08

0xD2

0x3C

0x00

0x3C

0x5A

0xA2

Answer Tone to Transmit Delay

Unscrambled Ones Length—V.22

Transmit Scrambled Ones Delay—V.22

Transmit Scrambled Ones Length—V.22

V.22/22b Data Delay Low

5/3 msec

TSOD

TSOL

VDDL

53.3 msec

5/3 msec

VDDH V.22/22b Data Delay High

(256) 5/3 msec

5/3 msec

SPTL

VTSO

S1 Pattern Time Length V.22b

V.22b 1200 bps Scrambled Ones Length

53.3 msec

5/3 msec

VTSOL V.22b 2400 bps Scrambled Ones Length Low

VTSOH V.22b 2400 bps Scrambled Ones Length High

(256) 5/3 msec

5/3 msec

RSO

FCD

Receive Scrambled Ones V.22b Length

FSK Connection Delay Low

5/3 msec

FCDH

RATL

TASL

RSOL

FSK Connection Delay High

(256) 5/3 msec

5/3 msec

Receive Answer Tone Length

Answer Tone Length (only used in S1E [TATL] = 0x00)

Receive V.22 Scrambled Ones Length

5/3 msec

UART DTE rate is set to 2400 bps, given that the clock

input is 4.9152 MHz. The MCKR register conserves

power via slower clocking of the microcontroller for

specific applications where power conservation is

required. Table 16 shows the configurations for different

values of MCKR.

5.16. Clock Generation Subsystem

The Si2400 contains an on-chip clock generator. Using

a single master clock input, the Si2400 can generate all

modem sample rates necessary to support V.22bis,

V.22/Bell212A, and V.21/Bell103 standards and a

9.6 kHz rate for audio playback. Either a 4.9152 MHz

clock on XTALI or a 4.9152 MHz crystal across XTALI

and XTALO form the master clock for the Si2400. This

clock source is sent to an internal phase-locked loop

(PLL) which generates all necessary internal system

clocks. The PLL has a settling time of ~1 ms. Data on

RXD should not be sent to the device prior to settling of

the PLL.

Table 16. MCKR Configurations

SE1[7:6]

(MCKR)

Controller

Clock (MHz)

Modes

All (default)

0 0

0 1

9.8304 MHz

4.9152 MHz All except V.22bis,

PCM

The CLKOUT pin outputs a 78.6432 MHz/(N + 1) clock

which may be used to clock a microcontroller or other

devices in the system. N may be programmed via

SE1[4:0] (CLKD) to any value from 1 to 31. N defaults to

7 on power-up. CLKOUT is disabled by setting N = 0.

1 0

1 1

2.4576 MHz Command only

Reserved

SE1[7:6] (MCKR) allows the user to control the

microcontroller clock rate. On powerup, the Si2400

28

Rev. 1.3

Si2400

contain several commands, one after the other. If there

are no characters between AT and <CR>, the modem

6. AT Command Set

The controller provides several vital functions including responds with “O” after the carriage return.

AT command parsing, DAA control, connect sequence

6.1. Command Line Execution

control, DCE protocol control, intrusion detection,

parallel phone off-hook detection, escape control, caller The characters in a command line are executed one at

ID control and formatting, PCM mode control, ring a time. Unexpected command characters will be

detect, DTMF control, call progress monitoring, and ignored, but unexpected data characters may be

HDLC framing. The controller also writes to the control interpreted incorrectly.

registers that configure the modem. Virtually all

After the modem has executed a command line, the

interaction between the host and the modem is done via

result code corresponding to the last command

the controller. The controller uses AT (ATtention)

executed is returned to the terminal or host. In addition

commands and S-Registers to configure and control the

to the “ATH” and “ATZ” commands, the commands

which warrant a response (e.g., “ATSR?” or “ATI”) must

modem.

The modem has two basic modes of operation, the be the last in the string and followed by a <CR>. All

Command mode and the Data mode. The Si2400 is other commands may be concatenated on a single line.

asynchronous in both the Command mode and the Data To echo command line characters, set the Si2400 to

mode. The modem is in the Command mode at power- echo mode using the E1 command.

up, after a reset, before a connection is made, after a

All numeric arguments, including S-register address and

connection is dropped, and during a connection after

value, are in hexidecimal format and two digits must

successfully “Escaping” from the data mode back to the

always be entered.

command mode using one of the methods previously

6.2. < CR > End Of Line Character

described. The following section describes the AT

command set available in the Command mode.

This character is typed to end a command line. The

The Si2400 supports a subset of the typical modem AT value of the <CR> character is 13 decimal, the ASCII

command set since it is intended for use with a carriage return character. When the <CR> character is

dedicated microcontroller instead of general terminal entered, the modem executes the commands in the

applications. AT commands begin with the letters AT command line. Commands which do not require a

and are followed directly (no space) by the command. response are executed immediately and do not

(These commands are also case-sensitive.) All AT need a <CR>.

commands must be entered in upper case including AT

except w##, r#, m#, q#, and z (wakeup-on-ring).

Table 17. AT Command Set Summary

AT commands can be divided into two groups, control

commands and configuration commands. Control

commands, such as ATD, cause the modem to perform

Command Function

A

DT#

DP#

E

Answer line immediately with modem.

Tone dial number.

an action (going off-hook and dialing). The value of this

type of command is changed at a particular time to

perform a particular action. For example, the command

“ATDT1234<CR>” will cause the modem to go off-hook

and dial the number 1234 via DTMF. This action will

exist only during a connection attempt. No enduring

change in the modem configuration will exist after the

connection or connection attempt has ended.

Pulse dial number.

Local echo on/off.

H

Hangup/go on line.

I

Chip revision.

M

Speaker control options.

Return online.

O

Configuration

commands

change

modem

RO

S

V.23 reverse.

characteristics until they are modified or reversed by a

subsequent configuration command or the modem is

reset. Modem configuration status can be determined

with the use of “ATSR?<CR>” Where R is the two

character hexadecimal address of an S-register.

Read/write S-Registers.

Write S-Register in binary.

Read S-Register in binary.

Monitor S-Register in binary.

Read S-Register in binary.

Software reset.

w##

r#

m#

q#

Z

A command line is defined as a string of characters

starting with AT and ending with an end-of-line

character, <CR> (13 decimal). Command lines may

z

Wakeup on ring.

Rev. 1.3

29

Si2400

ATDT;

ATH

ATDT#

6.3. AT Command Set Description

A

Answer

The “A” command makes the modem go off hook and

respond to an incoming call. This command is to be

executed after the Si2400 has indicated a ring has

occurred. (The Si2400 will indicate an incoming ring by

echoing an “R”.)

The length of the flash is determined by how quickly the

commands are entered. No comma is necessary for the

second dial because ATS01 sets the number of

seconds before dialing. Set S07[6] (BD) for blind dial.

6.3.1. Automatic Tone/Pulse Dialing

This command is aborted if any other character is

transmitted to the Si2400 before the answer process is

completed.

The Si2400 can be set up to try DTMF dialing and

automatically revert to pulse dialing if it determines that

the line is not DTMF-capable. This feature is best

explained by the following example:

Auto answer mode is entered by setting S00 (NR) to a

non-zero value. NR indicates the number of rings before

answering the line.

If it is desired that the telephone number 12345 be

dialed, it is normally accomplished through either the

ATDT12345 or the ATDP12345 command. In the force

pulse dialing mode of operation, the following string

should be issued instead:

Upon answering, the modem communicates by

whatever protocol has been determined via the modem

control registers in S07 (MF1).

If no transmit carrier signal is received from the calling

modem within the time specified in S39 (CDT), the

modem hangs up and enters the idle state.

ATDT1,p12345

If the result code returned is “t,”, it indicates that the

dialing was accomplished using DTMF dialing. If the

result code returned is “tt,”, it indicates that the dialing

was accomplished using pulse dialing.

D

Dial

DT#

DP#

Tone Dial Number.

Pulse Dial Number.

In the above example, the Si2400 dials the first digit “1”

The D commands make the modem dial a telephone using DTMF dialing. The “,” is used to pause in order to

call according to the digits and dial modifiers in the dial ensure that the central office has had time to accept the

string following the command. A maximum of 64 digits is DTMF digit “1”. When the Si2400 processes the “p”

allowed. A DT command performs tone dialing, and a command, it attempts to detect a dial tone. If a dial tone

DP command performs pulse dialing.

is detected, the DTMF digit “1” was not effective, hence

the line does not support DTMF dialing. Conversely, if

the dial tone is not detected, the DTMF digit “1” was

effective, and the line does support DTMF dialing. The

character after the “p” may or may not be dialed,

depending on whether the DTMF digit “1” was effective

or not. If the “1” was effective (DTMF mode), the

character after the “p” is skipped. The next DTMF digit

to be dialed is “2”. Subsequent digits are all DTMF. If the

“1” was not effective, the first character after the “p” (the

“1”) is pulse dialed, and subsequent digits are all pulse

dialed.

The “ATS07=40DT;” command can be used to go off

hook without detecting dial tone or dialing.

The dial string must contain only the digits “0–9”, “*”, “#”,

“A”, “B”, “C”, “D”, or the modifiers “;”, “/”, or “,”. Other

characters will be interpreted incorrectly. The modifier

“,” causes a two second delay (added to the spacing

value in S04) in dialing. The modifier “/” causes a

125 ms delay (added to the spacing value in S04) in

dialing. The modifier “;” returns the device to command

mode after dialing and must be the last character.

If any character is received by the Si2400 between the

ATDT#<CR> (or ATDP#<CR>) command and when the

connection is made (“c” or “d” is echoed), the extra

character is interpreted as an abort, and the Si2400

returns to command mode, ready to accept AT

commands. A line feed character immediately following

the <CR> will be treated as an “extra character” and will

abort the call.

E

Command Mode Echo

Tells the Si2400 whether or not to echo characters sent

from the terminal.

EO

Does not echo characters sent from the terminal.

E1

Echo characters sent from the terminal.

If the modem does not have to dial (i.e., “ATDT<CR>” or

“ATDP<CR>” with no dial string), the Si2400 assumes

H

Hangup

the call was manually established and attempts to make Hang up and go into command mode (go offline).

a connection.

I

Chip Identification

The following may be used to perform a hook-flash:

30

Rev. 1.3

Si2400

This command causes the modem to echo the chip examples are given below.

revision for the Si2400 device.

6.4.1. ATSR Commands

0 = Revision A

The ATSR commands are generally used to write to or

read from S-registers. The address, R, and the value, N,

must be written into the AT command as a two character

hexadecimal value between 00 and FF. An S-Register is

written with the command “ATSR=N”. The hexadecimal

address and value parameters appearing on the

terminal or PC screen are actually transmitted to the

modem as the hexadecimal equivalents of each

character. Likewise, the value N stored in S-register R is

read back to the terminal with the ATSR? command as

two hexadecimal characters. For example, read the

value of S35 after the Si2400 has been reset.

1 = Revision B

2 = Revision C, etc.

M

Speaker On/Off Options

These options are used to control AOUT for use with a

call progress monitor speaker.

M0

Speaker always off.

M1

Speaker on until carrier established. The modem sets

SF4[3:2] (ARL) = 11 and SF4[1:0] (ATL) = 11 after a

b

connection is established.

Terminal

Entry

Sent to Modem Response Display

M2

Speaker always on.

ATS35?<CR> 41 54 53 33 35

3F 0D

41 32

A2

M3

Speaker on after last digit dialed, off at carrier detect.

Return to Online Mode

6.4.2. # Commands

O

The # commands offer several performance and

convenience advantages for embedded applications

over the more traditional ATSR-style commands. The #

parameter is entered as the ASCII equivalent of a

hexadecimal value representing the S-register address

This command returns the modem to the online mode. It

is frequently used after an escape sequence to resume

communication with the remote modem.

RO

Turn-Around

This command initiates a V.23 “direct turnaround” or content. This parameter is sent to the modem as the

sequence and returns online.

hexadecimal equivalent of the ASCII value. The #

commands offer a more rapid method for reading and

writing S-Registers since fewer characters are sent to or

6.4. S-Register Control

S-registers control Si2400 configuration and provide received from the modem.

status information. Therefore, writing to and reading

from S-registers is central to the operation of the

6.4.3. w## Write S-Register

This command is analogous to the ATSR=N command.

modem. There are two fundamental methods for writing

to and reading from Si2400 S-Registers. The first and

most common method uses the ATSR=N and ATSR?

commands. These commands are used by

communication software packages and are universally

supported by modem chips. The second method uses

the ATw##, ATr#, ATm#, and ATq# commands and is

designed to reduce data flow and streamline

performance in embedded systems. When ATSR

commands are used, each character of the two

character hexadecimal values for both R and N are sent

From a terminal, the first # following w is the ASCII

equivalent of the hexadecimal address of the S-Register

and the second # is the ASCII equivalent of the

hexadecimal value of the S-Register. For example, write

the value 58h to S34.

Terminal

Entry

Sent to Modem Response Display

(hex)

ATw4X

41 54 77 34 58

—

to the AT command parser for decoding and action 6.4.4. r# Command Read S-Register

immediately instead of waiting for a <CR>. Additionally,

This command is analogous to the ATSR? command.

From a terminal, the # following r is the ASCII

equivalent of the hexadecimal address of the S-

Register. The modem will echo the register contents as

the ASCII equivalent of the hexadecimal value of the

contents. This command executes immediately and

does not require a carriage return. Modem result codes

a carriage return, <CR>, is required to terminate the

ATSR? command (not ATSR=N). When the

#

commands are used, # is the single character ASCII

equivalent of the two character hexadecimal S-Register

address or value and no carriage return is required for

any of the # commands. Further explanations and

Rev. 1.3

31

Si2400

must be disabled by setting S14[7] (MRCD) = 1 when

Z

Software Reset (upper-case Z)

b

using this command to ensure the host does not

confuse a result code with data. w## and r# are not

required to be on separate lines (no <CR> between

them). Once a <CR> is encountered, AT is required to

begin the next AT command. For example, write the

value 58h to S34 and read it back using # commands

and ATSR commands.

The “Z” command causes a software reset to occur in

the device whereby the registers will return to their

default power up value with the exception of E0, E2,

E4–E7, F8, and F9. These registers are not reset, so

the Si2400 will maintain its current DTE settings, GPIO

definitions, tone detect and transmit settings, and

overload and billing tone detection status. The hardware

reset pin, RESET (Si2400, pin 8), is used to reset the

Si2400 to factory default settings. If other commands

follow on the same line, another AT is needed after the

“Z” (e.g., ATZATS07=06<CR>).

Terminal

Entry

Sent to

Modem (hex)

Response Display

(hex)

ATw4Xr4

41 54 77 34 58

72 34

58

X

z

Wakeup on Ring (lower-case z)

ATS34=58S34 41 54 53 33 34

35 38

58

The Si2400 enters a low-power mode wherein the DSP

and microcontroller are powered down. The serial

interface also stops functioning. In this mode, only the

line-side chip (Si3015) and the communication link

function. An incoming ring signal or line transient

causes the Si2400 to power up and echo an “R”.

Without a ring signal, the host must perform a hardware

reset (Si2400, pin 8) to power up the Si2400. Return

from wake-on-ring can also be set to trigger the ALERT

?<CR>

3D 35 38 53 33

34 3F 0D

The economy of the # commands is clearly evident from

this example. One caveat when using the # commands

is that the ASCII equivalents of the response can be

displayed as special or graphic characters when using a

terminal emulator program such as HyperTerminal.

However, in an embedded system, it is easy to send

non-ASCII characters.

pin by setting S62[4] (WOR) = 1 .

b

6.5. Alarm Industry AT Commands

6.4.5. m# Command Monitor S-Register

The Si2400 supports a complete set of commands

necessary for making connections in security industry

systems. The Si2400 is configurable in three modes for

these applications. The first mode, DTMF send and

receive, is selected with the “!1” command. The second

mode uses FSK transmit with a tone acknowledgement

and is selected with “!2”. Finally, “!7” is selected for the

tone-on/tone-off mode.

This command is similar to the r# command but is

repeated at the DTE rate until a new byte is transmitted

to the modem. The modem will echo the register

contents to the display as the ASCII equivalent of the

hexadecimal value of the contents. This command

executes immediately and does not require a carriage

return. Modem result codes must be disabled by setting

S14[7] (MRCD) = 1 when using this command to

b

ensure that the host does not confuse a result code with

data.

The following are a few general comments about the

use of “!” commands. Specific details for each command

is given below. The first instance of the “!” must be on

the same line as the ATDT or ATDP command. DRT

6.4.6. q# Command Read S-Register with 0x5500

Offset

must be set to data mode (SE4[5:4] (DRT) = 0 ) before

b

This command is the same as the r# command except

that the response from the Si2400 is formatted as the

hexadecimal value 0x55aa where aa is the hexadecimal

value of the S-register contents. From a terminal, the #

following q is the ASCII equivalent of the hexadecimal

address of the S-register. This command executes

immediately and does not require a carriage return. The

0x5500 offset in the value of the register contents

prevents confusion between data and result codes and

permits the result codes to remain enabled.

attempting to send tones after a “!” command. The three

data-mode escape sequences (“+++”, “escape” pin and

“ninth-bit”) only function in “!2” mode. However, using

the “+++” or “ninth-bit” is not recommended because

characters could be sent to and misinterpreted by the

remote modem. Only the “escape pin” (Si2400, pin 14)

is recommended for use in the “!2” mode. The “!1” and

“!7” modes have special escape provisions described in

their respective sections below. The AT commands for

Alarm Industry applications are described in Table 18.

32

Rev. 1.3

Si2400

Table 18. AT Command Set Extensions

for Alarm Industry

Command

Result

ATDT#!0<CR>

After “,” result code

Dials #

Command

Function

A0

Answer and switch to DTMF monitor

mode

ATSE4=00O<CR>

Detects DTMF tones in

“data mode”

A1

!0

Answer and switch to “SIA Format”

ATDT1234!0

After “,” result code 1234

Sends DTMF tones for

Dial and switch to DTMF monitor

mode

!1

Dial and switch to DTMF security

mode

ATSE4=00O<CR>

Detects DTMF tones in

“data mode”

!2

!7

Dial and switch to “SIA Format”

Dial and switch to pulse security mode

SIA half-duplex mode search

ATH

Terminates call

X1

X2

Example: Dial a number and place the Si2400 in “voice

mode.”

SIA half-duplex return online as

transmitter

Command

ATSEf=02

Result

Powers ADC and DAC

Sets GPIO1 as analog input

Dials #

X3

SIA half-duplex return online as

receiver

6.5.1. A0

ATSE2=02

Answer and transmit the AIN analog input signal on the

telephone line and connect the phone line receive

signal to the AOUT pin (see Figure 10B). This mode

also monitors for local DTMF received signals and user

defined tones. Any received character is echoed. User-

defined tones are echoed as X and Y. Transmission of

any data to the Si2400 UART will cause the modem to

go into the command mode. The modem can then send

DTMF tones via the “ATDT #!0” command (where #

represents a DTMF character 0-9, A-D, # or*) or be

disconnected with the “ATH” command. The “ATDT #!0”

command string does not initiate a new call since the

modem is already connected.

ATDT#!0<CR>

After “,” result code Modem in “voice mode”

Audio placed on Ain

(GPIO1) is transmitted and

received audio is available

on AOUT (see Figure 10).

ATH

Terminates call

ATSE4=02

Returns Si2400 to “data

mode” for next dial com-

mand.

Notes:

DTMF detection is only intended for local detection of a

parallel device, not for detection of a remote source

over two local loops. “Data mode” (see example above)

DTMF detection is reliable on a quiet line without the

presence of interfering audio signals or voice. DTMF

detection, although possible, in the “voice mode” (see

example above) is not recommended and can be

unreliable.

1. DRT must be set to data mode (SE4[5:4](DRT) = 00_b)

before attempting to send tones after a “A0” command.

User defined tones are enabled by setting S14[6]

(UDF) = 1_band require DSP low-level control as

defined on page 40. The online mode can be resumed

by issuing the “ATO” command. (see the “!0” section

for more detail).

2. DTMF detection is only intended for local detection

of a parallel device.

6.5.3. !1

6.5.2. !0

Dial number and follow the DTMF security protocol.

After dialing the number, go to DTMF monitor mode with

no modem connection. After dialing the !0 mode is the

same as the A0 mode described previously.

The format for this command is as follows:

ATDT<phone number>!1<message 1><CR>

K

Example: Dial a number and detect DTMF tones in

“data mode.”

!<message 2><CR>

K

Rev. 1.3

33

Si2400

!<message 3><CR>

signaling is at 300 bps half-duplex FSK. The host can

send the first SIA block after the “c” is received. Once

the block is transmitted, the modem can monitor for the

acknowledge tone by completing the following

sequence:

K

.

1. Place the Si2400 in the command mode by pulsing the

ESCAPE pin (Si2400 pin 14). The “+++” and “ninth-bit”

escape modes will operate in the “!2” mode but are not

recommended because they can send unwanted

characters to the remote modem.

K

!<message n><CR>

The modem dials the phone number and echoes “r”

(ring), “b” (busy), and “c” (connect) as appropriate. “c”

echoes only after the Si2400 detects the Handshake

Tone. After a 250 msec delay, the modem sends the

DTMF tones containing the first message data and

listens for a Kissoff Tone. If the Kissoff Tone is shorter

than or equal to the value stored in S36(KTL)

(default = 480 ms) is detected, the Si2400 echoes a “K”.

A “k” is echoed if the length of the Kissoff Tone is longer

than the S36(KTL) value. The controller can then send

the next message. All messages must be preceded by a

“!” and followed by a <CR> and received by the Si2400

within 250 msec after the “K” is echoed. Setting

2. Issue the “ATX1” command to turn the modem transmitter

off and begin monitoring for the acknowledgment tones.

3. Monitor for a positive (negative) acknowledgment “P” (“N”)

after the tone has been detected for at least 400 msec.

4. The modem, still in command mode, can be placed online

as a transmitter by issuing the “ATX2” command or a

receiver by issuing the “ATX3” command. If tonal

acknowledgement is not used, the host can toggle the

ESCAPE pin to place the Si2400 in the command mode

and issue an “ATX2” or an “ATX3” command to reverse

data direction.

This sequence can be repeated for long messages.

S0C[0] (MCH) = 1 causes a “.” to be echoed when the

b

6.5.6. !7

DTMF tone is turned on and a “/” character to be

echoed when the DTMF tone is turned off. This can help

the host monitor the status of the message being sent.

The previous message can be resent if the host

responds with a “~” after the Si2400 echoes a “K”. Any

character other than a “!” or a “~” sent to the modem

immediately after the “K” will cause the modem to

escape to the command mode and remain off-hook. Any

character except “!” and “~” sent during the transmission

of a message will cause the message to be aborted and

the modem to return to the command mode.

The “!7” mode is a field-configurable tone-on/tone-off

messaging protocol for the alarm industry. There are

many proprietary standards that necessitate a flexible

alarm protocol. The “!7” command fills that need with

programmable usage and timing.

The “!7” mode is entered by issuing the “ATDT<phone

number>!7<message><CR> After the Si2400 connects

to the alarm receiver, it waits for a Handshake Tone

(equivalent to an answer tone). When

a valid

Handshake Tone is received a “c” (connect) is echoed

to the host and the message is sent. The Si2400

echoes a “,” to the host signaling the message is sent,

additional messages can be received from the host and

to mark the start of the intermessage time. The end of

the intermessage time is marked by the “N” result code.

The Si2400 monitors for the Kissoff Tone from the alarm

receiver which acknowledges receipt of the message.

The Si2400 echoes a “K” to indicate the Kissoff Tone

was received or a “^” to indicate it has not been

received prior to the timeout set by S36[3:2] (IDKT).

If the Kissoff Tone is not received within 1.25 seconds,

the modem will echo a “^”. A “~” from the host will cause

the last message to be resent. Any character other than

a “!” or a “~” sent to the modem immediately after the “^”

will cause the modem to escape to the command mode

and remain off-hook. After hanging up, set SCC = 00 to

ensure that a subsequent automatic answer (e.g.

500 = 01) or Bellcore CID will function normally.

6.5.4. A1

Answers a call and follows the “SIA Format” protocol for

Alarm System Communications at 300 bps (see !2).

Register S36 is reconfigured from SKDTL (Second

Kissoff Tone Detector Length) as used in A1 and !1

modes to Alarm 1, a bit-mapped register, in the “!7”

mode. Register S1F is reconfigured from ATTD (Answer

Tone to Transmit Delay) to Alarm3, a bit-mapped

register, in the “!7” mode. S38(Alarm 2) is a bit-mapped

register only used in “!7” mode. The following is a

summary of commands, result codes and S-Registers

encountered in the “!7” mode. After hanging up, set

SCC = 00 to ensure that a subsequent automatic

6.5.5. !2

Dial number and follow the “SIA Format” protocol for

Alarm System Communications.

The modem dials the phone number and echoes “r”

(ring), “b” (busy), and “c” (connect) as appropriate. “c”

echoes only after the Si2400 detects the Handshake

Tone and the speed synchronization signal is sent. The

34

Rev. 1.3

Si2400

answer (e.g. 500 = 01) or Bellcore CID will function

normally.

time window and present for S38[4:2]

(HMT) msec

Basic Command

N

Handshake Tone not detected per above

ATDT<phone number>!7<tone pulse digits 0-9, B- Result codes after “c” received

F><CR>

,

Message sent—start of intermessage time

Result codes after dialing

K

Kissoff Tone detected in S36[3:2] (IDKT)

time window and present for S38[4:2] (HMT)

msec

t

,

Dial tone detected

^

Kissoff Tone not detected per above

Phone number dialed—start of initial

intermessage time

N

Intermessage timeout defined in S36[3:2]

(IDKT) elapsed. A second message received

after the “,” is sent at this time.

r

Ringback tone detected

b

c

Busy tone detected

Handshake Tone detected in S39 (CDT)

Table 19. !7 Parameters

S-Register

S1F

Bits

Name

Function

Alarm 3 Reconfigured from ATTD in !7 mode.

7:5

4:0

7:0

KOT

IMT

Kissoff timeout.

Intermessage timing.

S2B

S2C

S2D

S2E

DTL

Reconfigured from DTL in !7 mode to pulse on time (5/3 ms units).

Reconfigured from DTTO in !7 mode to pulse off time (5/3 ms units).

Reconfigured from SDL in !7 mode to pulse interdigit time (5/3 ms units).

DTTO

SDL

RTCT

Reconfigured from RTLT in !7 mode to handshake end to data TX delay

(10 ms units).

S36

S38

S39

Alarm 1 Reconfigured from SKDTL in !7 mode.

7:6

5:4

3:2

1:0

POF

PON

IDKT

IT

Pulse off time.

Pulse on time.

Intermessage delay and Kissoff timeout.

Interdigit timing.

Alarm 2 Only used in !7 mode.

7

DBD

DCF

HMT

HF

Delay before data.

6:5

4:2

1:0

7:0

Data carrier frequency.

Handshake minimum tone.

Handshake frequency.

CDT

Reconfigured from CDT in !7 mode to handshake tone timeout.

Rev. 1.3

35

Si2400

6.5.7. Intermessage Timing

6.5.8. Returning to Command Mode

Intermessage timing is accomplished in three ways, To return to command mode, the host sends any

relative to the end of the previous message (“,” result character except the “~” and “!” characters. The

code), relative to the Kissoff Tone (“K” result code) or example here uses a <CR> to escape.

relative to the Kissoff timeout (“^” result code).

Once in command mode, all of the AT commands are

If the intermessage timing is relative to the end of the available.

previous message (S36[3:2] [IDKT] = 10 or 11 ), the

b

ATH<CR> Is used to hang up the line. Note that it is

the responsibility of the host to hang up the

line.

intermessage timer begins with the “,” result code. The

Si2400 sends an “N” to mark the time in which the

intermessage timer has timed out. If another message

is received prior to the “N”, the Si2400 keeps the

message and sends it to the receiver at the time the “N”

is sent.

!7xxx<CR> Sends the message xxx without dialing.

The message is sent as soon as the

Si2400 receives the <CR>. After this

message, it is again possible to send

subsequent messages using the “~” and “!”

commands shown above.

If a message is not received within the time frame

defined by “,” and “N”, the Si2400 sends nothing, waits

for the next message and transmits the message as

soon as the host sends the message. This message

may not be accepted by the alarm receiver.

X1

Search for positive and negative acknowledge tones in

SIA half-duplex 300 bps mode. The Si2400 will respond

with “P” when a positive acknowledge is detected and

“N” when a negative acknowledge is detected.

If the intermessage timing is relative to the end of the

Kissoff Tone, the timing begins when the “K” result code

is sent. In the event a kissoff tone was not detected, the

intermessage timing begins when the “^” is sent.

X2

Return to online mode in SIA half-duplex mode as

transmitter.

X3

Return to online mode in SIA half-duplex mode as

receiver.

S39 (CDT)

Before give up on

S38[4:2] (HMT)

min.

handshake

f = S38[1:0] (HF)

Handshake

Tone

Kissoff

Tone

S36[3:2] (IDKT) = 0Xb Intermessage

S38[7] (DBD)

From end of Kissoff Tone

f = S38[6:5] (DCF)

S36[3:2] (IDKT)

Before Indicating lack

of Kissoff

S38[4:2] (HMT)

1st

Digit

Last

Digit

1st

Digit

Last

Digit

min.

2nd Message

S36[3:2] (IDKT) =

1Xb

Intermessage from end of previous

message to start of next message

S36[1:0] (IT) = 0Xb

Interdigit

Intradigit Timing

Pulse On = S36[5:4] (PON)

Pulse Off = S36[7:6] (POF)

Pulse freq = S38[6:5] (DCF)

S36[1:0] (IT) = 1Xb

Interdigit

Figure 12. !7 Security Timing

36

Rev. 1.3

Si2400

6.6.1. Automatic Call Progress Detection

6.6. Modem Result Codes and Call

Progress

The Si2400 has the ability to detect dial, busy and

ringback tones automatically. The following is a

description of the algorithms that have been

implemented for these three tones.

Table 20 shows the modem result codes which can be

used in call progress monitoring. All result codes are a

single character to speed up communication and ease

host processing.

1. Dial Tone. The dial tone detector looks for a dial tone after

going off hook and before dialing is initiated. This can be

bypassed by enabling blind dialing (set S07[6] (BD) =1 ).

b

After going off hook, the Si2400 waits the number of

seconds in S01 (DW) before searching for the dial tone.

In order for a dial tone to be detected, it must be present

for the length of time programmed in S1C (DTT). Once the

dial tone is detected, dialing will commence. If a dial tone

is not detected within the time programmed in S02 (CW),

the Si2400 will hangup and echo an “N” to the user.

Table 20. Modem Result Codes

Command Function

a

British Telecom Caller ID Idle Tone

Alert Detected

b

c

d

Busy Tone Detected

Connect

2. Busy / Ringback Tone. After dialing has completed, the

Si2400 monitors for Busy/Ringback and modem answer

tones. The busy and ringback tone detectors both use the

call progress energy detector. The registers that set the

cadence for busy and ringback are listed in Table 21.

Connect 1200 bps (when pro-

grammed as V.22bis modem)

f

H

I

Hookswitch Flash or Battery Reversal

Detected

Si2400 register settings for global cadences for busy and

ringback tones are listed in Table 22.

Modem Automatically Hanging Up in

Japan Caller ID Mode

Table 21. Busy and Ringback Cadence

Registers

Intrusion Completed (parallel phone

back on hook)

Register

S16

Name

BTON

BTOF

BTOD

RTON

Function

Units

i

Intrusion Detected (parallel phone off-

hook on the line)

Busy tone on time 10 msec

Busy tone off time 10 msec

Busy tone delta time 10 msec

S17

K

k

Kissoff Tone Detected

S18

Contact ID Kissoff Tone too long.

Phone Line Detected

S19

Ringback tone on

time

53.333

msec

L

l

S1A

S1B

RTOF

RTOD

Ringback tone off

time

53.333

msec

No Phone Line Detected

Caller ID Mark Signal Detected

No Carrier Detected

m

N

n

Ringback tone delta 53.333

time msec

No Dial tone (time-out set by CW

[S02])

6.6.2. Manual Call Progress Detection

Because other call progress tones beyond those

described above may exist, the Si2400 supports manual

call progress. This requires the host to read and write

the low-level DSP registers and may require realtime

control by the host. Manual call progress may be

required for detection of application-specific ringback,

dial tone, and busy signals. The section on DSP low

level control should be read before attempting manual

call progress detection.

O

R

r

Modem OK Response

Incoming Ring Signal Detected

Ringback Tone Detected

Dial Tone

t

v

Connect 75 bps TX (V.23 originate

only)

x

Overcurrent State Detected After an

Off-Hook Event

To use this mode, the automatic modem responses

^

,

Kissoff tone detection required

Dialing Complete

should be disabled by setting S14[7] (MRCD) = 1 . The

b

call progress biquad filters can be programmed to have

a custom frequency response and detection level (as

described in “Low Level DSP Control”).

Four dedicated user-defined frequency detectors can

Rev. 1.3

37

Si2400

be programmed to search for individual tones. The four By issuing the “ATDT;” command, the modem will go off

detectors have center frequencies which can be set by hook and return to command mode. The user can then

registers UDFD1–4 (see Table 24). (SE5[6] [TDET] put the DSP into call progress monitoring by first setting

[SE8 = 0x02] Read Only Definition) can be monitored, SE8 = 0x02. Next, set SE5 (DSP2) = 0x00 so no tones

along with TONE, to detect energy at these user- are transmitted, and set SE6 (DSP3) to the appropriate

defined frequencies. The default trip-threshold for code, depending on which types of tones are to be

UDFD1–4 is –34 dBm but can be modified with the DSP detected.

register UDFSL.

Table 22. Si2400 Global Ringer and Busy Tone Cadence Settings

Country

RTON

S19

RTOF

S1A

RTOD

S1B

BTON

S16

BTOF

S17

BTOD

S18

Australia

Austria

0x07

0x12

0x1C

0x12

0x0E

0x1C

0x12

0x07

0x12

0x07

0x17

0x16

0x07

0x12

0x03

0x5D

0x38

0x4B

0x38

0x4B

0x8C

0x5D

0x41

0x4B

0x03

0x4B

0x03

0x46

0x58

0x03

0x4B

0x01

0x0A

0x06

0x08

0x06

0x08

0x0F

0x0A

0x07

0x08

0x01

0x08

0x01

0x0F

0x09

0x01

0x08

0x25

0x1E

0x32

0x19

0x14

0x23

0x32

0x18

0x19

0x1E

0x32

0x25

0x1E

0x32

0x1E

0x19

0x4B

0x32

0x25

0x1E

0x32

0x19

0x32

0x23

0x32

0x24

0x19

0x1E

0x32

0x25

0x1E

0x32

0x1E

0x19

0x4B

0x32

0x04

0x03

0x05

0x03

0x05

0x04

0x05

0x0A

0x03

0x05

0x04

0x03

0x05

0x03

0x08

0x05

Belgium

Brazil

Bulgaria

China

Cyprus

Czech Republic

Denmark

Finland

France

Germany

Great Britain

Greece

Hong Kong, New Zealand

Hungary

Iceland

India

Ireland

Italy, Netherlands, Norway, Thailand,

Switzerland, Israel

Japan, Korea

Luxembourg

Malaysia

0x12

0x07

0x00

0x12

0x07

0x1C

0x12

0x25

0x4B

0x03

0x00

0x4B

0x5D

0x03

0x38

0x5D

0x25

0x4B

0x04

0x08

0x01

0x00

0x08

0x10

0x0A

0x01

0x06

0x0A

0x04

0x08

0x32

0x30

0x23

0x00

0x19

0x32

0x4B

0x14

0x19

0x32

0x30

0x41

0x00

0x19

0x32

0x4B

0x14

0x19

0x32

0x05

0x07

0x00

0x03

0x05

0x08

0x02

0x03

0x05

Malta

Mexico

Poland

Portugal

Singapore

Spain

Sweden

Taiwan

U.S., Canada (default)

38

Rev. 1.3

Si2400

At this point, users may program their own algorithm to

monitor the detected tones. If the host wishes to dial, it

should do so by blind dialing, setting the dial timeout

Table 23. DTMF

Contact

S01 (DW)

to

0

seconds,

and

issuing

an

Tones

“ATDT<Phone Number><CR>;” command. This will

immediately dial and return to command mode.

DTMF

Code

Keyboard

ID

Equivalent

Low

High

Digit

Once the host has detected an answer tone using

manual call progress, the host should immediately

execute the “ATDT” command in order to make a

connection. This will cause the Si2400 to search for the

modem answer tone and begin the correct connect

sequence.

0

1

0

1

2

3

4

5

6

7

8

9

D

*

0

1

2

3

4

5

6

7

8

9

–

B

C

D

E

F

941

697

770

852

941

697

770

852

1336

1209

1336

1477

1209

1336

1477

1209

1336

1477

1633

1209

1477

1633

2

In manual call progress, the DSP can be programmed

to detect specific tones. The result of the detection is

reported into SE5 (SE8 = 0x2) as explained above. The

output is priority encoded such that if multiple tones are

detected, the one with the highest priority whose

detection is also enabled is reported (see SE5 [SE8=02]

Read Only.)

3

4

5

In manual call progress, the DSP can be programmed

to generate specific tones (see SE5[2:0] (TONC)

(SE8 = 02) Write Only). For example, setting

6

7

SE5[2:0] (TONC) = 110 will generate the user-defined

b

tone as indicated by UFRQ in Table 24 with an

amplitude of TGNL.

8

9

Table 23 shows the mappings of Si2400 DTMF values,

keyboard equivalents, and the related dual tones.

10

11

12

13

14

15

#

A

B

C

Rev. 1.3

39

Si2400

with the low bits [7:0] of the DSP register address and

SE6 (DADH) is written with the high bits [15:8] of the

7. Low Level DSP Control

Although not necessary for most applications, the DSP DSP address. When SE8 = 0x01, SE5 (DDL) is written

low-level control functions are available for users with with the low bits [7:0] of the DSP data word

very specific applications requiring direct DSP control.

corresponding to the previously written address and

SE6 (DDH) is written with the high bits [15:8] of the data

word corresponding to the previously written address.

7.1. DSP Registers

Several DSP registers are accessible through the Example 1 below illustrates the proper procedure for

Si2400 microcontroller via S-registers SE5, SE6, SE7 writing to DSP registers.

and SE8. SE5 and SE6 are used as conduits to write

Example1: The user would like to program call

data to specific DSP registers and read status. SE8

progress filter coefficient A2_k0 (0x15) to be 309

defines the function of SE5 and SE6 depending on

(0x135).

whether they are being written to or read from. Care

Host

Command:

must be exercised when writing to DSP registers. DSP

registers can only be written while the Si2400 is on-

hook and in the Command mode. Writing to any register

address not listed in Tables 24 and 25 or writing out-of-

range values is likely to cause the DSP to exhibit

unpredictable behavior.

ATSE8=00SE6=00SE5=15SE8=01SE6=01SE5=35SE8=00

In the command above, ATSE8=00 sets up registers

SE5 and SE6 as DSP address registers. SE6=00 sets

the high bits of the address, and SE5=15 sets the low

bits. SE8=01 sets up registers SE5 and SE6 as DSP

data registers for the previously written DSP address

(0x15). SE6=01 sets the high 6 bits of the 14-bit data

word, and SE5=35 sets the low 8 bits of the 14-bit data

word.

The DSP register address is 16-bits wide and the DSP

data field is 14-bits wide. DSP register addresses and

data are written in hexadecimal. To write a value to a

DSP register, the register address is written then the

data is written. When SE8 = 0x00, SE5(DADL) is written

Table 24. Low-Level DSP Parameters

Name

Description

Function

Default

(dec)

DSP Reg. Addr.

0x0002

XMTL DAA modem full scale transmit level,

default = –10 dBm

Level = 20log (XTML/4096)

–10 dBm

4096

4868

3277

10

0x0003

0x0004

DTML DTMF high tone transmit level,

default = –5.5 dBm

Level = 20log (DTML/4868)

10

–5.5 dBm

DTMT DTMF twist ratio (low/high), default = –2 dBm

Level = 20log (DTMT/3277) –

10

2 dB

0x0005

0x0006

0x0007

0x0008

0x0009

0x000A

0x000B

UFRQ User-defined transmit tone frequency. See

register SE5 (SE8=0x02 (Write Only))

f = (9600/512) UFRQ (Hz)

91

CPDL Call progress detect level (see Figure 13),

default = –43 dBm

Level = 20log (4096/CPDL)

4096

10

–43 dBm

UDFD1 User-defined frequency detector 1. Center

frequency for detector 1.

UDFD1 = 8192 cos (2π f/9600) 4987

UDFD2 = 8192 cos (2π f/9600) 536

UDFD3 = 8192 cos (2π f/9600) 4987

UDFD2 User-defined frequency detector 2. Center

frequency for detector 2.

UDFD3 User-defined frequency detector 3. Center

frequency for detector 3.

UDFD4 User-defined frequency detector 4. Center

frequency for detector 4.

UDFD4 = 8192 cos (2π f/9600)

536

TGNL Tone generation level associated with TONC Level = 20log (TGNL/2896)

2896

10

(SE5 (SE8 = 0x02) Write Only Definition),

default = –10 dBm

– 10 dBm

40

Rev. 1.3

Si2400

Table 24. Low-Level DSP Parameters (Continued)

Name

Description

Function

Default

(dec)

DSP Reg. Addr.

0x000E

UDFSL Sensitivity setting for UDFD1–4 detectors,

default = –43 dBm

Sensitivity = 10log (UDFSL/

4096) – 43 dBm

4096

10

0x0024

0x0025

0x0026

0x0027

CONL Carrier ON level. Carrier is valid once it

reaches this level.

Level = 20log (2620/CONL) – 2620

43 dBm

10

COFL Carrier OFF level. Carrier is invalid once it

falls below this level.

Level = 20log (3300/COFL) – 3300

10

45.5 dBm

AONL Answer ON level. Answer tone is valid once it Level = 10log (AONL/107) –

67

37

10

reaches this level.

43 dBm

AOFL Answer OFF level. Answer tone is invalid

once it fall below this level.

Level = 10log (AOFL/58) –

10

45.5 dBm

Table 25 defines the relationship between SE5, SE6, and SE8.

Table 25. SE5, SE6, and SE8 Relationship

SE8

SE6

Description

DADH DSP register address bits [15:8]

SE5

Description

R/W

W

Name

DADL

DDL

0x00

0x01

0x02

DSP register address bits [7:0]

DSP register data bits [7:0]

W

DDH

DSP register data bits [15:8]

R

DSP1

7 = DSP data available.

6 = Tone detected.

5 = Reserved.

4:0 = Tone type.

0x02

W

DSP3

7 = Enable squaring function.

6 = Call progress cascade disable.

5 = Reserved.

DSP2

7 = Reserved.

6:3 = DTMF tone to transmit.

2:0 = Tone type.

4 = User tone 3 and 4 reporting.

3 = User tone 1 and 2 reporting.

2 = V.23 tone reporting.

1 = Answer tone reporting.

0 = DTMF tone reporting.

Rev. 1.3

41

Si2400

7.2. Call Progress Filters

Table 26. Call Progress Filters

The programmable call progress filter coefficients are

located in DSP address locations 0x0010 through

0x0023. There are two independent 4th order filters A

and B, each consisting of two biquads, for a total of 20

coefficients. Coefficients are 14 bits (–8192 to 8191)

and are interpreted as, for example, b0 = value/4096,

thus giving a floating point value of approximately –2.0

to 2.0. Output of each biquad is calculated as

DSP Register

Coefficient

Default (dec)

Address

0x0010

0x0011

0x0012

0x0013

0x0014

0x0015

0x0016

0x0017

0x0018

0x0019

0x001A

0x001B

0x001C

0x001D

0x001E

0x001F

0x0020

0x0021

0x0022

0x0023

A1_k0

A1_b1

A1_b2

A1_a1

A1_a2

A2_k0

A2_b1

A2_b2

A2_a1

A2_a2

B1_k0

B1_b1

B1_b2

B1_a1

B1_a2

B2_k0

B2_b1

B2_b2

B2_a1

B2_a2

256

–8184

4096

7737

–3801

1236

133

z

w[n] = k0 x[n] + a1 w[n – 1] + a2 w[n – 2]

z

y[n] = w[n] + b1 w[n – 1] + b2 w[n – 2].

4096

7109

–3565

256

The output of the filters is input to an energy detector

and then compared to a fixed threshold with hysteresis

(DSP register CPDL). Defaults shown are a bandpass

filter from 290–630 Hz (–3 dB). These registers are

located in the DSP and thus must be written in the same

manner described in “DSP Registers”.

–8184

4096

7737

–3801

1236

133

The filters may be configured in either parallel or

cascade through SE6[6] (CPCD) with SE8 = 0x02, and

the output of filter B may be squared by selecting

SE6[7] (CPSQ) = 1 . Figure 13 shows a block diagram

b

of the call progress filter structure.

4096

7109

–3565

0

CPCD

1

0

Filter Input

Energy

Detect

Filter B

y = x²

1

0

B

A

B

Max

(A,B)

Hysteresis

TDET

A > B?

1

0

CPCD

CPSQ

Energy

Detect

Filter A

20log 10 (4096/CPDL) –34 dBm

Figure 13. Programmable Call Progress Filter Architecture

42

Rev. 1.3

Si2400

8. S Registers

Any register not documented here is reserved and should not be written. Bold selection in bit-mapped registers

indicate default values.

Table 27. S-Register Summary

“S”

Register

Name Function

Reset

Register Address

(hex)

S00

S01

0x00

0x01

NR

Number of rings before answer; 0 suppresses auto answer.

0x00

0x03

DW

Number of seconds modem waits before dialing after going

off-hook (maximum of 109 seconds).

S02

S03

0x02

0x03

CW

CLW

TD

Number of seconds modem waits for a dial tone before hang-up

added to time specified by DW (maximum of 109 seconds).

0x14

0x0E

Duration that the modem waits (53.33 ms units) after loss of car-

rier before hanging up.

S04

S05

S06

S07

S08

S09

S0A

S0B

S0C

S0D

S0E

0x04

0x05

0x06

0x07

0x08

0x09

0x0A

0x0B

0x0C

0x0D

0x0E

Both duration and spacing (5/3 ms units) of DTMF dialed tones.

0x30

0x18

0x24

0x01

0x0A

0x28

0x4B

0x08

0x00

0x16

0x46

OFFPD Duration of off-hook time (5/3 ms units) for pulse dialing.

ONPD Duration of on-hook time (5/3 ms units) for pulse dialing.

1

MF1

This is a bit mapped register.

2

MNRP Minimum ring period (5/3 ms units).

2

MXRP Maximum ring period (5/3 ms units).

2

ROT

Ringer off time (53.333 ms units).

2

MNRO Minimum ringer off time (10 ms units).

1

MF2

RPE

DIT

This is a bit mapped register.

2

Ringer off time allowed error (53.333 ms units).

Pulse dialing Interdigit time (10 ms units added to a minimum

time of 64 ms).

S0F

S10

S11

S12

S13

S14

S15

S16

0x0F

0x10

0x11

0x12

0x13

0x14

0x15

0x16

TEC

TDT

TIES escape character. Default = +.

0x2B

0x07

0x48

0x40

0x10

0x00

0x84

0x32

z

TIES delay time (256 5/3 ms units).

1

ONHI This is a bit mapped register.

1

OFHI

MF3

MF4

MLC

This is a bit mapped register.

BTON Busy tone on. Time that the busy tone must be on (10 ms units)

for busy tone detector.

Notes:

1. These registers are explained in detail in the following section.

2. The ring detector will only detect ringing if the ring burst on/off times meet the settings in MNRP, MXRP, MNRU, ROT,

and REP.

Rev. 1.3

43

Si2400

Table 27. S-Register Summary (Continued)

Name Function

“S”

Register

Reset

Register Address

(hex)

S17

0x17

BTOF Busy tone off. Time that the busy tone must be off (10 ms units)

for busy tone detector.

0x32

0x0F

S18

0x18

BTOD Busy tone delta. Detector Time Delta (10 ms). A busy tone is

detected to be valid if (BTON – BTOD < on time < BTON +

BTOD) and (BTOF – BTOD < off time < BTOF + BTOD).

S19

S1A

S1B

0x19

0x1A

0x1B

RTON Ringback tone on. Time that the ringback tone must be on

(53.333 ms units) for ringback tone detector.

0x26

0x4B

0x07

RTOF Ringback tone off. Time that the ringback tone must be off

(53.333 ms units) for ringback tone detector.

RTOD Detector time delta (53.333 ms units). A ringback tone is deter-

mined to be valid if (RTON – RTOD < on time < RTON + RTOD)

and (RTOF – RTOD < off time < RTOF + RTOD).

S1C

0x1C

DTT

Dial tone detect time. The time that the dial tone must be valid

before being detected

0x0A

(10 ms units).

S1D

S1E

S1F

0x1D

0x1E

0x1F

DTMFD DTMF detect time. The time that a DTMF tone must be valid

before being detected (10 ms units).

0x03

0x2D

TATL

Transmit answer tone length. Answer tone length in seconds

when answering a call (1 second units).

ATTD Answer tone to transmit delay. Delay between answer tone end

and transmit data start (5/3 ms units). In the !7 mode, this is a bit-

mapped register.

S20

S21

0x20

0x21

UNL

Unscrambled ones length. Minimum length of time required for

detection of unscrambled binary ones during V.22 handshaking

by a calling modem (5/3 ms units).

0x5D

0x09

TSOD Transmit scrambled ones delay. Time between unscrambled

binary one detection and scrambled binary one transmission by

a call mode V.22 modem (53.3 ms units).

S22

S23

0x22

0x23

TSOL Transmit scrambled ones length. Length of time scrambled ones

are sent by a call mode V.22 modem (5/3 ms units).

0xA2

0xCB

VDDL V.22 data delay low. Delay between handshake complete and

data connection for a V.22 call mode modem (5/3 ms units added

to the time specified by VDDH).

S24

S25

0x24

0x25

VDDH V.22 data delay high. Delay between handshake complete and

0x08

0x3C

z

data connection for a V.22 call mode modem (256 5/3 ms units

added to the time specified by VDDL).

SPTL S1 pattern time length. Amount of time the unscrambled S1 pat-

tern is sent by a call mode V.22bis modem (5/3 ms units).

Notes:

1. These registers are explained in detail in the following section.

2. The ring detector will only detect ringing if the ring burst on/off times meet the settings in MNRP, MXRP, MNRU, ROT,

and REP.

44

Rev. 1.3

Si2400

Table 27. S-Register Summary (Continued)

Name Function

“S”

Register

Reset

Register Address

(hex)

S26

0x26

VTSO

0x0C

V.22bis 1200 bps scrambled ones length. Minimum length of

time for transmission of 1200 bps scrambled binary ones by a

call mode V.22bis modem after the end of pattern S1 detection

(53.3 ms).

S27

S28

0x27

0x28

VTSOL V.22bis 2400 bps scrambled ones length low. Minimum length of

time for transmission of 2400 bps scrambled binary ones by a

call mode V.22bis modem (5/3 ms units).

0x78

0x08

VTSOH V.22bis 2400 bps scrambled ones length high. Minimum length

of time for transmission of 2400 bps scrambled binary ones by a

z

call mode V.22bis modem (256 5/3 ms units added to the time

specified by VTSOL).

S29

S2A

0x29

0x2A

IS

Intrusion suspend. When S82[2:1] (IB) = 10 , this register sets

the length of time from when dialing begins that the off-hook

intrusion algorithm is blocked (suspended) (500 ms units).

0x00

0xD2

b

RSO

Receive scrambled ones V.22bis (2400 bps) length.

Minimum length of time required for detection of scrambled

binary ones during V.22bis handshaking by the answering

modem after S1 pattern conclusion (5/3 ms units).

S2B

S2C

S2D

0x2B

0x2C

0x2D

DTL

V.23 direct turnaround carrier length. Minimum length of time that

a master mode V.23 modem must detect carrier when searching

for a direct turnaround sequence (5/3 ms units). In the !7 alarm

mode, this register functions as pulse on time.

0x18

0x08

0x0C

DTTO V.23 direct turnaround timeout. Length of time that the modem

searches for a direct turnaround carrier (5/3 ms units added to a

minimum time of 426.66 ms). In the !7 alarm mode, this register

functions as pulse off time.

SDL

V.23 slave carrier detect loss. Minimum length of time that a

slave mode V.23 modem must lose carrier before searching

for a reverse turnaround sequence (5/3 ms units). In the !7

alarm mode, this register functions as pulse interdigit time

(10 ms units).

S2E

S2F

0x2E

0x2F

RTCT V.23 reverse turnaround carrier timeout. Amount of time a slave

mode V.23 modem will search for carriers during potential

reverse turnaround sequences (5/3 ms units). In the !7 alarm

mode, this register functions as Handshake End to TX Data

delay (10 ms units).

0x84

0x3C

FCD

FSK connection delay low. Amount of time delay added

between end of answer tone handshake and actual modem

connection for FSK modem connections (5/3 ms units).

Notes:

1. These registers are explained in detail in the following section.

2. The ring detector will only detect ringing if the ring burst on/off times meet the settings in MNRP, MXRP, MNRU, ROT,

and REP.

Rev. 1.3

45

Si2400

Table 27. S-Register Summary (Continued)

Name Function

“S”

Register

Reset

Register Address

(hex)

S30

0x30

FCDH FSK connection delay high. Amount of time delay added

between end of answer tone handshake and actual modem con-

0x00

z

nection for FSK modem connections (256 5/3 ms units).

S31

S32

0x31

0x32

RATL Receive answer tone length. Minimum length of time required

for detection of a CCITT answer tone (5/3 ms units).

0x3C

0x0C

OCDT The time after going off hook when the loop current sense bits

are checked for overcurrent status (5/3 ms units).

1

S33

S34

0x33

0x34

MDMO This is a bit mapped register.

0x80

0x5A

TASL

Answer tone length when answering a call (5/3 ms units). This

register is only used if TATL (1E) has a value of zero.

S35

S36

0x35

0x36

RSOL Receive scrambled ones V.22 length (5/3 ms units). Minimum

length of time that an originating V.22 (1200 bps) modem must

detect 1200 bps scrambled ones during a V.22 handshake.

0xA2

0x30

SKDTL Second kissoff tone detector length. The security modes A1 and

!1 will echo a “k” if a kissoff tone longer than the value stored in

SKDTL is detected (10 ms units.) In the !7 security mode, this

register represents a bit-mapped register.

S37

0x37

CDR

Carrier detect return. Minimum length of time that a carrier must

0x20

return and be detected in order to be recognized after a carrier

loss is detected

(5/3 ms units).

1

S38

S39

0x38

0x39

ARM2 This is a bit-mapped register.

0x38

0x3C

CDT

Carrier detect timeout. Amount of time modem will wait for carrier

detect before aborting call (1 second units). In the !7 alarm

mode, this register functions as Handshake Tone Timeout, which

defines how long the Si2400 waits for a handshake prior to send-

ing the “N” result code.

S3A

0x3A

ATD

RP

Delay between going off-hook and answer tone generation when

in answer mode (53.33 ms units).

0x29

S3B

S3C

S62

S82

S83

SD1

SDB

0x3B

0x3C

0x62

0x82

0x83

0xD1

0xDB

Minimum number of consecutive ring pulses per ring burst.

0x03

0x04

0x00

—

1

CIDG This is a bit mapped register.

1

RC

IST

This is a bit mapped register.

DTMF caller ID initialization.

Intrusion state.

DCID

INTS

0x00

LVCS Loop voltage (on-hook)/loop current (off-hook) register

Notes:

1. These registers are explained in detail in the following section.

2. The ring detector will only detect ringing if the ring burst on/off times meet the settings in MNRP, MXRP, MNRU, ROT,

and REP.

46

Rev. 1.3

Si2400

Table 27. S-Register Summary (Continued)

Name Function

“S”

Register

Reset

Register Address

(hex)

1

SDF

SE0

SE1

SE2

SE3

SE4

SE5

0xDF

0xE0

0xE1

0xE2

0xE3

0xE4

0xE5

DGSR This is a bit mapped register.

0x00

0x22

0x07

0x00

1

CF1

This is a bit mapped register.

1

CLK1 This is a bit mapped register.

GPIO This is a bit mapped register.

GPD

CF5

This is a bit mapped register.

DADL (SE8 = 0x00) Write only definition. DSP register address lower

1

bits [7:0].

SE5

0xE5

DDL

(SE8 = 0x01) Write only definition. DSP data word lower bits

[7:0].

0x00

1

SE5

SE6

0xE5

0xE6

DSP1 (SE8 = 0x02) Read only definition. This is a bit mapped register.

DSP2 (SE8 = 0x02) Write only definition. This is a bit mapped register.

0x00

1

DADH (SE8 = 0x00) Write only definition. DSP register address upper

bits [15:8]

SE6

0xE6

DDH

(SE8 = 0x01) Write only definition. DSP data word upper bits

[13:8]

0x00

1

SE6

SE8

SEB

SF0

SF1

SF2

SF4

SF5

SF6

SF7

SF8

SF9

0xE6

0xE8

0xEB

0xF0

0xF1

0xF2

0xF4

0xF5

0xF6

0xF7

0xF8

0xF9

DSP3 (SE8 = 0x02) Write only definition. This is a bit mapped register.

0x00

0x1C

0x00

0x0F

0x08

0x00

0x10

—

DSPR4 Set the mode to define E5 and E6 for low level DSP control.

1

TPD

This is a bit mapped register.

1

DAA0 This is a bit mapped register.

DAA1 This is a bit mapped register.

DAA2 This is a bit mapped register.

DAA4 This is a bit mapped register.

DAA5 This is a bit mapped register.

DAA6 This is a bit mapped register.

DAA7 This is a bit mapped register.

DAA8 This is a bit mapped register.

DAA9 This is a bit mapped register.

0x20

Notes:

1. These registers are explained in detail in the following section.

2. The ring detector will only detect ringing if the ring burst on/off times meet the settings in MNRP, MXRP, MNRU, ROT,

and REP.

Rev. 1.3

47

Si2400

Table 28. Bit Mapped Register Summary

“S”

Register Register Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Default

Binary

Register Address Name

(hex)

HDEN

CDE

BD

V23R

V23T

BAUD CCITT

FSK

S07

S0C

S11

S12

S13

S14

S15

S1F

S33

S36

S38

S3C

S62

S82

SDF

SE0

SE1

SE2

SE3

SE4

SE5

SE6

0x07

0x0C

0x11

0x12

0x13

0x14

0x15

0x1F

0x33

0x36

0x38

0x3C

0x62

0x82

0xDF

0xE0

0xE1

0xE2

0xE3

0xE4

0xE5

0xE6

MF1

MF2

0000_0001

0000_0000

0100_1000

0100_0000

0001_0000

0000_0000

1000_0100

0010_1101

1000_0000

0011_0000

0011_1000

0000_0100

0000_0000

0010_0010

0000_0111

0000_0000

CIDM[1:0]

9BF

BDL

MLB

MCH

DVL[2:0]

DCL[2:0]

BTID

AVL[4:0]

ACL[4:0]

ONHI

OFHI

MF3

JID

OFHE OFHD ONHD CIDB

CIDU

IND

PCM

RD

MRCD

UDF

TEO

AOC

OD

NLD

MF4

ATPRE VCTE FHGE ENGE

KOT[2:0]

STB

BDA[2:1]

IMT[4:0]

NBE

MLC

ARM3

MDMO

ARM1

ARM2

CIDG

RC

DON

POF[1:0]

DOF

PON[1:0]

NAT

TSAC

IDKT[1:0]

IT[1:0]

HF[1:0]

CIDG[2:0]

NLR

IB[1:0]

DBD

DCF[1:0]

HMT[2:0]

CLD

OCR

LLC

WOR

FLS

LCLD

IR

RR

IST[3:0]

IST

DGSR[6:0]

ND

DGSR

CF1

ICTS

SD[2:0]

MCKR[1:0]

CLKD[4:0]

GPIO2[1:0]

GPD4 GPD3 GPD2 GPD1

GPE APO TRSP

CLK1

GPIO

GPD

CF5

GPIO4[1:0]

AING[1:0]

GPIO3[1:0]

GPIO1[1:0]

NBCK

SBCK

TDET

DRT[1:0]

DTM[3:0]

DADL

DDL

DDAV

TONE[4:0]

TONC[2:0]

DSP1

DSP2

DADH

DDH

DSP3

CPSQ CPCD

USEN2 USEN1 V23E

ANSE DTMFE

48

Rev. 1.3

Si2400

Table 28. Bit Mapped Register Summary (Continued)

“S”

Register Register Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Default

Binary

Register Address Name

(hex)

PDDE

SEB

SF0

SF1

SF2

SF4

SF5

SF6

SF7

SF8

SF9

0xEB

0xF0

0xF1

0xF2

0xF4

0xF5

0xF6

0xF7

0xF8

0xF9

TPD

0000_0000

0001_1100

0000_0000

0000_1111

0000_1000

0000_0000

0001_0000

—

LM

OFHK

DAA0

DAA1

DAA2

DAA4

DAA5

DAA6

DAA7

DAA8

DAA9

BTE

PDN

PDL

HBE

FDT

SQLH

FULL

ARG[2:0]

OHS

ARL[1:0]

DCT[1:0]

FJM DIAL

ATL[1:0]

DCTO

ACT

LMO

RZ

RT

VOL

FLVM

LIM

LRV[3:0]

OVL

BTD

ROV

0010_0000

Rev. 1.3

49

Si2400

S07 (MF1). Modem Functions 1

Bit

Name HDEN

Type R/W

D7

D6

BD

D5

D4

D3

D2

D1

D0

V23R

R/W

V23T

R/W

BAUD

R/W

CCITT

R/W

FSK

R/W

Reset settings = 0000_0001 (0x01)

b

Bit

Name

Function

7

HDEN

HDLC Framing.

0 = Disable.

1 = Enable.

6

5

BD

Blind Dialing.

0 = Disable.

1 = Enable (Blind dialing occurs immediately after “ATDT#” command).

V23R

V.23 Receive.*

V.23 75 bps send/600 (BAUD = 0) or 1200 (BAUD = 1) bps receive.

0 = Disable.

1 = Enable.

4

V23T

V.23 Transmit.*

V.23 600 (BAUD = 0) or 1200 (BAUD = 1) bps send/75 bps receive.

0 = Disable.

1 = Enable.

3

2

Reserved

BAUD

Read returns zero.

2400/1200 Baud Select.*

2400/1200 baud select (V23R = 0 and V23T = 0).

0 = 1200

1 = 2400

600/1200 baud select (V23R = 1 and V23T = 1).

0 = 600

1 = 1200

1

0

CCITT

FSK

CCITT/Bell Mode.*

0 = Bell.

1 = CCITT.

300 bps FSK.*

0 = Disable.

1 = Enable.

*Note: See Table 12 on page 15 for proper setting of modem protocols.

50

Rev. 1.3

Si2400

S0C (MF2). Modem Functions 2

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

CDE

R/W

CIDM

R/W

9BF

R/W

BDL

R/W

MLB

R/W

MCH

R/W

Reset settings = 0000_0000 (0x00)

b

Bit

Name

Function

CDE

7

Carrier Detect Enable.

0 = Disable.

1 = Enable GPI02 as an active low carrier detect pin (must also set SE2[3:2]

[GPIO2] = 01 ).

b

6:5

CIDM

Caller ID Monitor.

00 = Caller ID monitor disabled (Normal caller ID operation).

01 = Caller ID monitor enabled. Si2400 must detect channel seizure signal followed by

marks in order to report caller ID data.

10 = Caller ID monitor enabled. Si2400 must detect a DTMF A or D followed by marks in

order to report caller ID data.

11 = Caller ID monitor enabled. Si2400 must only detect marks in order to report caller ID

data.

4

3

Reserved

9BF

Read returns zero.

Ninth Bit Function.

Only valid if the ninth bit escape is set S15[0] (NBE).

0 = Ninth bit equivalent to ALERT.

1 = Ninth bit equivalent to HDLC EOFR.

2

1

0

BDL

MLB

MCH

Blind Dialing.

0 = Blind dialing disabled.

1 = Enables blind dialing after dial timeout register S02 (CW) expires.

Modem Loopback.

0 = Not swapped.

1 = Swaps frequency bands in modem algorithm to do a loopback in a test mode.

Miscellaneous Characters.

0 = Disables “.” and “/” character echoing.

1 = Enables “.” and “/” character echoing to indicate tone on and tone off for !7 operation.

Rev. 1.3

51

Si2400

S11 (ONHI). On-Hook Intrusion

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

DVL

R/W

AVL

R/W

Reset settings = 0100_1000 (0x48)

b

Bit

Name

Function

7:5

DVL

Differential Voltage Level.

Differential voltage level to detect intrusion event (2.75 V units.)

4:0

AVL

Absolute Voltage Level.

Absolute voltage level to detect intrusion event (2.75 V units added to 3 V.)

S12 (OFHI). Off-Hook Intrusion

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

DCL

R/W

ACL

R/W

Reset settings = 0100_0000 (0x40)

b

Bit

Name

Function

7:5

DCL

Differential Current Level.

Differential current level to detect intrusion event (3 mA units.)

4:0

ACL

Absolute Current Level.

When S13[4] (OFHD) = 0 , ACL represents the absolute current threshold used by the

b

off-hook intrusion algorithm (3 mA units added to 12 mA.)

When OFHD = 1 , see "5.5.5.Differential Algorithm #2" on page 20.

b

52

Rev. 1.3

Si2400

S13 (MF3). Modem Functions 3

Bit

D7

JID

D6

D5

OFHE OFHD ONHD

R/W R/W R/W

D4

D3

D2

D1

D0

Name

Type

BTID

R/W

CIDB

R/W

CIDU

R/W

PCM

R/W

Reset settings = 0001_0000 (0x10)

b

Bit

Name

Function

7

JID

Japan Caller ID.

0 = Disable.

1 = Enable.

6

5

BTID

BT Caller ID Wetting Pulse.

0 = Enable.

1 = Disable.

OFHE

Enable Off-Hook.

Enable off hook in current limit mode for overcurrent detection.

0 = Disable.

1 = Enable.

4

3

2

1

0

OFHD

ONHD

CIDB

CIDU

PCM

Off-Hook Intrusion Detect Method.

0 = Absolute.

1 = Differential.

On-Hook Intrusion Detect Method.

0 = Absolute.

1 = Differential.

British Telecom Caller ID Decode.

0 = Disable.

1 = Enable.

BellCore Caller ID Decode.

0 = Disable.

1 = Enable.

PCM Data Mode.

DTE rate must be ≥ 228613, and flow control must be used.

0 = Disable.

1 = Enable.

Rev. 1.3

53

Si2400

S14 (MF4). Modem Functions 4

Bit

Name MRCD

Type R/W

D7

D6

D5

D4

D3

OD

D2

D1

IND

R/W

D0

RD

UDF

R/W

TEO

R/W

AOC

R/W

NLD

R/W

Reset settings = 0000_0000 (0x00)

b

Bit

Name

Function

7

MRCD

Disable Modem Result Codes. (See S62 also.)

0 = Enables the following modem result codes:

1 = Disables the following modem result codes:

Intrusion—”i” and “I”

Line present—”l” and “L”

Flash—”f”

Ring—”R”

Register S62 can be used to individually re-enable particular result codes.

6

5

4

UDF

TEO

AOC

User Defined Frequency.

0 = Disable.

1 = Enable user defined frequency detectors in A0 and !0 modes.

TIES Escape Operation.

0 = Disable TIES escape operation.

1 = Enable TIES.

AutoOverCurrent Detection.

0 = Disables AutoOverCurrent detection.

1 = Enables AutoOverCurrent detection.

3

2

OD

Overcurrent Detected (Sticky).

No Phone Line.

NLD

This bit is sticky while off-hook if S82[3] (LCLD) = 1 , and non-sticky (status) while on-

b

hook. NLD remains sticky for 800 ms after going from off-hook to on-hook.

1

0

IND

RD

Intrusion Detected.

This bit is normally NOT sticky so that the user may monitor/poll for intrusion manually.

However, during dialing and during data mode, it is impossible to monitor/poll this bit.

Therefore, if the Si2400 is either dialing or in data mode, this bit is sticky. If triggered dur-

ing data mode, this bit will remain sticky for 800 ms after the Si2400 goes back on-hook.

Ring Detected (Sticky).

This bit is normally sticky, but is cleared when the Si2400 goes from on-hook to off-hook.

54

Rev. 1.3

Si2400

S15 (MLC). Modem Link Control

Bit

Name ATPRE VCTE

Type R/W R/W

Reset settings = 1000_0100 (0x84)

D7

D6

D5

FHGE ENGE

R/W R/W

D4

D3

D2

D1

D0

STB

R/W

BDA

R/W

NBE

R/W

b

Bit

Name

Function

7

ATPRE

Answer Tone Phase Reversal.

0 = Disable.

1 = Enable answer tone phase reversal.

6

5

VCTE

FHGE

ENGE

STB

V.25 Calling Tone.

0 = Disable.

1 = Enable V.25 calling tone.

550 Hz Guardtone.

0 = Disable.

1 = Enable 550 Hz guardtone.

4

1800 Hz Guardtone.

0 = Disable.

1 = Enable 1800 Hz guardtone.

3

Stop Bits.

0 = 1 stop bit.

1 = 2 stop bits.

2:1

BDA

Bit Data.

00 = 6 bit data.

01 = 7 bit data.

10 = 8 bit data.

11 = 9 bit data.

0

NBE

Ninth Bit Enable.

0 = Disable.

1 = Enable ninth bit as Escape and ninth bit function (register C).

Rev. 1.3

55

Si2400

S1F (ARM3). Alarm 3 (!7 Mode Only)

Bit

D7

D6

D5

D4

D3

D2

IMT

R/W

D1

D0

Name

Type

KOT

R/W

Reset settings = 0010_1101 (0x2D)

b

Bit

Name

Function

7:5

KOT

Kissoff Timeout.

1 s units. Maximum 7 s.

4:0

IMT

Intermessage Timing.

500 ms units. Maximum 8 s.

Note: S1F is reconfigured as Alarm 3, a bit-mapped register, in !7 mode only. In all other modes, S1F is ATTD (Answer Tone

to Transmit Delay).

56

Rev. 1.3

Si2400

S33 (MDMO). Modem Override

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

DON

R/W

DOF

R/W

NAT

R/W

TSAC

R/W

Reset settings = 1000_0000 (0x80)

b

Bit

7

Name

Reserved

DON

Function

Read returns one.

6

On-Hook Intrusion Detect.

0 = Enable.

1 = Disable*.

5

DOF

Off-Hook Intrusion Detect.

0 = Enable.

1 = Disable.

4:2

1

Reserved

NAT

Read returns zero.

No Answer Tone.

0 = Disable.

1 = Enable no answer tone fast handshake.

0

TSAC

Transmit Scrambler Active.

0 = Disable.

1 = Force transmit scrambler active once connected.

*Note: When the Si2400 is on hook, the on-hook intrusion detector might not be immediately disabled by only setting the

S33[6] (DON) = 1 (S33 = 0xCX, X indicates an otherwise appropriate value.) In order to guarantee that the result

b

codes and the updating of S14[2] (NLD) and S14[1] (IND) are immediately disabled, ATS33=CX must be followed by

ATSD1=00S14=X0.

Rev. 1.3

57

Si2400

S36 (ARM1). Alarm 1 (!7 Mode Only)

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

POF

R/W

PON

R/W

IDKT

R/W

IT

R/W

Reset settings = 0011_0000 (0x30)

b

Bit

Name

Function

7:6

POF

Pulse Off Time.

00 = 25 ms.

01 = 50 ms.

10 = 65 ms.

11 = Use S2C register.

5:4

3:2

PON

IDKT

Pulse On Time.

00 = 25 ms.

01 = 50 ms.

10 = 65 ms.

11 = Use S2B register.

Intermessage Delay and Kissoff Timeout.

This register field defines two parameters. The Intermessage Delay defines the time the Si2400

waits prior to sending a subsequent message. The Kissoff Timeout defines the time the Si2400

waits for a Kissoff Tone prior to declaring that there is no kissoff tone detected.

00 = Intermessage Delay is measured relative to the end of Kissoff and it is a fixed delay

of 2.4 s. The Kissoff Timeout is measured relative to the end of Kissoff and it is a fixed

value of 2 s.

01 = Intermessage Delay is measured relative to the end of Kissoff and it is determined by

S1F[4:0] (IMT). The Kissoff Timeout is measured relative to the end of Kissoff and it is deter-

mined by S1F[7:5] (KOT).

10 = Intermessage Delay is measured relative to the end of the previous message and it is a

fixed delay of 3.4 s. The Kissoff Timeout is measured relative to the end of Kissoff and it is a

fixed value of 2 s.

11 = Intermessage Delay is measured relative to the end of the previous message and it is

determined by S1F[7:5] (KOT). The Kissoff Timeout is measured relative to the end of Kissoff

and it is determined by S1F[7:5] (KOT).

1:0

IT

Interdigit Timing.

The controlled timing between the pulse digits.

00 = The timing between the end of a digit to the start of the next digit is fixed at 660 ms.

01 = The timing between the end of a digit to the start of the next digit is defined by the S2D

register.

10 = The timing between the start of a digit to the start of the next digit is fixed at 800 ms.

11 = The timing between the start of a digit to the start of the next digit is defined by the S2D

register.

Note: S36 is reconfigured as Alarm 1, a bit-mapped register, in !7 mode only. In all other modes, S36 is SKDTL (Second

Kissoff Tone Detect Length).

58

Rev. 1.3

Si2400

S38 (ARM2). Alarm 2 (!7 Mode Only)

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

DBD

R/W

DCF

R/W

HMT

R/W

HF

R/W

Reset settings = 0011_1000 (0x38)

b

Bit

Name

Function

7

DBD

Delay Before Data.

Time the Si2400 waits prior to transmitting data, relative to the end of the handshake

tone.

0 = 300 ms.

1 = Use S2E (RTCT) register contents.

6:5

4:2

DCF

HMT

Data Carrier Frequency.

Frequency that the Si2400 will use to transmit.

00 = User programmed. This is accomplished by accessing DSP register 5 prior to using

the !7 command.

01 = 1800 Hz.

10 = 1900 Hz.

11 = 1850 Hz.

Handshake Minimum Time.

The minimum required tone length for a handshake tone or a kissoff tone.

000 = 53 ms.

001 = 160 ms.

010 = 320 ms.

011 = 480 ms.

100 = 640 ms.

101 = 800 ms.

110 = 960 ms.

111 = 1120 ms.

1:0

HF

Handshake Frequency.

The frequency that the Si2400 detects as Handshake and Kissoff Tone.

00 = User-defined frequency detectors must be programmed prior to using the !7

command. See DSP Registers.

01 = 1400 Hz only.

10 = 2300 Hz only.

11 = 1400 Hz or 2300 Hz.

Note: S38 (ALARM2) is used in !7 mode only.

Rev. 1.3

59

Si2400

S3C (CIDG). Caller ID Gain

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

CIDG

R/W

Reset settings = 0000_0100 (0x04)

b

Bit

7:3

2:0

Name

Reserved

CIDG

Function

Read returns 0.

Caller ID Gain.

The Si2400 dynamically sets the On-Hook Analog Receive Gain SF4[6:4] (ARG) to

CIDG during a caller ID event (or continuously if S0C[6:5] (CIDM = 11 ). This field should

b

be set prior to caller ID operation.

000 = 7 dB

001 = 6 dB

010 = 4.8 dB

011 = 3.5 dB

100 = 2.0 dB

101 = 0 dB

110 = –2.0 dB

111 = –6.0 dB

60

Rev. 1.3

Si2400

S62 (RC). Result Codes Override

Bit

D7

D6

D5

D4

D3

D2

IR

D1

D0

RR

Name

Type

CLD

R/W

OCR

R/W

LLC

R/W

WOR

R/W

FLS

R/W

NLR

R/W

Reset settings = 0000_0000 (0x00)

b

Bit

Name

Function

7

CLD

Carrier Loss Detector.

0 = Default.

1 = Caller ID sensitivity can be increased by 5 dB. When CLD = 1, the host is responsi-

ble for terminating caller ID reception by asserting an escape and issuing the ATH com-

mand.

Note: This bit also controls the carrier loss detection of non-caller ID modes of operation.

Therefore, the host must set CLD = 0 prior to answering a call via “ATA” or initiating a call

via “ATDT” or “ATDP”.

6

5

OCR

LLC

Overcurrent Result Code (“x”).

0 = Enable.

1 = Disable.

Low Loop Current (required for CTR21 operation).

This feature only works when SDF ≠ 0x00.

0 = Disable.

1 = Enable.

4

3

2

1

0

WOR

FLS

IR

Wake-On-Ring Alert.

0 = Alert is not asserted upon a wake-on-ring event.

1 = Alert is asserted upon a wake-on-ring event SE2[7:6] (GPIO4) = 11 .

b

Hookswitch Flash Result Code (“f”).*

0 = Disable.

1 = Enable.

Intrusion Result Code (“I” and “i”).*

0 = Disable.

1 = Enable.

NLR

RR

No Phone Line Result Code (“L” and “l”).*

0 = Disable.

1 = Enable.

Ring Result Code (“R”).*

0 = Disable.

1 = Enable.

*Note: S62[3] (FLS), S62[2] (IR), S62[1] (NLR), and S62[0] (RR) only apply if S14[7] (MRCD) = 1.

Rev. 1.3

61

Si2400

S82 (IST). Intrusion

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

IST

LCLD

R/W

IB

R/W

Reset settings = 0000_0000 (0x00)

b

Bit

Name

Function

7:4

IST

Intrusion Settling Time.

0000 = IST equals 1 second.

Delay between when the ISOmodem goes off-hook and the off-hook intrusion algorithm

begins (250 ms units).

3

LCLD

IB

Loop Current Loss Detect.

0 = Disable.

1 = Enables the reporting of “I” and “L” result codes while off-hook. Will assert ALERT if

GPIO4 (SE2[7:6]) is enabled as ALERT. Will assert NLD (S14[2]).

2:1

Intrusion Blocking.

This feature only works when SDF ≠ 0x00. Defines the method used to block the off-hook

intrusion algorithm from operating after dialing has begun.

00 = No intrusion blocking.

01 = Intrusion disabled from start of dial to end of dial.

10 = Intrusion disabled from start of dial to register S29 time out.

11 = Intrusion disabled from start of dial to carrier detect or to “N” or “n” result code.

0

Reserved

Read returns 0.

SDF (DGSR). Intrusion Deglitch

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

DGSR

R/W

Reset settings = 0000_0000 (0x00)

b

Bit

7

Name

Reserved

DGSR

Function

Read returns zero.

6:0

Deglitch Sample Rate.

Sets the sample rate for the deglitch algorithm and the off-hook intrusion algorithm

(40 ms units).

0000000 = Disables the deglitch algorithm, and sets the off-hook intrusion sample

rate to 200 ms and delay between compared samples to 800 ms.

62

Rev. 1.3

Si2400

SE0 (CF1). Chip Functions 1

Bit

D7

D6

D5

D4

D3

ND

D2

D1

SD

D0

Name

Type

ICTS

R/W

Reset settings = 0010_0010 (0x22)

b

Bit

7:6

5

Name

Reserved

ICTS

Function

Read returns zero.

Invert CTS pin.

0 = Inverted (CTS).

1 = Normal (CTS).

4

3

Reserved

ND

Read returns zero.

0 = 8N1.

1 = 9N1 (hardware UART only).

2:0

SD

Serial Dividers.

000 = 300 bps serial link.

001 = 1200 bps serial link.

010 = 2400 bps serial link.

011 = 9600 bps serial link.

100 = 19200 bps serial link.

101 = 228613 bps serial link (0.8% error to 230400 bps).

110 = 245760 bps serial link.

111 = 307200 bps serial link.

Rev. 1.3

63

Si2400

SE1 (CLK1). Clock 1

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

MCKR

R/W

CLKD

R/W

Reset settings = 0000_0111 (0x07)

b

Bit

Name

Function

7:6

MCKR

Microcontroller Clock Rate.

0 = Fastest 9.8304 MHz.

1 = 4.9152 MHz.

2 = 2.4576 MHz.

3 = Reserved.

Note: MCKR must be set to 0 when the UART DTE rate is set to 228613 or greater

(SE0[2:0] (SD) = 101 , 110_bor 111 ).

b

5

Reserved

CLKD

Read returns zero.

4:0

CLK_OUT Divider.

00000 = Disable CLK_OUT pin.

CLK_OUT = 78.6432/(CLKD + 1) MHz.

00111 CLK_OUT = 9.8304 MHz.

b

64

Rev. 1.3

Si2400

SE2 (GPIO). General Purpose Input/Output

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

GPIO4

R/W

GPIO3

R/W

GPIO2

R/W

GPIO1

R/W

Reset settings = 0000_0000 (0x00)

b

Bit

Name

Function

7:6

GPIO4

GPIO4.

00 = Digital input.

01 = Digital output (relay drive).

10 = Analog input.

11 = ALERT function triggered by loss of carrier (always), V.23 reversal (always), wake-

on-ring S62[4] (WOR), parallel phone intrusion S33[5] (DOF), or loss of loop current

S82[3] (LCLD).

5:4

3:2

1:0

GPIO3

GPIO2

GPIO1

GPIO3.

00 = Digital input.

01 = Digital output (relay drive).

01 = Analog input.

11 = ESCAPE function (digital input).

GPIO2*.

00 = Digital input.

01 = Digital output (relay drive; also used for CD function).

10 = Analog input.

11 = Reserved.

GPIO1*.

00 = Digital input.

01 = Digital output (relay drive).

10 = Analog input.

11 = Reserved.

*Note: To be used as analog input or GPIO pins; SE4[3] (GPE) and SE4[0] (TRSP) must both equal zero.

Rev. 1.3

65

Si2400

SE3 (GPD). GPIO Data

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

AING

R/W

GPD4

R/W

GPD3

R/W

GPD2

R/W

GPD1

R/W

Reset settings = 0000_0000 (0x00)

b

Bit

Name

Function

7:6

AING

AIN Gain Bits.

00 = 0 dB

01 = 6 dB

10 = 2.5 dB

11 = 12 dB

5:4

3

Reserved

GPD4

Read returns zero.

GPIO4 Data.

0

1

2

GPD3

GPIO3 Data.

0

1

0

GPD2

GPD1

GPIO2 Data.

0

1

GPIO1 Data.

0

1

66

Rev. 1.3

Si2400

SE4 (CF5). Chip Functions 5

Bit

Name NBCK

Type

D7

D6

SBCK

R

D5

D4

D3

D2

D1

D0

DRT

R/W

GPE

R/W

APO

R/W

TRSP

R/W

R

Reset settings = 0000_0000 (0x00)

b

Bit

7

Name

NBCK

SBCK

DRT

Function

9600 Baud Clock (Read Only).

600 Baud Clock (Read Only).

Data Routing (See Figure 10).

6

5:4

00 = Data mode, DSP output transmitted to line, line received by DSP input.

01 = Voice mode, selected AIN transmitted to line, line received by AOUT.

10 = Loopback mode, RXD through microcontroller (DSP) to TXD. AIN looped to AOUT.

11 = Codec mode, data from DSPOUT to AOUT, AIN to DSPIN.

3

GPE*

GPIO1 Enable.

0 = Disable.

1 = Enable GPIO1 to be HDLC end-of-frame flag.

2

1

Reserved

APO

Read returns zero.

Analog Power On.

0 = Disable.

1 = Power on analog ADC and DAC.

0

TRSP*

TXD2/RXD2 Serial Port.

0 = Disable.

1 = Enable TXD2/RXD2 serial port so that RXD2 is GPIO1 and TXD2 is GPIO2.

*Note: GPE and TRSP are mutually exclusive. Only one can be set at any one time, and they override the settings in registers

GPIO2 and GPIO1. Once TXD2 and RXD2 are enabled through TRSP = 1 , the primary serial port TXD and RXD no

b

longer function and pins TXD2 and RXD2 control the Si2400. This feature allows a second microcontroller to control

the Si2400.

Rev. 1.3

67

Si2400

SE5 (DSP1). (SE8 = 0x02) Read Only Definition

Bit

Name DDAV

Type

D7

D6

TDET

R

D5

D4

D3

D2

TONE

R

D1

D0

R

Reset settings = 0000_0000 (0x00)

b

Bit

7

Name

DDAV

TDET

Function

DSP Data Available.

Tone Detected.

6

Indicates a TONE (any of type 0–25 below) has been detected.

0 = Not detected.

1 = Detected.

5

Reserved

TONE

Read returns zero.

4:0

Tone Type Detected.

When TDET goes high, TONE indicates which tone has been detected from the following:

TONE

Tone Type

Priority

1

00000–01111 DTMF 0–15 (DTMFE = 1) See Table 23 on page 39

1

2

3

4

6

5

6

2

10000

10001

10010

10011

10100

10101

10110

10111

11000

11001

Answer tone detected 2100 Hz (ANSE = 1)

Bell 103 answer tone detected 2225 Hz (ANSE = 1)

V.23 forward channel mark 1300 Hz (V23E = 1)

V.23 backward channel mark 390 Hz (V23E = 1)

User defined frequency 1 (USEN1 = 1)

User defined frequency 2 (USEN1 = 1)

Call progress filter A detected

User defined frequency 3 (USEN2 = 1)

User defined frequency 4 (USEN2 = 1)

Call progress filter B detected

3

4

5

Notes:

1. SE6[0] (DTMFE) SE8 = 0x02.

2. SE6[1] (ANSE) SE8 = 0x02.

3. SE6[2] (V23E) SE8 = 0x02.

4. SE6[3] (USEN1) SE8 = 0x02.

5. SE6[4] (USEN2) SE8 = 0x02.

68

Rev. 1.3

Si2400

SE5 (DSP2). (SE8 = 0x02) Write Only Definition

Bit

D7

D6

D5

D4

D3

D2

D1

TONC

W

D0

Name

Type

DTM

W

Reset settings = 0000_0000 (0x00)

b

Bit

Name

Function

7

Reserved

DTM

Always write zero.

6:3

2:0

DTMF tone (0–15) to transmit when selected by TONC = 001 . See Table 23 on page 39.

b

TONC

Tone

Tone Type

000

001

010

011

100

101

110

Mute

DTMF

2225 Hz Bell mode answer tone with phase reversal

2100 Hz CCITT mode answer tone with phase reversal

2225 Hz Bell mode answer tone without phase reversal

2100 Hz CCITT mode answer tone without phase reversal

User-defined programmable frequency tone (UFRQ)

(see Table 24 on page 40, default = 1700 Hz)

1300 Hz V.25 calling tone

111

Rev. 1.3

69

Si2400

SE6 (DSP3). (SE8 = 0x02) Write Only Definition

Bit

Name CPSQ CPCD

Type

Reset settings = 0000_0000 (0x00)

D7

D6

D5

D4

D3

D2

D1

D0

USEN2 USEN1 V23E

ANSE DTMFE

W

b

Bit

Name

Function

7

CPSQ

0 = Disable.

1 = Enables a squaring function on the output of filter B before the input to A (cascade

only).

6

CPCD

0 = Call progress filter B output is input into call progress filter A. Output from fil-

ter A is used in the detector.

1 = Cascade disabled. Two independent fourth order filters available (A and B). The

largest output of the two is used in the detector.

5

4

Reserved

USEN2

0 = Disable.

1 = Enable the reporting of user defined frequency tones 3 and 4 through TONE.

3

2

1

0

USEN1

V23E

0 = Disable.

1 = Enable the reporting of user defined frequency tones 1 and 2.

0 = Disable.

1 = Enable the reporting of V.23 tones, 390 Hz and 1300 Hz.

0 = Disable.

1 = Enable the reporting of answer tones.

0 = Disable.

ANSE

DTMFE

1 = Enable the reporting of DTMF tones.

SEB (TPD). Timer and Power Down

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

PDDE

R/W

Reset settings = 0000_0000 (0x00)

b

Bit

7:4

3

Name

Reserved

PDDE

Function

Read returns zero.

Power Down DSP Engine.

0 = Power on

1 = Power down

2:0

Reserved

Read returns zero.

70

Rev. 1.3

Si2400

SF0 (DAA0). DAA Low Level Functions 0

Bit

D7

D6

D5

D4

D3

D2

D1

LM

D0

Name

Type

OFHK

R/W

Reset settings = 0000_0000 (0x00)

b

Bit

7:2

1

Name

Reserved

LM

Function

Read returns zero.

1,2

Hook Control/Status.

OFHK LM

LM0

Line Status Mode

On-hook

On-hook line monitor mode (Si3015 compatible)

Off-hook

0

OFHK

0

1

0

1

0

1

0

Else Reserved

Notes:

1. See Register F7 on page 76 for LM0.

2. Under normal operation, the Si2400 internal microcontroller will automatically set these bits appropriately.

Rev. 1.3

71

Si2400

SF1 (DAA1). DAA Low Level Functions 1

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

BTE

R/W

PDN

R/W

PDL

R/W

HBE

Reset settings = 0001_1100 (0x1C)

b

Bit

Name

Function

7

BTE

Billing Tone Enable.

When the Si3015 detects a billing tone, SF9[3] (BTD) is set.

0 = Disable.

1 = Enable.

6

5

PDN

PDL

Power Down.

0 = Normal operation.

1 = Powers down the Si2400.

Power Down Line-Side Chip (typically only used for board level debug.)

0 = Normal operation. Program the clock generator before clearing this bit.

1 = Places the Si3015 in lower power mode.

4:3

2

Reserved

HBE

Do Not Modify

Hybrid Transmit Path Connect.

0 = Disable.

1 = Enable.

1:0

Reserved

Do Not Modify

SF2 (DAA2). DAA Low Level Functions 2

Bit

D7

D6

D5

D4

D3

FDT

R

D2

D1

D0

Name

Type

Reset settings = 0000_0000 (0x00)

b

Bit

7:4

3

Name

Reserved

FDT

Function

Read only.

Frame Detect (Typically only used for board-level debug.)

1 = Indicates link frame lock has been established.

0 = Indicates link frame lock has not been established.

2:0

Reserved

72

Rev. 1.3

Si2400

SF4 (DAA4). DAA Low Level Functions 4

Bit

Name SQLH

Type R/W

D7

D6

D5

D4

D3

D2

D1

D0

ARG

R/W

ARL

R/W

ATL

R/W

Reset settings = 0000_1111 (0x0F)

b

Bit

Name

Function

7

SQLH

Ring Squelch.

If the host implements a manual ring detect (bypassing the Si2400 micro), this bit must

be set, then cleared following a polarity reversal detection. Used to quickly recover offset

on RNG1/2 pins after polarity reversal.

0 = Normal.

1 = Squelch.

6:4

ARG

Analog Receive Gain.

Off-Hook

On-Hook

001 = 6 dB

010 = 4.8 dB

011 = 3.5 dB

1xx = 2.0 dB

000 = 0 dB gain 000 = 7 dB

001 = 3 dB gain

010 = 6 dB gain

011 = 9 dB gain

1xx = 12 dB gain

3:2

1:0

ARL

ATL

AOUT Receive—Path Level.

DAA receive path signal AOUT gain.

00 = 0 dB

01 = –6 dB

10 = –12 dB*

11 = Mute

AOUT Transmit—Path Level.

DAA transmit path signal AOUT gain.

00 = –18 dB

01 = –24 dB

10 = –30 dB*

11 = Mute

Rev. 1.3

73

Si2400

SF5 (DAA5). DAA Low Level Functions 5

Bit

Name FULL

Type R/W

D7

D6

D5

D4

D3

D2

D1

RZ

D0

RT

DCTO

R/W

OHS

R/W

ACT

R/W

DCT

R/W

Reset settings = 0000_1000 (0x08)

b

Bit

Name

Function

7

FULL

Full Scale.

0 = Si3015 ADC/DAC full scale > –1 dBm.

1 = Si3015 ADC/DAC full scale > 3.2 dBm.

This bit changes the full scale of the ADC and DAC from –1 dBm min. to 3.2 dBm min. In

order to use this bit, the R2 resistor must be changed from 402 Ω to 243 Ω and ACT

(SF5, bit 4) must be set to 0. This bit is intended for use only in voice communications

and may be used in PCM modes.

6

DCTO

DC Termination Off.

0 = Normal operation. The OFF bit must always be set to 0 when on-hook.

1 = DC termination disabled and the device presents an 800 Ω dc impedance to the line

which is used to enhance operation with an off-hook parallel phone.

5

4

OHS

ACT

DCT

On-Hook Speed (See Table 13 and “Appendix A—DAA Operation”).

0 = The Si2400 will execute a fast on-hook.

1 = The Si2400 will execute a slow, controlled on-hook.

AC Termination (See Table 13 and “Appendix A—DAA Operation”).

0 = Real impedance.

1 = Complex impedance.

3:2

DC Termination Voltage (See Table 13 and “Appendix A—DAA Operation”).

00 = Low Voltage Mode (transmit level = –5 dBm).

01 = Japan mode (transmit level = –3 dBm).

10 = USA mode (transmit level = –1 dBm).

11 = CTR21/France current limit mode (transmit level = –1 dBm).

1

0

RZ

RT

Ringer Impedance.

0 = Maximum (high) ringer impedance.

1 = Synthesize ringer impedance.

Ringer Threshold Select.

Used to satisfy country requirements on ring detection. Signals below the lower level will

not generate a ring detection; signals above the upper level are guaranteed to generate

a ring detection.

0 = 11 to 22 VRMS.

1 = 17 to 33 V

.

RMS

74

Rev. 1.3

Si2400

SF6 (DAA6). DAA Low Level Functions 6

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

FJM

R/W

DIAL

VOL

R/W

FLVM

R/W

Reset settings = 0000_0000 (0x00)

b

Bit

7:4

3

Name

Reserved

FJM

Function

Read returns zero.

Force Japan DC Termination.

0 = Normal mode.

1 = Force Japan dc termination.

2

DIAL

DTMF Dialing Mode.

This bit should be set during DTMF dialing in CTR21 mode if SDB (LVCS) < 12.

0 = Normal operation.

1 = Increase headroom for DTMF dialing.

1

0

VOL

Line Voltage Adjust.

0 = Nominal.

1 = Decreases dc termination voltage.

FLVM

Force Low Voltage Mode.

When SF5[3:2] (DCT) = 10 (FCC mode), setting FLVM will force the Low Voltage mode

b

(see DCT = 00) while allowing for a transmit level of –1 dBm.

0 = Disable.

1 = Enable.

Rev. 1.3

75

Si2400

SF7 (DAA7). DAA Low Level Functions 7

Bit

D7

D6

D5

D4

D3

LIM

R/W

D2

D1

D0

Name

Type

LM0

R/W

Reset settings = 0001_0000 (0x10)

b

Bit

7:5

4

Name

Reserved

LM0

Function

Read returns zero.

See LM0 in Register F0 page 71.

0

1

3

LIM

Current-Limiting Adjust Value.

0 = Disable.

1 = Enable (CTR21 mode).

2:0

Reserved

Read returns zero.

SF8 (DAA8). DAA Low Level Functions 8

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Name

Type

LRV

R

Bit

Name

Function

7:4

LRV

Line-Side Chip Revision Number.

1001 = Si3015 Rev A

1010 = Si3015 Rev B

1011 = Si3015 Rev C

1100 = Si3015 Rev D

3:0

Reserved

Read returns indeterministic.

76

Rev. 1.3

Si2400

SF9 (DAA9). DAA Low Level Functions 9 Read Only

Bit

D7

D6

OVL

R

D5

D4

D3

BTD

R

D2

D1

ROV

R

D0

Name

Type

Reset settings = 0010_0000 (0x20)

b

Bit

7

Name

Reserved

OVL

Function

Read returns zero.

6

Receive Overload (see “Appendix A—DAA Operation”).

Same as ROV, except non-sticky.

5:4

3

Reserved

BTD

Do Not Modify.

Billing Tone Detect (sticky). (See “Appendix A—DAA Operation”.)

0 = No billing tone detected.

1 = Billing tone detected.

2

1

Reserved

ROV

Read returns zero.

Receive Overload (sticky) (see “Appendix A—DAA Operation”).

0 = No excessive level detected.

1 = Excessive input level detected.

0

Reserved

Read returns zero.

Rev. 1.3

77

Si2400

APPENDIX A—DAA OPERATION

EN55022 and CISPR-22 Compliance

Introduction

Compliance to the EN55022:1998 standard will be

necessary to conform to the European Union's EMC

Directive. Adherence to this standard will be necessary

to display the CE mark on designs intended for sale in

the EU. The deadline for EN55022 and CISPR-22

compliance is August 1, 2003. However, some non-

European countries currently require compliance to the

CISPR-22 specification. The typical schematic

(Figure 3) and global bill of materials (BOM) (page 11)

contained in this data sheet is designed to be compliant

to the above mentioned standards. It should be noted

that L1, L2, R31, R32, C38, and C39 are only necessary

for those products which are intended for sale in the

European Union or require CISPR-22 compliance. If this

is not the target market then L1 and L2 can be replaced

with 0 Ω resistors and R31, R32, C38, and C39 need

not be populated.

This section describes the detailed functionality of the

integrated DAA included in the Si2400 chipset. This

specific functionality is generally transparent to the user

when using the on-chip controller in the Si2400 modem.

When bypassing the on-chip controller, the low-level

DAA functions of the Si3015 described in this section

can be controlled through S registers.

DAA Isolation Barrier

The Si2400 chipset consists of the Si3015 line-side

device and the Si2400 modem device. The Si2400

achieves an isolation barrier through a low-cost, high-

voltage capacitor in conjunction with Silicon

Laboratories’ proprietary signal processing techniques.

These techniques eliminate any signal degradation due

to capacitor mismatches, common mode interference,

or noise coupling. As shown in Figure 3 on page 10, the

C1, C4, C24, and C25 capacitors isolate the Si2400

(DSP-side) from the Si3015 (line-side). All transmit,

receive, and control data are communicated through

this barrier.

While this population option achieves EN55022 and

CISPR-22 compliance, there are several system

dependent and country dependent issues worth

considering. The first relates to the direct current

resistance (DCR) of the inductors. If the selected

inductors have a DCR of less than 3 Ω each, then

countries which require 300 Ω or less of dc resistance at

TIP and RING with 20 mA of loop current can be

satisfied with the Japan dc termination mode (SF5[3:2]

Emissions/Immunity

The Si2400 chipset and recommended DAA schematic

is fully compliant with and passes all international

electromagnetic emissions and conducted immunity

tests (includes FCC part 15,68; EN50082-1). Careful

attention to the Si2400 bill of materials (page 11),

schematic (Figure 3 on page 10), and layout guidelines

(included in the Si2400URT-EVB data sheet) will ensure

compliance with these international standards. In

designs with difficult layout constraints, the addition of

the C22 and C30 capacitors to the C24 and C25

[DCT] = 01 ). If the selected inductors have a DCR of

b

greater than 3 Ω but less than 8 Ω each, then low

voltage dc termination mode (DCT = 00) must be used

to satisfy the above requirement. In either case, Silicon

Laboratories strongly recommends users of the

ISOmodem adhere to the section “DC Termination

Considerations” for dc termination requirements.

recommended capacitors may improve modem The second consideration relates to the power supply of

performance on emissions and conducted immunity.

the target system. The recommended values for L1, L2,

R31, R32, C38, and C39 assume that the target system

provides a direct current connection between the target

system's reference ground (Si2400 GND) and an

external ground (often the third prong of a power plug).

If there is no direct connection between the reference

ground and external ground, then smaller inductor

values are possible. It should be understood that this

consideration is system dependent, and the impedance

between the system ground and the external ground in

the range of 500 kHz and 10 MHz should be well

known. Please contact a Silicon Laboratories technical

representative for further assistance in analyzing or

testing systems for this consideration.

Also, under some layout conditions, C22 and C30 may

improve the immunity to telephone line transients. This

is most important for applications that use the voice

codec feature of the Si2400. Because line transients are

infrequent and high voltage in nature, they tend to be

more problematic in voice applications than in data

applications. An occasional pop in a voice application is

quite noticeable, whereas occasional bit errors are

easily corrected in a modem connection with an error-

correction protocol.

78

Rev. 1.3

Si2400

Japan mode DCT = 01 , shown in Figure 16, is a lower

DC Termination

b

voltage mode and supports a transmit full scale level of

–2.71 dBm. Higher transmit levels for DTMF dialing are

also supported. See "DTMF Dialing" on page 80. The

low voltage requirement is dictated by countries such as

Japan and Malaysia.

The Si2400 has four programmable dc termination

modes which are selected with SF5[3:2] (DCT).

FCC mode (DCT = 10 ), shown in Figure 14, is the

b

default dc termination mode and supports a transmit full

scale level of –1 dBm at TIP and RING. This mode

meets FCC requirements in addition to the requirements

of many other countries.

Japan DCT Mode

10.5

10

9.5

9

FCC DCT Mode

12

8.5

8

11

10

9

7.5

7

6.5

6

8

5.5

.01 .02 .03 .04 .05 .06 .07 .08 .09 .1 .11

7

Loop Current (A)

6

Figure 16. Japan Mode I/V Characteristics

.01 .02 .03 .04 .05 .06 .07 .08 .09 .1 .11

Low Voltage mode (DCT = 00 ), shown in Figure 17, is

b

Loop Current (A)

the lowest line voltage mode supported on the Si2400,

with a transmit full scale level of –5 dBm. Higher

transmit levels for DTMF dialing are also supported.

See “DTMF Dialing”. This low voltage mode is offered

for situations that require very low line voltage

operation. It is important to note that this mode should

only be used when necessary, as the dynamic range will

be significantly reduced and thus the ISOmodem will

not be able to transmit or receive large signals without

clipping them.

Figure 14. FCC Mode I/V Characteristics

CTR21 mode DCT = 11 , shown in Figure 15, provides

b

current limiting while maintaining a transmit full scale

level of –1 dBm at TIP and RING. In this mode, the dc

termination will current limit before reaching 60 mA.

CTR21 DCT Mode

45

40

Low Voltage Mode

10.5

35

30

25

20

15

10

9.5

9

8.5

8

7.5

7

5

.015 .02 .025 .03 .035 .04 .045 .05 .055 .06

6.5

6

Loop Current (A)

5.5

Figure 15. CTR21 Mode I/V Characteristics

.01 .02 .03 .04 .05 .06 .07 .08 .09 .1 .11

Loop Current (A)

Figure 17. Low Voltage Mode I/V

Characteristics

Rev. 1.3

79

Si2400

termination mode (DCT = 01 ) or the Low Voltage

AC Termination

b

termination mode (DCT = 00 ). SF6[3] (FJM) and

b

The Si2400 has two ac termination impedances,

selected with SF5[4] (ACT).

SF6[0] (FLVM) have no effect in any other termination

mode other than the FCC dc termination mode.

ACT = 0 is a real, nominal 600 Ω termination which

b

Pulse Dialing

satisfies the impedance requirements of FCC part 68,

JATE, and other countries. This real impedance is set

by circuitry internal to the Si2400 chipset as well as the

resistor R2 connected to the Si3015 REXT pin.

Pulse dialing is accomplished by going off and on hook

to generate make and break pulses. The nominal rate is

10 pulses per second. Some countries have very tight

ACT = 1 is a complex impedance which satisfies the specifications for pulse fidelity, including make and

b

impedance requirements of Australia, New Zealand, break times, make resistance, and rise and fall times. In

South Africa, CTR21 and some European NET4 a traditional solid-state dc holding circuit, there are a

countries such as the UK and Germany. This complex number of issues in meeting these requirements.

impedance is set by circuitry internal to the Si2400

chipset as well as the network connected to the Si3015

on-hook and off-hook transients to maintain pulse

REXT2 pin.

The Si2400 dc holding circuit has active control of the

dialing fidelity.

Spark quenching requirements in countries such as

Ringer Impedance

Italy, Netherlands, South Africa and Australia deal with

The ring detector in a typical DAA is ac coupled to the

the on-hook transition during pulse dialing. These tests

line with a large, 1 µF, 250 V decoupling capacitor. The

provide an inductive dc feed, resulting in a large voltage

ring detector on the Si2400 is also capacitively coupled

spike. This spike is caused by the line inductance and

to the line, but it is designed to use smaller, less

the sudden decrease in current through the loop when

expensive 560 pF capacitors. Inherently, this network

going on-hook. The traditional way of dealing with this

produces a very high ringer impedance to the line on

problem is to put a parallel RC shunt across the

the order of 800 to 900 kΩ. This value is acceptable for

hookswitch relay. The capacitor is large (~1 µF, 250 V)

most countries, including FCC and CTR21.

and expensive. In the Si2400, SF5[6:5] (OHS) can be

Several countries, including Poland, South Africa and

used to slowly ramp down the loop current to pass these

South Korea, require a maximum ringer impedance. For

tests without requiring additional components.

Poland, South Africa and South Korea, the maximum

ringer impedance specification can be met with an

internally synthesized impedance by setting SF5[1]

Billing Tone Detection

“Billing tones” or “metering pulses” generated by the

central office can cause modem connection difficulties.

The billing tone is typically either a 12 KHz or 16 KHz

signal and is sometimes used in Germany, Switzerland,

and South Africa. Depending on line conditions, the

billing tone may be large enough to cause major modem

errors. The Si2400 chipset can provide feedback when

a billing tone occurs and when it ends.

(RZ) = 1 .

b

DTMF Dialing

In CTR21 dc termination mode, set SF6[2] (DIAL) = 1

b

during DTMF dialing if SDB (LVCS) ≤ 11. Setting this bit

increases headroom for large signals. This bit should

only be used during dialing and if SDB (LVCS) < 11.

In Japan dc termination mode (SF5[3:2] (DCT) = 01 ),

the ISOmodem attenuates the transmit output by 1.7 dB

to meet headroom requirements. Similarly, in Low

b

Billing tone detection is enabled by setting SF1[7]

(BTE) = 1 . Billing tones less than 1.1 V on the line

b

PK

will be filtered out by the low pass digital filter on the

Si2400. SF9[1] (ROV) is set when a line signal is

Voltage mode (DCT = 00 ), the ISOmodem attenuates

b

the transmit output by 4 dB. However, when DTMF

dialing is desired in these modes, this attenuation must

be removed. This is achieved by entering the FCC dc

greater than 1.1 V , indicating a receive overload

PK

condition. SF9[3] (BTD) is set when a line signal (billing

tone) is large enough to excessively reduce the line-

derived power supply of the line-side device (Si3015).

When the BTD bit is set, the dc termination is changed

to an 800 Ω dc impedance. This ensures minimum line

voltage levels even in the presence of billing tones.

termination mode and setting SF6[3] (FJM) = 1 or

b

SF6[0] (FLVM) = 1. When in the FCC dc termination

modes, these bits will enable the respective lower loop

current termination modes without the associated

transmit attenuation. Increased distortion may be

observed, which is acceptable during DTMF dialing.

After DTMF dialing is complete, the attenuation should

be enabled by returning to either the Japan dc

The OVL bit should be polled following a billing tone

detection. When the OVL bit returns to zero, indicating

that the billing tone has passed, the BTE bit should be

written to zero to return the dc termination to its original

80

Rev. 1.3

Si2400

state. It will take approximately one second to return to

normal dc operating conditions. The BTD and ROV bits

are sticky, and they must be written to zero to be reset.

After the BTE, ROV, and BTD bits are all cleared, the

BTE bit can be set to reenable billing tone detection.

C1

C2

Certain line events, such as an off-hook event on a

parallel phone or a polarity reversal, may trigger the

ROV or the BTD bits, after which the billing tone detector

must be reset. The user should look for multiple events

before qualifying whether billing tones are actually

present.

L3

TIP

Although the DAA will remain off-hook during a billing

tone event, the received data from the line will be

corrupted (or a modem disconnect or retrain may occur)

in the presence of large billing tones. If the user wishes

to receive data through a billing tone, an external LC

filter must be added. A modem manufacturer can

provide this filter to users in the form of a dongle that

connects on the phone line before the DAA. This keeps

the manufacturer from having to include a costly LC filter

internal to the modem when it may only be necessary to

support a few countries/customers.

L4

FROM

LINE

To

DAA

C3

RING

Figure 18. Billing Tone Filter

^‘Table 29. Component Values—Optional Billing

Tone Filters

Alternatively, when a billing tone is detected, the host

software may notify the user that a billing tone has

occurred. This notification can be used to prompt the

user to contact the telephone company and have the

billing tones disabled or to purchase an external LC filter.

Symbol

C1,C2

C3

Value

0.027 μF, 50 V, ±10%

0.01 μF, 250 V, ±10%

L3

3.3 mH, >120 mA, <10 Ω, ±10%

10 mH, >40 mA, <10 Ω, ±10%

Billing Tone Filter (Optional)

L4

In order to operate without degradation during billing

tones in Germany, Switzerland, and South Africa, an

external LC notch filter is required. (The Si3015 can

remain off-hook during a billing tone event, but modem

data will be lost [or a modem disconnect or retrain may

occur] in the presence of large billing tone signals.) The

notch filter design requires two notches, one at 12 KHz

and one at 16 KHz. Because these components are

fairly expensive and few countries supply billing tone

support, this filter is typically placed in an external

dongle or added as a population option for these

countries. Figure 18 shows an example billing tone filter.

Figure 19 shows the billing tone filter and the ringer

impedance network for the Czech Republic. Both of

these circuits may be combined into a single external

dongle.

C1

0.027 F, 50 V

C2

0.027 F, 50 V

L3

3.3 mH, 120 mA

TIP

L4

3.3 mH, 40 mA

To

Si3015

Chipset

From

Line

L3 must carry the entire loop current. The series

resistance of the inductors is important to achieve a

narrow and deep notch. This design has more than

25 dB of attenuation at both 12 KHz and 16 KHz.

C3

0.01 F, 250 V

RING

Figure 19. Dongle Applications Circuit

Rev. 1.3

81

Si2400

The Si2400 receives the loopback tone and should be

programmed to drive the tone to AOUT. This approach

requires loop current consistent with the equivalent

circuit shown in Figure 1.

The billing tone filter affects the ac termination and

return loss. The current complex ac termination will

pass worldwide return loss specifications both with and

without the billing tone filter by at least 3 dB. The ac

termination is optimized for frequency response and

hybrid cancellation, while having greater than 4 dB of

margin with or without the dongle for South Africa,

Australia, CTR21, German, and Swiss country-specific

specifications.

As an example, the following strings can be sent to the

Si2400 to set up the 2225 Hz answer tone as the

stimulus waveform.

1. ATE0SF1=18SF7=00SF0=01 to go off hook and to disable

transmit hybrid.

2. ATSE4=02M2SF4=03 to drive AOUT with the received

loopback tone from the line.

In-Circuit Testing

The Si2400’s advanced design provides the system

manufacturer with increased ability to determine system

functionality during production line test, as well as

support for end-user diagnostics.

3. ATSE8=00SE6=00SE5=0BSE8=01SE6=08SE5=FCSE8=0

0 to set the tone amplitude to –12 dBm.

4. ATSE8=02SE5=04SE6=02 to begin the 2225 Hz answer

tone.

The CLKOUT pin of the Si2400 can be used as an initial

indication that the Si2400 is functional. Upon power up

and the negation of the reset pin, the CLKOUT pin

oscillates at 9.8304 MHz, which is twice the input clock

frequency of 4.9152 MHz. Testing the frequency of

CLKOUT indicates that the Si2400 internal clock is

operational. To test communication with the Si2400

across the UART, the local echo may be used

immediately after the part has been properly reset.

With the above strings a number of points can be

probed to determine if the DAA is functioning properly.

Assuming a 30 mA loop current, the dc value of the TIP/

RING voltage should be in the neighborhood of 7.5 V.

The actual voltage is dependent on the chosen dc

Termination. Refer to Figures 14, 15, and 16.

The amplitude of the 2225 Hz tone on AOUT should be

around 500 mV peak-to-peak, corresponding to

amplitude consistent with a –12.9 dBm signal. The

digital filters introduce the 0.9 dBm attenuation. The

transmitted tone is set to a –12 dBm level so that when

the hybrid is disabled, an internal dc offset is realized.

The size of this dc offset is approximately half scale. To

guarantee no clipping under all conditions, a –12 dBm

maximum is recommended. If a slightly distorted signal

is acceptable on AOUT, a signal exceeding –12 dBm

may be implemented instead using the method shown

in step 3 above.

There are many methods to check to discover whether

the ISOCAP link between the Si2400 and Si3015 is

operational. These tests do not require any loop current

on the DAA. The first method is to check SF2[3] (FDT).

If it is set, the Si2400 and the Si3015 are

communicating. Another method is to read SF8[7:4]

(LRV) to verify the Si3015 is properly sending its version

number back to the Si2400. Finally, the voltage between

the Si3015 VREG pin and the IGND pin may be

measured and must exceed 3.6 V.

In order to complete the production test, it may be

necessary to simulate a ring signal. A sine wave pulse

of 500 ms with a 20 Hz frequency and an amplitude of

Once the clock, UART, and isolation link have been

proven to function, the production test can proceed to

verify operation of the discrete components mounted on

the board. In general, there are two approaches to

production line test. The first approach is to execute

complete modem connections through a commercially

available telephone line simulator. This approach is

simple to implement but incurs a relatively long per unit

test time. If per unit test time is an important

consideration, another approach is to use the internal

tone generator on the Si2400 to generate a tone at TIP/

RING. The Si3015 can be programmed to disable the

hybrid (clearing SF1[2] [HBE]), thereby allowing the

transmitted signal to be looped back through the receive

path.

35 V

is sufficient for the Si2400 to return an “R”

RMS

result code. Additional production tests may be

employed to check the DAA. For example, a 300 V dc

test between TIP and RING can be used to ensure that

the hookswitch transistors are operational and are not

leaking any significant amount of current. Also, a HIPOT

(High Potential such as 1500 V) test applied

longitudinally between TIP/RING and GND can be used

to ensure that the isolation barrier is not bridged

inadvertently.

82

Rev. 1.3

Si2400

Compliance Test Commands

The following are compliance test commands:

ATS07=4ODT;

ATSE8=05\r

ATSE5=xx\r

// go off hook

// place DSP in mode 5 (for QAM and DPSK)

// see notes below for setting xx

Writes to the ATSE5 register has the following effect when in DSP

Mode 5

bit 0 : transmit_ena set to 1 turns the transmitter on.

bit 2 : QAM/nDPSK

If 0, DPSK algorithm is chosen

If 1, QAM algorithm is chosen

bit 3 : orig/nans selects between originate mode and answer mode.

If 0, answer mode

If 1, originate mode

bit 4 : When set, enables 550 Hz guard tone

bit 5 : When set, enables 1800 Hz guard tone

ATSE6=00

ATSE6=FF

// sending unscrambled zeros

// sending scarmbled ones

Rev. 1.3

83

Si2400

APPENDIX B—TYPICAL MODEM APPLICATIONS EXAMPLES

Si2400 may echo the following:

t – tone dial detected

Introduction

, – dialing complete

r – ringback

b – busy tone

Appendix B outlines the steps required to configure the

Si2400 for modem operation under typical examples.

The ISOmodem has been designed to be both easy to

N – No carrier

use and flexible. The Si2400 has many features and

c – connect

modes, which add to the complexity of the device, but

are not required for a typical modem configuration. The

6. Next byte after “c” is modem data!

goal of this appendix is to help the user to quickly make

a modem connection and begin evaluation of the

Si2400 under various operational examples.

Example 4: Bell 103 in Australia with

Parallel Phone Detect

1. Power on reset

Example 1: V.22bis in FCC countries

1. Power on reset

2. Set Host UART to 2400 bps with CTS flow control

3. ATS07=01 (set for FSK 300 bps)

4. ATSF5=38 (set DAA for Australia)

5. ATSE2=C0 (enable ALERT pin)

2. Set Host UART to 2400 bps

3. ATS07=06 set for QAM 2400 bps

4. ATDT18005551212<CR>

Si2400 may echo the following:

t – tone dial detected

, – dialing complete

r – ringback

6. ATDT18005551212<CR>

Si2400 may echo the following:

t – tone dial detected

, – dialing complete

r – ringback

b – busy tone

N – No carrier

c – connect

d – connect at 1200bps

7. Next byte after “c” is modem data!

5. Next byte after “c” or “d” is modem data!

Example 5: Bell 212A in South Korea with

Japanese caller ID

Example 2: V.22 in CTR21 countries

1. Power on reset

2. Set Host UART to 2400 bps with CTS flow control

3. ATS07=02 (set for DPSK 1200 bps)

4. ATSF5=1C (set DAA for CTR21)

5. ATSF7=18 (set DAA for CTR21)

2. Set Host UART to 2400 bps with CTS flow control

3. ATS07=00 (set for DPSK 1200 bps)

4. ATSF5=06(set DAA for South Korea)

5. ATS13=80 (set caller ID to Japanese format)

When caller ID data is detected, Si2400 will echo “f”

indicating the line reversal, “m” indicating the mark, and

then caller ID data will follow.

6. ATDT18005551212<CR>

Si2400 may echo the following:

t – tone dial detected

, – dialing complete

r – ringback

6. ATDT18005551212<CR>

-Si2400 may echo:

t – tone dial detected

, – dialing complete

r – ringback

b – busy tone

N – No carrier

c – connect

7. Next byte after “c” is modem data!

b – busy tone

N – No carrier

c – connect

Example 3: Bell 103 in Australia

1. Power on reset

7. Next byte after “c” is modem data!

2. Set Host UART to 2400 bps with CTS flow control

3. ATS07=01 (set for FSK 300 bps)

4. ATSF5=38 (set DAA for Australia)

5. ATDT18005551212<CR>

84

Rev. 1.3

Si2400

APPENDIX C—UL1950 3RD EDITION

Designs using the Si2400 pass all overcurrent and on the protected side of the sidactor (RV1). For this

overvoltage tests for UL1950 3rd Edition compliance design, the ferrite beads can be rated at 200 mA.

with a couple of considerations.

In a cost-optimized design, it is important to remember

Figure 20 shows the designs that can pass the UL1950

overvoltage tests, as well as electromagnetic emissions.

The top schematic of Figure 20 shows the configuration

in which the ferrite beads (FB1, FB2) are on the

unprotected side of the sidactor (RV1). For this

configuration, the current rating of the ferrite beads

must be 6 A.

that compliance to UL1950 does not always require

overvoltage tests. It is best to plan ahead and know

which overvoltage tests will apply to your system.

System-level elements in the construction, such as fire

enclosure and spacing requirements, need to be

considered during the design stages. Consult with your

Professional Testing Agency during the design of the

product to determine which tests apply to your system.

The bottom schematic of Figure 20 shows the

configuration in which the ferrite beads (FB1, FB2) are

C24

75 Ω @ 100 MHz, 6A

1.25 A

FB1

TIP

Fuse/PTC

RV1

75 Ω @ 100 MHz, 6A

FB2

RING

C25

Note: In this configuration, C24 and C25 are used for

emissions testing.

1000 Ω @ 100 MHz, 200 mA

C24

1.25 A

FB1

TIP

Fuse/PTC

RV1

1000 Ω @ 100 MHz, 200 mA

FB2

RING

C25

Figure 20. Circuits that Pass all UL1950 Overvoltage Tests

Rev. 1.3

85

Si2400

9. Pin Descriptions: Si2400

1

2

3

4

5

6

7

8

XTALI

XTALO

GPIO1

GPIO2

GPIO3

ISOB

16

15

14

13

12

11

10

9

CLKOUT

V

D

RXD

TXD

GND

C1A

CTS

GPIO4

AOUT

RESET

Pin #

Pin Name

Description

1

XTALI

XTALI—Crystal Oscillator Pin.

These pins provide support for parallel resonant, AT cut crystals. XTALI also acts as

an input in the event that an external clock source is used in place of a crystal.

2

3

XTALO

XTALO—Crystal Oscillator Pin.

Serves as the output of the crystal amplifier. A 4.9152 MHz crystal is required or a

4.9152 MHz clock on XTALI.

CLKOUT

Clock Output.

This signal is typically used to clock an output system microcontroller. The frequency

is 78.6432 MHz/(N+1), where N is programmable from 0 to 31. N defaults to 7 on

power up. Setting N = 0 stops the clock.

4

5

6

7

VD

Digital Supply Voltage.

Provides the digital supply voltage to the Si2400. Nominally either 5 V or 3.3 V.

RXD

TXD

CTS

Receive Data.

Serial communication data from the Si2400.

Transmit Data.

Serial communication data to the Si2400.

Clear to Send.

Clear to send output used by the Si2400 to signal that the device is ready to receive

more digital data on the TXD pin.

8

9

RESET

AOUT

Reset Input.

An active low input that is used to reset all control registers to a defined, initialized

state. Also used to bring the Si2400 out of sleep mode.

Analog Speaker Output.

Provides an analog output signal for monitoring call progress tones or to output voice

data to a speaker.

86

Rev. 1.3

Si2400

Pin #

Pin Name

Description

10

GPIO4

General Purpose Input/Output 4.

This pin can be either a GPIO pin (analog in, digital in, digital out) or the ALERT pin.

Default is digital in. When programmed as ALERT, this pin provides five functions.

While the modem is connected, it will normally be low, but will go high if the carrier is

lost, a wake-on ring (using the “ATZ” command) event is detected, a loss of loop cur-

rent event is detected, V.23 reversal is detected, or if an intrusion event has been

detected. The ALERT pin is sticky, and will stay high until the host clears it by writing

to the correct S register. (See register SE2[7:6].)

11

12

13

14

C1A

GND

Isolation Capacitor 1A.

Connects to one side of the isolation capacitor C1.

Ground.

Connects to the system digital ground.

ISOB

GPIO3

Bias Voltage.

This pin should be connected via the C3 capacitor.

General Purpose Input/Output 3.

This pin can be either a GPIO pin (analog in, digital in, digital out) or the ESC pin.

Default is digital in. When programmed as ESC, a positive edge on this pin will cause

the modem to go from online (connected) mode to the offline (command) mode.

15

16

GPIO2

GPIO1

General Purpose Input/Output 2.

This pin can be either a GPIO pin (analog in, digital in, digital out) or the TXD2 pin.

Default is digital in. The user can program this pin to function as TXD2 if the second-

ary serial interface is enabled. This pin is also used as the active low carrier detect pin

(CD) if enabled via the CDE bit in (S0C.7).

General Purpose Input Output 1.

This pin can be either a GPIO pin (analog in, digital in, digital out) or the RXD2 pin.

Default is digital. The user can program this pin to function as RXD2 if the secondary

serial interface is enabled. This pin can also be programmed to function as the EOFR

(end of frame receive) signal for HDLC framing.

Rev. 1.3

87

Si2400

10. Pin Descriptions: Si3015

QE2

DCT

IGND

C1B

FILT2

FILT

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

RX

REXT

REXT2

REF

RNG1

RNG2

QB

VREG2

VREG

QE

Table 30. 3015 Pin Descriptions

Description

Pin #

Pin Name

1

QE2

Transistor Emitter 2.

Connects to the emitter of Q4.

2

3

4

5

DCT

IGND

C1B

DC Termination.

Provides dc termination to the telephone network

Isolated Ground.

Connects to ground on the line-side interface. Also connects to capacitor C2.

Isolation Capacitor 1B.

Connects to one side of isolation capacitor C1.

RNG1

Ring 1.

Connects through a capacitor to the TIP lead of the telephone line. Provides the ring

and caller ID signals to the Si2400.

6

RNG2

Ring 2.

Connects through a capacitor to the RING lead of the telephone line. Provides the ring

and caller ID signals to the Si2400.

7

8

QB

QE

Transistor Base.

Connects to the base of transistor Q3.

Transistor Emitter.

Connects to the emitter of Q3.

9

VREG

VREG2

REF

Voltage Regulator.

Connects to an external capacitor to provide bypassing for an internal power supply.

10

11

12

13

Voltage Regulator 2.

Connects to an external capacitor to provide bypassing for an internal power supply.

Reference.

Connects to an external resistor to provide a high accuracy reference current.

REXT2

REXT

External Resistor 2.

Sets the complex ac termination impedance.

External Resistor.

Sets the real ac termination impedance.

88

Rev. 1.3

Si2400

Table 30. 3015 Pin Descriptions (Continued)

Description

Pin #

Pin Name

14

RX

Receive Input.

Serves as the receive side input from the telephone network.

15

16

FILT

Filter.

Provides filtering for the dc termination circuits.

FILT2

Filter 2.

Provides filtering for the bias circuits.

Rev. 1.3

89

Si2400

11. Ordering Guide

Chipset

Si2400

Region

System-Side

Si2400-KS

Si2400-BS

Si2400-FS

Line-Side

Si3015-KS

Si3015-BS

Si3015-F-FS

Pb-Free

No

Temp. Range

0 to 70 °C

Global

No

–40 to 85 °C

0 to 70 °C

Yes

90

Rev. 1.3

Si2400

12. Package Outline: 16-Pin SOIC

Figure 21 illustrates the package details for the Si2400 and Si3015. Table 31 lists the values for the dimensions

shown in the illustration.

16

9

h

bbb B

E

H

-B-

θ

1

8

L

B

aaa C A B

Detail F

-A-

D

C

A

-C-

A1

e

See Detail F

γ

Approximate device weight is 152 mg.

Seating Plane

Figure 21. 16-pin Small Outline Integrated Circuit (SOIC) Package

Table 31. Package Diagram Dimensions

Millimeters

Symbol

Min

1.35

.10

Max

1.75

.25

A

A1

B

.33

.51

C

.19

.25

D

E

9.80

3.80

10.00

4.00

e

1.27 BSC

H

h

5.80

.25

6.20

.50

L

.40

1.27

γ

0.10

θ

0º

8º

aaa

bbb

0.25

Rev. 1.3

91

Si2400

DOCUMENT CHANGE LIST

Revision 1.1 to Revision 1.2

Table 3 on page 6, GPIO1–4 (V ) changed to

OL

20 mA.

Table 4 on page 6, GPIO1–4 (V ) changed to

OL

15 mA.

Table 5 on page 7, Caller ID Common Mode

Tolerance added.

Updated !7, !1 description of page 34.

Added "Compliance Test Commands" on page 83.

Register S33 (MDMO)., “Modem Override,” on page

57, bit 0 (TSAL) definition corrected.

Updated "11.Ordering Guide" on page 90.

SOIC outline updated.

Revision 1.2 to Revision 1.3

Updated "11.Ordering Guide" on page 90.

92

Rev. 1.3

Si2400

NOTES:

Rev. 1.3

93

Si2400

CONTACT INFORMATION

Silicon Laboratories Inc.

4635 Boston Lane

Austin, TX 78735

Tel: 1+(512) 416-8500

Fax: 1+(512) 416-9669

Toll Free: 1+(877) 444-3032

Email: ISOinfo@silabs.com

Internet: www.silabs.com

The information in this document is believed to be accurate in all respects at the time of publication but is subject to change without notice.

Silicon Laboratories assumes no responsibility for errors and omissions, and disclaims responsibility for any consequences resulting from

the use of information included herein. Additionally, Silicon Laboratories assumes no responsibility for the functioning of undescribed features

or parameters. Silicon Laboratories reserves the right to make changes without further notice. Silicon Laboratories makes no warranty, rep-

resentation or guarantee regarding the suitability of its products for any particular purpose, nor does Silicon Laboratories assume any liability

arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation conse-

quential or incidental damages. Silicon Laboratories products are not designed, intended, or authorized for use in applications intended to

support or sustain life, or for any other application in which the failure of the Silicon Laboratories product could create a situation where per-

sonal injury or death may occur. Should Buyer purchase or use Silicon Laboratories products for any such unintended or unauthorized ap-

plication, Buyer shall indemnify and hold Silicon Laboratories harmless against all claims and damages.

Silicon Laboratories, Silicon Labs, and ISOmodem are trademarks of Silicon Laboratories Inc.

Other products or brandnames mentioned herein are trademarks or registered trademarks of their respective holders

94

Rev. 1.3


型号：	SI2400-BS
厂家：	SILICON
描述：	Modem, 2.4kbps Data, PDSO16, SOIC-16 电信光电二极管电信集成电路
文件：	总94页 (文件大小：926K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

SI2400-BS [SILICON]

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