S-35392A [SII]
2-WIRE REAL-TIME CLOCK; 2线实时时钟
| 型号： | S-35392A |
| 厂家： | 
SEIKO INSTRUMENTS INC |
| 描述： | 2-WIRE REAL-TIME CLOCK |
| 文件： | 总47页 (文件大小：617K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Rev.1.3_00
2-WIRE REAL-TIME CLOCK
S-35392A
The S-35392A is a CMOS 2-wire real-time clock IC which operates with the very low current
consumption and in the wide range of operation voltage. The operation voltage is 1.3 V to 5.5
V so that this IC can be used for various power supplies from main supply to backup battery.
Due to the 0.45 µA current consumption and wide range of power supply voltage at time
keeping, this IC makes the battery life longer. In the system which operates with a backup
battery, the included free registers can be used as the function for user’s backup memory.
Users always can take back the information in the registers which is stored before power-off
the main power supply, after the voltage is restored.
This IC has the function to correct advance/delay of the clock data speed, in the wide range,
which is caused by the oscillation circuit’s frequency deviation. Correcting according to the
temperature change by combining this function and a temperature sensor, it is possible to
make a high precise clock function which is not affected by the ambient temperature.
Features
• Low current consumption :
0.45 µA typ. (VDD = 3.0 V, Ta = 25°C)
• Constant output of 32.768 kHz clock pulse (Nch open-drain output)
• Wide range of operating voltage :
• Built-in clock-correction function
• Built-in free user register
1.3 to 5.5 V
• 2-wire (I2C-bus) CPU interface
• Built-in alarm interrupter
• Built-in flag generator during detection of low power voltage or at power-on
• Auto calendar up to the year 2099, automatic leap year calculation function
• Built-in constant voltage circuit
• Built-in 32.768 kHz crystal oscillator (Cd built in, Cg external)
• Package : SNT-8A
• Lead-free product
Applications
•
•
•
•
•
•
•
•
•
Mobile game devices
Mobile AV devices
Digital still cameras
Digital video cameras
Electronic power meters
DVD recorders
TVs, VCRs
Mobile phones, PHS
Car navigation
Package
Drawing Code
Package Name
SNT-8A
Package
PH008-A
Tape
PH008-A
Reel
Land
PH008-A
PH008-A
Seiko Instruments Inc.
1
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Pin Configuration
SNT-8A
Top view
8
7
6
5
VDD
SDA
SCL
INT2
32KO
XOUT
XIN
1
2
3
4
VSS
Figure 1 Pin Configuration (S-35392A-I8T1G)
List of Pin
Table 1
Pin No.
1
Symbol
Description
Pin for constant output of
32.768 kHz
I/O
Configuration
Nch open-drain output
(no protective diode at VDD)
32KO
Output
2
3
4
XOUT
XIN
VSS
Connection pin for crystal
oscillator
GND pin
Output pin for interrupt signal
2
−
−
−
−
Nch open-drain output
(no protective diode at VDD)
CMOS input
(no protective diode at VDD)
Nch open-drain output
5
Output
INT2
SCL
6
Input pin for serial clock
Input
7
8
SDA
VDD
I/O pin for serial data
Bi-directional (no protective diode at VDD)
CMOS input
Pin for positive power supply
−
−
2
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Pin Function
•
SDA (I/O for serial data) pin
This pin is to data input/output for I2C-bus interface. This pin inputs/outputs data by synchronizing with a clock pulse
from the SCL pin. This pin has CMOS input and Nch open drain output. Generally in use, pull up this pin to the VDD
potential via a resistor, and connect it to any other device having open drain or open collector output with wired-OR
connection.
•
SCL (input for serial clock) pin
This pin is to input a clock pulse for I2C-bus interface. The SDA pin inputs/outputs data by synchronizing with the clock
pulse.
•
•
•
XIN, XOUT (crystal oscillator connect) pin
Connect a crystal oscillator between XIN and XOUT.
32KO (constant output of 32.768 kHz) pin
This is an output pin for 32.768 kHz. This pin constantly outputs a clock pulse after power-on.
(output for interrupt signal 2) pin
INT2
This pin outputs a signal of interrupt, or a clock pulse. By using the status register 2, users can select either of; alarm
interrupt, output of user-set frequency, per-minute edge interrupt or minute-periodical interrupt 1. This pin has Nch open
drain output.
•
•
VDD (positive power supply) pin
Connect this VDD pin with a positive power supply. Regarding the values of voltage to be applied, refer to “
Recommended Operation Conditions”.
VSS pin
Connect this VSS pin to GND.
Equivalent Circuits of I/O Pin
SCL
SDA
Figure 3 SCL Pin
Figure 2 SDA Pin
32KO, INT2
Figure 4 32KO Pin, INT2 Pin
Seiko Instruments Inc.
3
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Block Diagram
32KO
Divider,
timing generator
INT1
controller
XIN
Oscillator
INT1 register
XOUT
Comparator 1
Clock correction register
Real-time data register
Day Month Year
Status register 1
Status register 2
Day of
the week
Second Minute Hour
Comparator 2
Free register
INT2
INT2
controller
INT2 register
Shift register
Low power supply
voltage detector
VDD
VSS
Power-on
detector
SDA
SCL
Serial
interface
Constant-
voltage circuit
Figure 5
4
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Absolute Maximum Ratings
Table 2
Parameter
Power supply voltage
Input voltage
Symbol
VDD
VIN
VOUT
Topr
Tstg
Applicable Pin
Rating
Unit
V
V
V
°C
°C
−
V
V
V
SS − 0.3 to VSS + 6.5
SS − 0.3 to VSS + 6.5
SS − 0.3 to VSS + 6.5
−40 to +85
SCL, SDA
Output voltage
SDA, 32KO,
INT2
Operating ambient temperature*1
Storage temperature
−
−
−55 to +125
*1. Conditions with no condensation or frost. Condensation and frost cause short circuiting between pins, resulting in a
malfunction.
Caution The absolute maximum ratings are rated values exceeding which the product could suffer physical
damage. These values must therefore not be exceeded under any conditions.
Recommended Operation Conditions
Table 3
(VSS = 0 V)
Parameter
Symbol
VDD
Conditions
Ta = −40 to +85°C
Ta = −40 to +85°C
−
Min.
1.3
DET − 0.15
Typ.
3.0
−
Max.
5.5
5.5
7
Unit
V
V
Power supply voltage *1
Time keeping power supply voltage *2 VDDT
Crystal oscillator CL value
V
CL
−
6
pF
*1. The power supply voltage that allows communication under the conditions shown in Table 8 of “ AC Electrical
Characteristics”.
*2. The power supply voltage that allows time keeping. For the relationship with VDET (low power supply voltage detection
voltage), refer to “ Characteristics (Typical Data)”.
Oscillation Characteristics
Table 4
(Ta = 25°C, VDD = 3.0 V, VSS = 0 V, VT-200 crystal oscillator (CL = 6 pF, 32.768 kHz) manufactured by Seiko Instruments Inc.)
Parameter
Symbol
VSTA
tSTA
δIC
δV
Cg
Conditions
Within 10 seconds
−
Min.
1.1
−
−10
−3
−
Typ.
−
−
−
−
−
8
Max.
5.5
1
+10
+3
Unit
V
s
ppm
ppm/V
pF
Oscillation start voltage
Oscillation start time
IC-to-IC frequency deviation*1
Frequency voltage deviation
External capacitance
−
VDD = 1.3 to 5.5 V
Applied to XIN pin
Applied to XOUT pin
9.1
−
Internal oscillation capacitance
*1. Reference value
Cd
−
pF
Seiko Instruments Inc.
5
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
DC Electrical Characteristics
Table 5 DC Characteristics (VDD = 3.0 V)
(Ta = −40 to +85°C, VSS = 0 V, VT=200 crystal oscillator (CL = 6 pF, 32.768 kHz, Cg = 9.1 pF) manufactured by Seiko Instruments Inc.)
Parameter
Current consumption 1
Symbol
IDD1
Applicable Pin
Conditions
Min.
−
Typ.
0.45
Max.
1.13
Unit
µA
−
Out of communication
During communication
(SCL = 100 kHz)
VIN = VDD
Current consumption 2
IDD2
−
−
6
14
µA
Input current leakage 1
Input current leakage 2
Output current leakage 1 IOZH
IIZH
IIZL
SCL, SDA
SCL, SDA
−0.5
−0.5
−0.5
−0.5
0.8 × VDD
SS − 0.3
3
5
−
−
−
0.5
0.5
0.5
0.5
µA
µA
µA
µA
V
V
mA
mA
VIN = VSS
VOUT = VDD
VOUT = VSS
−
SDA, 32KO,
INT2
INT2
Output current leakage 2 IOZL
−
−
−
5
SDA, 32KO,
SCL, SDA
SCL, SDA
Input voltage 1
Input voltage 2
Output current 1
VIH
VIL
IOL1
IOL2
VSS + 5.5
0.2 × VDD
−
V
VOUT = 0.4 V
VOUT = 0.4 V
−
−
32KO,
SDA
INT2
Output current 2
10
Power supply voltage
detection voltage
VDET
−
−
0.65
1
1.35
V
Table 6 DC Characteristics (VDD = 5.0 V)
(Ta = −40 to +85°C, VSS = 0 V, VT-200 crystal oscillator (CL = 6 pF, 32.768 kHz, Cg = 9.1 pF) manufactured by Seiko Instruments Inc.)
Parameter
Current consumption 1
Symbol
IDD1
Applicable Pin
Conditions
Min.
−
Typ.
0.6
Max.
1.4
Unit
µA
−
Out of communication
During communication
(SCL = 100 kHz)
VIN = VDD
Current consumption 2
IDD2
−
−
14
30
µA
Input current leakage 1
Input current leakage 2
Output current leakage 1 IOZH
IIZH
IIZL
SCL, SDA
SCL, SDA
−0.5
−0.5
−0.5
−0.5
0.8 × VDD
SS − 0.3
5
6
−
−
−
0.5
0.5
0.5
0.5
µA
µA
µA
µA
V
V
mA
mA
VIN = VSS
VOUT = VDD
VOUT = VSS
−
SDA, 32KO,
INT2
INT2
Output current leakage 2 IOZL
−
−
−
8
SDA, 32KO,
SCL, SDA
SCL, SDA
Input voltage 1
Input voltage 2
Output current 1
VIH
VIL
IOL1
IOL2
VSS + 5.5
0.2 × VDD
−
V
VOUT = 0.4 V
VOUT = 0.4 V
−
−
32KO,
SDA
INT2
Output current 2
13
Power supply voltage
detection voltage
VDET
−
−
0.65
1
1.35
V
6
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
AC Electrical Characteristics
VDD
Table 7 Measurement Conditions
Input pulse voltage
Input pulse rise/fall time
VIH = 0.9 × VDD, VIL = 0.1 × VDD
20 ns
R = 1 kΩ
Output determination voltage VOH = 0.5 × VDD, VOL = 0.5 × VDD
Output load 100 pF + pull-up resistor 1 kΩ
SDA
C = 100 pF
Remark The power supplies of the IC
and load have the same
electrical potential.
Figure 6 Output Load Circuit
Table 8 AC Electrical Characteristics
(Ta = −40 to +85°C)
VDD *2 ≥ 1.3 V
VDD *2 ≥ 3.0 V
Parameter
Symbol
Unit
Min.
0
4.7
4
Typ.
−
−
−
−
Max.
100
−
Min.
0
Typ.
−
Max.
400
−
−
0.9
−
SCL clock frequency
SCL clock low time
fSCL
kHz
µs
µs
µs
µs
µs
ns
tLOW
tHIGH
tPD
1.3
0.6
−
−
SCL clock high time
SDA output delay time*1
Start condition setup time
Start condition hold time
Data input setup time
Data input hold time
Stop condition setup time
SCL, SDA rise time
SCL, SDA fall time
−
3.5
−
−
−
−
−
1
0.3
−
−
−
−
tSU.STA
tHD.STA
tSU.DAT
tHD.DAT
tSU.STO
tR
4.7
4
250
0
4.7
−
−
−
−
−
−
−
−
0.6
0.6
100
0
−
−
−
−
−
−
−
−
0.3
0.3
−
µs
µs
µs
µs
µs
ns
0.6
−
−
1.3
−
−
−
−
−
tF
−
Bus release time
Noise suppression time
tBUF
tI
4.7
−
−
−
100
−
50
*1. Since the output format of the SDA pin is Nch open-drain output, SDA output delay time is determined by the values of
the load resistance (RL) and load capacity (CL) outside the IC. Therefore, use this value only as a reference value.
*2. Regarding the power supply voltage, refer to “ Recommended Operation Conditions”.
tR
tF
tHIGH
tLOW
SCL
tSU.STO
tHD.DAT
tSU.DAT
tHD.STA
tSU.STA
SDA
(Input from
S-35392A)
tBUF
tPD
SDA
(Output from
S-35392A)
Figure 7 Bus Timing
Seiko Instruments Inc.
7
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Configuration of Data Communication
1. Configuration of data communication
For data communication, the master device in the system generates a start condition for the S-35392A. Next, the master
device transmits 4-bit device code “0110”, 3-bit command and 1-bit Read/Write command to the SDA bus. After that,
output or input is performed from B7 of data. If data I/O has been completed, finish communication by inputting a stop
condition to the S-35392A. The master device generates an acknowledgment signal for every 1-byte. Regarding details,
refer to “ Serial Interface”.
Read/Write bit
Start condition
Acknowledgment bit
Device code
Command
C1
STA
0
1
1
0
C2
C0
R / W ACK
Stop condition
1-byte data
B7
B6
B5
B4
B3
B2
B1
B0
ACK
STP
Figure 8 Data Communication
8
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
2. Configuration of command
8 types of command are available for the S-35392A, The S-35392A does Read/Write the various registers by inputting
these fixed codes and commands. The S-35392A does not perform any operation with any codes and commands other
than those below.
Table 9 List of Command
Device
Code
Command
Description
Data
C2 C1 C0
B7
B6
B5
B4
B3
B2
B1
B0
0
0
0
0
0
1
Status register 1 access
Status register 2 access
RESET*1 12/24 SC0*2 SC1*2 INT1*3 INT2*3 BLD*4 POC*4
INT1FE INT1ME INT1AE SC2*2 INT2FE INT2ME INT2AE TEST*5
Y1
M1
D1
W1
H1
m1
s1
H1
m1
s1
Y2
M2
D2
W2
H2
m2
s2
H2
m2
s2
Y4
M4
D4
W4
H4
m4
s4
H4
m4
s4
Y8
M8
D8
Y10
M10
D10
Y20
−
Y40
Y80
*6
*6
*6
−
−
*6
*6
D20
−
−
Real-time data 1 access
(year data to)
*6
*6
*6
*6
*6
0
0
1
1
1
0
0
1
0
−
−
−
−
−
*6
H8
m8
s8
H8
m8
s8
H10
m10
s10
H10
m10
s10
H20 AM/PM
m20
s20
H20 AM/PM
m20
s20
−
*6
m40
s40
−
*6
−
*6
−
Real-time data 2 access
(hour data to)
*6
m40
s40
−
*6
−
INT1 register access
(alarm time 1: week/hour/minute)
(INT1AE = 1, INT1ME = 0,
INT1FE = 0)
*6
*6
*6
*6
W1
H1
m1
W2
H2
m2
W4
H4
m4
−
−
−
−
A1WE
0110
H8
m8
H10
m10
H20 AM/PM A1HE
m20 m40 A1mE
INT1 register access
(free register)
SC3*2 SC4*2 SC5*2 SC6*2 SC7*2 SC8*2 SC9*2 SC10*2
(settings other than alarm time 1)
INT2 register access
(alarm time 2: week/hour/minute)
(INT2AE = 1, INT2ME = 0,
INT2FE = 0)
*6
*6
*6
*6
W1
H1
m1
W2
H2
m2
W4
H4
m4
−
−
−
−
A2WE
H20 AM/PM A2HE
m20 m40 A2mE
H8
m8
H10
m10
1
0
1
INT2 register access
(
output of user-set frequency
)
1 Hz
2 Hz
4 Hz
8 Hz
16 Hz SC11*2 SC12*2 SC13*2
(INT2ME = 0, INT2FE = 1)
Clock correction register access
Free register access
1
1
1
1
0
1
V0
F0
V1
F1
V2
F2
V3
F3
V4
F4
V5
F5
V6
F6
V7
F7
*1. Write-only flag. The S-35392A initializes by writing “1” in this register.
*2. Scratch bit. A R/W-enabled, user-free register.
*3. Read-only flag. Valid only when using the alarm function. When the alarm time matches, this flag is set to “1”, and it is
cleared to “0” when Read.
*4. Read-only flag. “POC” is set to “1” when power is applied. It is cleared to “0” when Read. Regarding “BLD”, refer to “
Low Power Supply Voltage Detection Circuit”.
*5. Test bit for SII. Be sure to set “0” in use.
*6. No effect by Write. It is “0” when Read.
Seiko Instruments Inc.
9
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Configuration of Register
1. Real-time data register
The real-time data register is a 7-byte register that stores the data of year, month, day, day of the week, hour, minute, and
second in the BCD code. To Write/Read real-time data 1 access, transmit/receive the data of year in B7, month, day, day
of the week, hour, minute, second in B0, in 7-byte. When you skip the procedure to access the data of year, month, day,
day of the week, Read/Write real-time data 2 access. In this case, transmit/receive the data of hour in B7, minute, second
in B0, in 3-byte.
Year data (00 to 99)
Start bit of real-time data 1 data access
Y1
B7
Y2
Y40
Y4
Y8
Y10 Y20
Y80
B0
Month data (01 to 12)
M1
B7
M2
M4
M8 M10
0
0
0
B0
Day data (01 to 31)
D1
B7
D2
D4
D8
D10 D20
0
0
0
B0
Day of the week data (00 to 06)
W1
B7
W2
W4
0
0
0
0
B0
Hour data (00 to 23 or 00 to 11)
Start bit of real-time data 2 data access
H2
H1
B7
H4
H8
H10 H20
0
AM / PM
B0
Minute data (00 to 59)
m1
B7
m2
m4
m8
m10 m20 m40
0
B0
Second data (00 to 59)
s1
s2
s4
s8
s10 s20
s40
0
B7
B0
Figure 9 Real-Time Data Register
10
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Year data (00 to 99): Y1, Y2, Y4, Y8, Y10, Y20, Y40, Y80
Sets the lower two digits of the Western calendar year (00 to 99) and links together with the auto calendar
function until 2099.
Example: 2053 (Y1, Y2, Y4, Y8, Y10, Y20, Y40, Y80) = (1, 1, 0, 0, 1, 0, 1, 0)
Month data (01 to 12): M1, M2, M4, M8, M10
Example: December (M1, M2, M4, M8, M10, 0, 0, 0) = (0, 1, 0, 0, 1, 0 ,0 ,0)
Day data (01 to 31): D1, D2, D4, D8, D10, D20
The count value is automatically changed by the auto calendar function.
1 to 31: Jan., Mar., May, July, Aug., Oct., Dec., 1 to 30: April, June, Sep., Nov.
1 to 29: Feb. (leap year), 1 to 28: Feb. (non-leap year)
Example: 29 (D1, D2, D4, D8, D10, D20, 0, 0) = (1, 0, 0, 1, 0, 1, 0, 0)
Day of the week data (00 to 06): W1, W2, W4
A septenary up counter. Day of the week is counted in the order of 00, 01, 02, …, 06, and 00. Set up day of the
week and the count value.
Hour data (00 to 23 or 00 to 11): H1, H2, H4, H8, H10, H20, AM / PM
In a 12-hour expression, write 0; AM, 1; PM in the AM/PM bit. In a 24-hour expression, users can Write either
0 or 1. 0 is read when the hour data is from 00 to 11, and 1 is read when from 12 to 23.
Example (12-hour expression): 12 p.m. (H1, H2, H4, H8, H10, H20, AM/PM, 0) = (0, 1, 0, 0, 1, 0, 1, 0)
Example (24-hour expression): 22
(H1, H2, H4, H8, H10, H20, AM/PM, 0) = (0, 1, 0, 0, 0, 1, 1, 0)
Minute data (00 to 59): m1, m2, m4, m8, m10, m20, m40
Example: 32 minutes (m1, m2, m4, m8, m10, m20, m40, 0) = (0, 1, 0, 0, 1, 1, 0, 0)
Example: 55 minutes (m1, m2, m4, m8, m10, m20, m40, 0) = (1, 0, 1, 0, 1, 0, 1, 0)
Second data (00 to 59): s1, s2, s4, s8, s10, s20, s40
Example: 19 seconds (s1, s2, s4, s8, s10, s20, s40, 0) = (1, 0, 0, 1, 1, 0, 0, 0)
Seiko Instruments Inc.
11
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
2. Status register 1
Status register 1 is a 1-byte register that is used to display and set various modes. The bit configuration is shown below.
B6
B5
B4
B3
B2
B1
B0
B7
RESET
W
12 / 24
R/W
SC0
R/W
SC1
R/W
INT1
R
INT2
R
BLD
R
POC
R
R:
Read
Write
Read/Write
W:
R/W:
Figure 10 Status Register 1
B0 : POC
This flag is used to confirm whether the power is on. The power-on detector operates at power-on and B0 is set to “1”.
This flag is Read-only. Once it is read, it is automatically set to “0”. When this flag is “1”, be sure to initialize. Regarding
the operation after power-on, refer to “ Power-on Detection Circuit and Register Status”.
B1 : BLD
This flag is set to “1” when the power supply voltage decreases to the level of detection voltage (VDET) or less. Users
can detect a drop in the power supply voltage. This flag is set to “1” once, is not set to “0” again even if the power
supply increases to the level of detection voltage (VDET) or more. This flag is Read-only. When this flag is “1”, be sure
to initialize. Regarding the operation of the power supply voltage detection circuit, refer to “ Low Power Supply
Detection Circuit”.
B2 : INT2, B3 : INT1
This flag indicates the time set by alarm and when the time has reached it. This flag is set to “1” when the time that
users set by using the alarm function has come. The INT1 flag in “1” in the alarm 1 function mode, the INT2 flag in “1”
in the alarm 2 interrupt mode. This flag is Read-only. This flag is read once, is set to “0” automatically.
B4 : SC1, B5 : SC0
These flags are SRAM type registers, they are 2 bits as a whole, can be freely set by users.
B6 : 12 / 24
This flag is used to set 12-hour or 24-hour expression.
0 : 12-hour expression
1 : 24-hour expression
B7 : RESET
The internal IC is initialized by setting this bit to “1”. This bit is Write-only. It is always “0” when Read. When applying
the power supply voltage to the IC, be sure to write “1” to this bit to initialize the circuit. Regarding each status of data
after initialization, refer to “ Register Status After Initialization”.
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Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
3. Status register 2
Status register 2 is a 1-byte register that is used to display and set various modes. The bit configuration is shown below.
B6
B5
B4
B3
B2
B1
B0
B7
INT2FE
R/W
INT2ME
R/W
INT2AE
R/W
TEST
R/W
INT1FE
R/W
INT1AE
R/W
SC2
R/W
INT1ME
R/W
R/W: Read/Write
Figure 11 Status Register 2
B0 : TEST
This is a test flag for SII. Be sure to set this flag to “0” in use. If this flag is set to “1”, be sure to initialize to set “0”.
B1 : INT2AE, B2 : INT2ME, B3 : INT2FE
These bits are used to select the output mode for the
pin. Table 10 shows how to select the mode. To use
INT2
alarm 2 interrupt, access the INT2 register after setting the alarm interrupt mode.
Table 10 Output Modes for INT2 Pin
INT2AE
0
INT2ME
INT2FE
INT2 Pin Output Mode
0
0
1
1
0
0
1
0
1
0
No interrupt
*1
−
Output of user-set frequency
Per-minute edge interrupt
Minute-periodical interrupt 1 (50% duty)
Alarm 2 interrupt
*1
−
*1
−
1
*1. Don’t care (Both of 0 and 1 are acceptable).
B4 : SC2
This is an SRAM type register that can be freely set by users.
B5 : INT1AE, B6 : INT1ME, B7 : INT1FE
To use the alarm 1 function, access the INT register 1 after setting INT1AE = “1”, INT1ME = “0”, and INT1FE = “0”.
In other settings than this, these flags are disable for setting the alarm time (free registers).
Seiko Instruments Inc.
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2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
4. INT1 register and INT2 register
The INT1 register is to set up the alarm time. The INT2 register is to set up the output of user-set frequency or alarm
interrupt. To switch the output mode, use the status register 2.
The INT1 register works as an alarm-time data register in the alarm 1 interrupt mode selected by users. The INT1 flag (B3
in the status register) displays the alarm time when it matches.
The INT2 register works as an alarm-time data register in the alarm interrupt mode selected by using the status register 2.
In the mode output of user-set frequency, the INT2 register works as a data register to set up the frequency for output
clock. Clock pulse and output of alarm interrupt are output from the
register) displays the alarm time when it matches.
pin. And The INT2 flag (B2 in the status
INT2
(1) Alarm interrupt
Users can set the alarm time (the data of day of the week, hour, minute) by using the INT1 and INT2 registers which
are 3-byte data registers. The configuration of register is as well as the data register of day of the week, hour, minute,
in the real-time data register; is expressed by the BCD code. Do not set a nonexistent day. Users are necessary to set
up the alarm-time data according to the 12/24 hour expression that they set by using the status register 1.
INT1 register
W1 W2
INT2 register
W1
A1WE
W4
0
0
W2
W4
0
0
0
A2WE
0
0
0
B7
B0
B7
B0
AM /
PM
AM /
PM
H2 H4 H8
A1HE
A2HE
H1
B7
H20
H20
H10
H1 H2 H4 H8 H10
B7
B0
B0
m1
B7
m8 m10 m20 m40 A1mE
B0
m2
m4
m1
B7
m20 m40
A2mE
m8 m10
m2 m4
B0
Figure 12 INT1 Register and INT2 Register (Alarm-Time Data)
The INT1 register has A1WE, A1HE, A1mE at B0 in each byte. It is possible to make data valid; the data of day of the
week, hour, minute which are in the corresponded byte; by setting these bits to “1”. This is as well in A2WE, A2HE,
A2mE in the INT2 register.
Setting example: alarm time “7:00 pm” in the INT1 register
(a) 12-hour expression (status register 1 B6 = 0)
set up 7:00 PM
Data written to INT1 register
*1
*1
*1
*1
*1
*1
*1
Day of the week
Hour
−
−
−
−
−
−
−
0
1
1
1
1
0
0
0
1
Minute
0
B7
0
0
0
0
0
0
1
B0
*1. Don’t care (Both of 0 and 1 are acceptable).
(b) 24-hour expression (status register 1 B6 = 1)
set up 19:00 PM
Data written to INT1 register
*1
*1
*1
*1
*1
*1
*1
Day of the week
Hour
−
1
−
0
−
−
−
−
−
0
1
1
0
0
1
0
1
0
0
0
1*2
0
Minute
0
0
B7
B0
*1. Don’t care (Both of 0 and 1 are acceptable).
AM/ PM
*2. Set up the
flag along with the time setting.
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Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
(2) Free register (INT1 register)
The INT1 register is a 1-byte SRAM type register that can be set freely by users.
B6
B5
B4
B3
SC7
R/W
B2
B1
B0
B7
SC3
R/W
SC8
R/W
SC9
R/W
SC10
R/W
SC4
R/W
SC5
R/W
SC6
R/W
R/W: Read/Write
Figure 13 INT1 Register (Free Register)
(3) Output of user-set frequency (INT2 register)
The INT2 register is a 1-byte data register to set up the output frequency. Setting each bit B7 to B3 in the register to
“1”, the frequency which corresponds to the bit is output in the AND-form. SC11 to SC13 in the INT2 register are 3-bit
SRAM type registers that can be freely set by users.
B6
B5
B4
B3
B2
B1
B0
B7
1 Hz
R/W
16 Hz
R/W
SC11
R/W
SC12
R/W
SC13
R/W
2 Hz
R/W
4 Hz
R/W
8 Hz
R/W
R/W: Read/Write
Figure 14 INT2 Register (Data Register for Output Frequency)
Example: B7 to B3 = 50h
16 Hz
8 Hz
4 Hz
2 Hz
1 Hz
INT2 pin output
Status register 2
Set to INT2FE = 1
•
Figure 15 Example of Output from INT2 Register (Data Register for Output Frequency)
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2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
5. Clock-correction register
The clock-correction register is a 1-byte register that is used to correct advance/delay of the clock. When not using this
function, set this register to “00h”. Regarding the register values, refer to “ Function to Clock-Correction”.
B6
B5
B4
B3
B2
B1
B0
B7
V4
V5
V6
V7
V0
V1
V2
V3
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W: Read/Write
Figure 16 Clock-Correction Register
6. Free register
The free register is a 1-byte SRAM type register that can be set freely by users.
B6
B5
B4
B3
B2
B1
B0
B7
F4
F5
F6
F7
F0
F1
F2
F3
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W: Read/Write
Figure 17 Free Register
16
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Power-on Detector and Register Status
The power-on detection circuit operates by power-on the S-35392A, as a result each register is cleared; each register is set
as follows.
Real-time data register :
Status register 1 :
Status register 2 :
INT1 register :
00 (Y), 01 (M), 01 (D), 0 (day of the week), 00 (H), 00 (M), 00 (S)
“01h”
“01h”
“80h”
“00h”
“00h”
“00h”
INT2 register :
Clock correction register :
Free register :
“1” is set in the POC flag (B0 in the status register 1) to indicate that power has been applied. In this case, be sure to
initialize. The POC flag is set to “0” due to initialization. (Refer to “ Register Status After Initialization”.)
For the regular operation of power-on detection circuit, as seen in Figure 18, the period to power-up the S-35392A is that
the voltage reaches 1.3 V within 10 ms after setting the IC’s power supply voltage at 0 V. When the POC flag (B0 in the
status register) is not in “1”, in this case, power-on the S-35392A once again.
Do not transmit data immediately after power-on at least 0.5 sec because the power-on detection circuit is operating.
Within 10 ms
1.3 V
0 V*1
*1. 0 V indicates that there are no potential differences between the VDD
pin and VSS pin of the S-35392A.
Figure 18 How to Raise the Power Supply Voltage
Seiko Instruments Inc.
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2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Register Status After Initialization
The status of each register after initialization is as follows.
Real-time data register :
Status register 1 :
00 (Y), 01 (M), 01 (D), 0 (day of the week), 00 (H), 00 (M), 00 (S)
“0 B6 B5 B4 0 0 0 0 b”
(In B6, B5, B4, the data of B6, B5, B6 in the status register 1 at initialization is set.
Refer to Figure 19.)
“00h”
“00h”
“00h”
“00h”
“00h”
Status register 2 :
INT1 register :
INT2 register :
Clock correction register :
Free register :
Read from status register 1
9
Write to status register 1
18
0
1
9
18
0
1
SCL
SDA
R / W
R / W
1
0 0 0 0
0 1 1 0 0 0 0 0
1
0
L L L L
L
H
0
0 1 1 0 0 0 0
1
L L
Device code + command
Device code + command
B7 B5 : Not reset
B5
B7
Write “1” to reset flag and SC0.
: Output from S-35392A
: Input from master device
Figure 19 Status Register 1 Data at Initialization
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Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Low Power Supply Voltage Detection Circuit
The S-35392A has a low power supply voltage detection circuit, so that users can monitor drops in the power supply
voltage by reading the BLD flag (B1 in the status register 1). There is a hysteresis width of approx. 0.15 V (Typ.) between
detection voltage and release voltage (refer to “ Characteristics (Typical Data)”). The low power supply voltage
detection circuit does the sampling operation only once in one sec for 15.6 ms.
If the power supply voltage decreases to the level of detection voltage (VDET) or less, “1” is set to the BLD flag so that
sampling operation stops. Once “1” is detected in the BLD flag, no sampling operation is performed even if the power
supply voltage increases to the level of release voltage or more, and “1” is held in the BLD flag. After initialization, or once
the BLD flag is read, the BLD flag is automatically set to “0” to restart the sampling operation.
If the BLD flag is “1” even after the power supply voltage is recovered, be sure to initialize the circuit. Without initializing,
Read in the next BLD flag is done after sampling, the BLD flag gets reset to “0”. In this case, be sure to initialize although
the BLD flag is in “0” because the internal circuit may be in the indefinite status.
VDD
Hysteresis width
0.15 V approximately
Release voltage
Detection voltage
BLD flag
reading
1 s
1 s
Stop
Stop
Stop
15.6 ms
Sampling pulse
BLD flag
Figure 20 Timing of Low Power Supply Voltage Detection Circuit
Circuits Power-on and Low Power Supply Voltage Detection
Figure 21 shows the changes of the POC flag and BLD flag due to VDD fluctuation.
Low power supply
voltage detection
voltage
Low power supply
voltage detection
voltage
VDD
VSS
POC flag
BLD flag
Status register 1
reading
Figure 21 POC Flag and BLD Flag
Seiko Instruments Inc.
19
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Correction of Nonexistent Data and End-of-Month
When users write the real-time data, the S-35392A checks it. In case that the data is invalid, the S-35392A does the
following procedures.
1. Processing of nonexistent data
Table 11 Processing of Nonexistent Data
Register
Year data
Month data
Day data
Day of the week data
Normal Data
00 to 99
01 to 12
01 to 31
0 to 6
Nonexistent Data
XA to XF, AX to FX
00, 13 to 19, XA to XF
00, 32 to 39, XA to XF
7
Result
00
01
01
0
24-hour
12-hour
0 to 23
0 to 11
00 to 59
00 to 59
24 to 29, 3X, XA to XF
12 to 19, 2X, 3X, XA to XF
60 to 79, XA to XF
60 to 79, XA to XF
00
00
00
00
Hour data *1
Minute data
Second data *2
*1. In a 12-hour expression, Write the AM/PM flag (B1 in hour data in the real-time data register).
In 24-hour expression, the AM/PM flag in the real-time data register is omitted. However in the flag in Read, users are
able to read 0; 0 to 11, 1; 12 to 23.
*2. Processing of nonexistent data, regarding second data, is done by a carry pulse which is generated one sec after, after
Write. At this point the carry pulse is sent to the minute-counter.
2. Correction of end-of-month
A nonexistent day, such as February 30 and April 31, is set to the first day of the next month.
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Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
INT2
Alarm 1 Function and
Pin Output Mode
In the output mode for
pin, users are able to select the output;
INT2
alarm 2 interrupt, user-set frequency, per-minute edge interrupt, minute-periodical interrupt. To switch the output mode for
pin and the alarm 1 function, use the status register 2. Refer to 3. Status register 2 in “ Configuration of
INT2
Register”.
When switching the output mode for
pin, be careful of the output status of the pin. Especially, when using alarm 2
INT2
interrupt output, or the output of user-set frequency, switch the output mode after setting “00h” in the INT2 register. In
per-minute edge interrupt output/minute-periodical interrupt output, it is unnecessary to set data in the INT2 register for
users.
Refer to the followings regarding each operation of output modes.
1. Alarm 1 function and alarm 2 interrupt
Alarm 2 interrupt output is the function to set the INT2 flag “H” by the output “L” from the INT2 pin, at the alarm time
which is set by user has come. If setting the pin output to “H”, turn off the alarm function by setting “0” in INT2AE in the
status register 2.
By Read, the INT2 flag is once cleared automatically. In the alarm 1 function, the INT1 flag (B3 in the status register1) is
set to “H” when the set time has come. The INT1 flag is also cleared once by Read.
In the alarm 1 function, set the data of day of the week, hour, minute of the alarm time in the INT1 register. In alarm 2
interrupt, set in the INT2 register. Refer to “4. INT1 register and INT2 register” in “ Configuration of Register”.
Alarm setting of “W (day of the week), H (hour), m (minute)”
INTx register alarm enable flag
• AxHE = AxmE = AxWE = "1"
Status register 2 setting
• Alarm 1 function
INT1ME = INT1FE = 0
• Alarm 2 interrupt
INT1 register
INT2 register
INT2ME = INT2FE = 0
mx
Hx
Wx
Alarm 1 output
(B3 in status register 1)
Comparator
Alarm 2 interrupt (INT2 pin)/
alarm 2 output
(B2 in status register 1)
Day of
the week
Second Minute Hour
Real-time data
Day Month Year
W (day of the week)
59 s
H h 00 m 00 s
Change by program
01 s
H h (m − 1) m 59 s
H h (m + 1) m 00 s
Real-time data
Change by program
Change by program
INT1AE/INT2AE
Status register 1 reading
Alarm time matches
Alarm time matches
INT1 flag/
INT2 flag
*1
OFF
Period when alarm time matches
INT2 pin
*1. If users clear INT2AE once; “L” is not output from the INT2 pin by setting INT2AE enable again, within a period when
the alarm time matches real-time data.
Figure 22 Alarm Interrupt Output Timing (1/2)
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2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Alarm setting of “H (hour)”
Status register 2 setting
• Alarm 1 function
INT1ME = INT1FE = 0
• Alarm 2 interrupt
INT2ME = INT2FE = 0
INTx register alarm enable flag
• AxmE = AxWE = "0", AxHE = "1"
INT1 register
INT2 register
mx
Hx
Wx
Dx
Mx
Yx
Alarm 1 output
(B3 in status register 1)
Comparator
Alarm 2 interrupt (INT2 pin)/
alarm 2 output
(B2 in status register 1)
Day of
Day
Second
Month
59 s
Minute Hour
Year
the week
Real-time data
Real-time data
H h 00 m 00 s 01 s
Change by program
H h 01 m 00 s
H h 59 m 59 s (H + 1) h 00 m 00 s
(H − 1) h 59 m 59 s
Change by program
Change by program
Change by program
INT1AE/INT2AE
Status register 1 reading
Status register 1 reading
Alarm time matches
Alarm time matches
INT1 flag/
INT2 flag
*1
Alarm time
matches*2
*1
OFF
OFF
INT2 pin
Period when alarm time matches
*1. If users clear INT2AE once; “L” is not output from the INT2 pin by setting INT2AE enable again, within a period when
the alarm time matches real-time data.
*2. If turning the alarm output on by changing the program, within the period when the alarm time matches real-time data,
“L” is output again from the INT2 pin when the minute is counted up.
Figure 23 Alarm Interrupt Output Timing (2/2)
2. Output of user-set frequency
The output of user-set frequency is the function to output the frequency which is selected by using data, from the INT2
pin, in the AND-form. Set up the data of frequency in the INT2 register.
Refer to “4. INT1 register and INT2 register” in “ Configuration of Register”
Status register 2 setting
• INT2 pin output mode
Change by program
INT2AE = Don’t care (0 or 1), INT2ME = 0
INT2FE
Free-run output starts
OFF
INT2 pin
Figure 24 Output Timing of User-set Frequency
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Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
3. Per-minute edge interrupt output
Per-minute edge interrupt output is the function to output “L” from the
done, after selecting the output mode.
pin, when the first minute-carry processing is
INT2
To set the pin output to “H”, in the
this mode.
pin output mode, input “0” in INT2ME in the status register 2 in order to turn off
INT2
Status register 2 setting
• INT2 pin output mode
INT2AE = Don’t care (0 or 1), INT2FE = 0
Change by program
INT2ME
Minute-carry
processing
Minute-carry processing
OFF
INT2 pin
"L" is output again if this period is within 7.9 ms*1.
*1. Pin output is set to “H” by disabling the output mode within 7.9 ms, because the signal of this procedure is maintained
for 7.9 ms. Note that pin output is set to “L” by setting enable the output mode again.
Figure 25 Timing of Per-Minute Edge Interrupt Output
4. Minute-periodical interrupt output 1
The minute-periodical interrupt 1 is the function to output the one-minute clock pulse (Duty 50%) from the
when the first minute-carry processing is done, after selecting the output mode.
pin,
INT2
Status register 2 setting
• INT2 pin output mode
Change by program (OFF)
INT2AE = 0
INT2ME, INT2FE
Minute-carry
processing
Minute-carry
processing
Minute-carry
processing
Minute-carry
processing
Minute-carry
processing
INT2 pin
30 s
30 s
30 s
30 s
30 s
30 s
30 s
30 s
30 s
"L" is output again if this period is within 7.9 ms*1.
"H" is output again if this period is within 7.9 ms
"L" is output at the next minute-carry processing
*1. Setting the output mode disable makes the pin output “H”, while the output from the
pin is in “L”.
INT2
Note that pin output is set to “L” by setting enable the output mode again.
Figure 26 Timing of Minute-periodical Interrupt Output 1
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2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Function to Clock-Correction
The function to clock-correction is to correct advance/delay of the clock due to the deviation of oscillation frequency, in
order to make a high precise clock. For correction, the S-35392A adjusts the clock pulse by using a certain part of the
dividing circuit, not adjusting the frequency of the crystal oscillator. Correction is performed once every 20 seconds (or 60
seconds). The minimum resolution is approx. 3 ppm (or approx. 1 ppm) and the S-35392A corrects in the range of −195.3 to
+192.2 ppm (or of −65.1 to +64.1 ppm). (Refer to Table 12.) Users can set up this function by using the clock-correction
register. Regarding how to calculate the setting data, refer to “1. How to calculate”. When not using this function, be sure
to set “00h”.
Table 12 Function to Clock-Correction
B0 = 0
B0 = 1
Correction
Minimum resolution
Correction range
Every 20 seconds
3.052 ppm
−195.3 to +192.2 ppm
Every 60 seconds
1.017 ppm
−65.1 to +64.1 ppm
24
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
1. How to calculate
(1) If current oscillation frequency > target frequency (in case the clock is fast)
(Current oscillation frequency
(Target oscillation frequency*3)
actual measurement value*2)
−
Correction value*1 = 128 − Integral value
(Current oscillation frequency
(Minimum resolution*4)
×
actual measurement value*2)
Caution The figure range which can be corrected is that the calculated value is from 0 to 64.
*1. Convert this value to be set in the clock correction register. For how to convert, refer to “(a) Calculation
example 1”.
*2. Measurement value when 1 Hz clock pulse is output from the INT2 pin.
*3. Target value of average frequency when the clock correction function is used.
*4. Refer to Table 12.
(a) Calculation example 1
In case of current oscillation frequency actual measurement value = 1.000070 [Hz], target oscillation frequency =
1.000000 [Hz], B7 = 0 (Minimum resolution = 3.052 ppm)
1.000070
− 1.000000
( )
(
)
Correction value = 128 − Integral value
6
1.000070
×
3.052 × 10−
(
)
(
)
= 128 − Integral value (22.93)= 128 − 22 = 106
Convert the correction value “106” to 7-bit binary and obtain “1101010b”.
Reverse the correction value “1101010b” and set it to B6 to B0 of the clock correction register.
Thus, set the clock correction register:
(B7, B6, B5, B4, B3, B2, B1, B0) = (0, 1, 0, 1, 0, 1, 1, 0)
(2) If current oscillation frequency < target frequency (in case the clock is slow)
(Current oscillation frequency
actual measurement value)
−
(Target oscillation frequency)
+ 1
Correction value = Integral value
(Current oscillation frequency
actual measurement value)
×
(Minimum resolution)
Caution The figure range which can be corrected is that the calculated value is from 0 to 62.
(a) Calculation example 2
In case of current oscillation frequency actual measurement value = 0.999920 [Hz], target oscillation frequency =
1.000000 [Hz]. B7 = 0 (Minimum resolution = 3.052 ppm)
1.000000
− 0.999920
( )
(
)
Correction value = Integral value
+ 1
0.999920
(
×
3.052 × 10-6
(
)
)
= Integral value (26.21) + 1 = 26 + 1 = 27
Thus, set the clock correction register:
(B7, B6, B5, B4, B3, B2, B1, B0) = (1, 1, 0, 1, 1, 0, 0, 0)
(b) Calculation example 3
In case of current oscillation frequency actual measurement value = 0.999920 [Hz], target oscillation frequency =
1.000000 [Hz], B7 = 1 (Minimum resolution = 1.017 ppm)
1.000000
− 0.999920
( )
(
)
Correction value = Integral value
+ 1
0.999920
×
1.017 × 10-6
(
)
(
)
= Integral value (78.66) + 1
Thus, this calculated value exceeds the correctable range 0 to 62,
B7 = “1” (minimum resolution = 1.017 ppm) indicates the correction is impossible.
Seiko Instruments Inc.
25
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
2. Setting value for register and correction value
Table 13 Setting Value for Register and Correction Value (Minimum Resolution: 3.052 ppm (B0 = 0))
Correction Value
[ppm]
Rate
[s/day]
B7
B6
B5
B4
B3
B2
B1
B0
1
0
1
1
1
0
1
1
1
1
1
1
1
1
1
•
1
1
1
0
0
0
0
0
0
192.3
189.2
186.2
•
16.61
16.35
16.09
•
•
•
•
•
•
•
0
1
0
1
0
1
1
0
0
1
1
0
0
0
0
1
1
1
0
0
0
1
1
1
0
0
0
1
1
1
•
0
0
0
1
1
1
0
0
0
1
1
1
0
0
0
0
0
0
6.1
3.1
0
−3.1
−6.1
−9.2
•
0.53
0.26
0
−0.26
−0.53
−0.79
•
•
•
•
•
•
•
0
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
0
0
0
−189.2
−192.3
−195.3
−16.35
−16.61
−16.88
Table 14 Setting Value for Register and Correction Value (Minimum Resolution: 1.017 ppm (B0 = 1))
Correction Value
[ppm]
Rate
[s/day]
B7
B6
B5
B4
B3
B2
B1
B0
1
0
1
1
1
0
1
1
1
1
1
1
1
1
1
•
1
1
1
0
0
0
1
1
1
64.1
63.1
62.0
•
5.54
5.45
5.36
•
•
•
•
•
•
•
0
1
0
1
0
1
1
0
0
1
1
0
0
0
0
1
1
1
0
0
0
1
1
1
0
0
0
1
1
1
•
0
0
0
1
1
1
0
0
0
1
1
1
1
1
1
1
1
1
2.0
1.0
0
−1.0
−2.0
−3.0
•
0.18
0.09
0
−0.09
−0.18
−0.26
•
•
•
•
•
•
•
0
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
−63.1
−64.1
−65.1
−5.45
−5.54
−5.62
26
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
3. How to confirm setting value for register and result of correction
The S-35392A does not adjust the frequency of the crystal oscillation by using the clock-correction function. Therefore
users cannot confirm if it is corrected or not by measuring output 32.768 kHz. When the function to clock-correction is
being used, the cycle of 1 Hz clock pulse output from the
Figure 27.
pin changes once in 20 times or 60 times, as shown in
INT2
INT2 pin
(1 Hz output)
a
a
b
a
a
Once
19 times or 59 times
B0 = 0, a : 19 times, b : Once
B0 = 1, a : 59 times, b : Once
Figure 27 Confirmation of Correction Result
Measure a and b by using the frequency counter*1. Calculate the average frequency (Tave) based on the measurement
results.
B0 = 0, Tave = (a × 19 + b) ÷ 20
B0 = 1, Tave = (a × 59 + b) ÷ 60
Calculate the error of the clock based on the average frequency (Tave). The following shows an example for
confirmation.
Confirmation example: When B0 =0, 66h is set
Measurement results: a = 1.000080 Hz, b = 0.998493 Hz
Clock Correction Register Setting Value
Before correction 00 h (Tave = a)
Average Frequency [Hz] Per Day [s]
1.000080
86393
86399.9
After correction
66 h (Tave = (a × 19 + b) ÷ 20) 1.00000065
Calculating the average frequency allows to confirm the result of correction.
*1. Use a high-accuracy frequency counter of 7 digits or more.
Caution Measure the oscillation frequency under the usage conditions.
Seiko Instruments Inc.
27
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Serial Interface
The S-35392A receives various commands via I2C-bus serial interface to Read/Write data. Regarding transmission is as
follows.
1. Start condition
A start condition is when the SDA line changes “H” to “L” when the SCL line is in “H”, so that the access starts.
2. Stop condition
A stop condition is when the SDA line changes “L” to “H” when the SCL line is in “H”, and the access stops, so that the
S-35392A gets standby.
tSU.STA tHD.STA
tSU.STO
SCL
SDA
Start condition
Stop condition
Figure 28 Start/Stop Conditions
3. Data transfer and acknowledgment signal
Data transmission is performed for every 1-byte, after detecting a start condition. Transmit data while the SCL line is in
“L”, and be careful of spec of tSU.DAT and tHD. DAT when changing the SDA line. If the SDA line changes while the SCL line
is in “H”, the data will be recognized as start/stop condition in spite of data transmission. Note that by this case, the
access will be interrupted.
During data transmission, every moment receiving 1-byte data, the devices which work for receiving data send an
acknowledgment signal back. For example, as seen in Figure 29, in case that the S-35392A is the device working for
receiving data and the master device is the one working for sending data; when the 8-bit clock pulse falls, the master
device releases the SDA line. After that, the S-35392A sends an acknowledgment signal back, and set the SDA line to
“L” at the 9-bit clock pulse. The S-35392A does not output an acknowledgment signal is that the access is not being
done regularly.
SCL
8
9
(Input from
S-35392A)
1
tSU.DAT
tHD.DAT
SDA is released
High-Z
SDA
(Output from
master device)
Output acknowledgment
(“L” active)
SDA
High-Z
(Output from
S-35392A)
Start condition
tPD
Figure 29 Output Timing of Acknowledgment Signal
28
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
The followings are Read/Write in the S-35392A.
(1) Data Read in S-35392A
After detecting a start condition, the S-35392A receives device code and command. The S-35392A enters the
Read-data mode by the Read/Write bit “1”. The data is output from B7 in 1-byte. Input an acknowledgment signal
from the master device every moment that the S-35392A outputs 1-byte data. However, do not input an
acknowledgment signal (input NO_ACK) for the last data-byte output from the master device. This procedure
notifies the completion of Read. Next, input a stop condition to the S-35392A to finish access.
1-byte data
18
1
9
SCL
SDA
R/W
B7
0 1 1 0 0 0 0
1
B0
Device code + command
Input NO_ACK after the 1st byte
of data has been output.
: Output from S-35392A
: Input from master device
Figure 30 Example of Data Read 1 (1-Byte Data Register)
3-byte data
1
9
36
18
27
SCL
R/W
0 1 1 0 0 1 1
1
SDA
B0
B0
B7
B7
B7
B0
Device code + command
: Output from S-35392A
: Input from master device
Input NO_ACK after the 3rd byte of
data has been output.
Figure 31 Example of Data Read 2 (3-Byte Data Register)
Seiko Instruments Inc.
29
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
(2) Data Write in S-35392A
After detecting a start condition, S-35392A receives device code and command. The S-35392A enters the Write-data
mode by the Read/Write bit “0”. Input data from B7 to B0 in 1-byte. The S-35392A outputs an acknowledgment signal
(“L”) every moment that 1-byte data is input. After receiving the acknowledgment signal which is for the last byte-data,
input a stop condition to the S-35392A to finish access.
1-byte data
18
1
9
SCL
SDA
R/W
0 1 1 0 0 0 0 0
B7
B0
Device code + command
: Output from S-35392A
: Input from master device
Figure 32 Example of Data Write 1 (1-Byte Data Register)
3-byte data
18
36
1
9
27
SCL
R/W
0 1 1 0 0 1 1 0
SDA
B7
B0 B7
B0
B0
B7
Device code + command
: Output from S-35392A
: Input from master device
Figure 33 Example of Data Read 2 (3-Byte Data Register)
30
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
4. Data access
(1) Real-time data 1 access
72
63
1
9
18
SCL
R/W
0
1 1 0 0 1 0
SDA
B0
Second data
B7
B0
Year data
B7
Device code +
command
I/O mode switching
I/O mode switching
*1. Set NO_ACK = 1 in Read.
*2. Transmit ACK = 0 from the master device to the S-35392A in Read.
Figure 34 Real-Time Data 1 Access
(2) Real-time data 2 access
1
9
36
18
27
SCL
SDA
R/W
1
0
1 1 0 0 1
B0
B7
B7
B7
B0
B0
Second data
Device code +
command
Minute data
Hour data
I/O mode switching
I/O mode switching
*1. Set NO_ACK = 1 in Read.
*2. Transmit ACK = 0 from the master device to the S-35392A in Read.
Figure 35 Real-Time Data 2 Access
(3) Status register 1 access and status register 2 access
9
18
1
SCL
SDA
R/W
*1
1 1 0 0 0
0
B7
B0
Status data
Device code +
command
I/O mode switching
I/O mode switching
*1. 0 : Status register 1 selected, 1 : Status register 2 selected
*2. Set NO_ACK = 1 in Read.
Figure 36 Status Register 1 Access and Status Register 2 Access
Seiko Instruments Inc.
31
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
(4) INT1 register access and INT2 register access
In Read/Write the INT1 and INT2 registers, data varies depending on the setting of the status register 2. Be sure to
Read/Write after setting the status register 2. When setting the alarm by using the status register 2, these registers
work as 3-byte alarm time data registers, in other statuses, they work as 1-byte registers. When outputting the
user-set frequency, they are the data registers to set up the frequency.
Regarding details of each data, refer to “4. INT1 register and INT2 register” in “ Configuration of Register”.
Caution Users cannot use both functions of alarm 1 interrupt and the output of user-set frequency
simultaneously.
9
18
27
1
36
SCL
R/W
*1
1 1 0 1 0
0
B7
B0
B7
Minute data
B0
B7
B0
Device code +
command
Day of the
week data
Hour data
I/O mode switching
I/O mode switching
*1. 0 : INT1 register selected, 1 : INT2 register selected
*2. Set NO_ACK = 1 in Read.
*3. Transmit ACK = 0 from the master device to the S-35392A in Read.
Figure 37 INT1 Register Access and INT2 Register Access
9
18
1
SCL
SDA
R/W
*1
0
1 1 0 1 0
B7
B0
Device code +
command
Frequency
setting data
I/O mode switching
I/O mode switching
*1. 0 : INT1 register selected, 1 : INT2 register selected
*2. Set NO_ACK = 1 in Read.
Figure 38 INT1 Register and INT2 Register (Data Register for Output Frequency) Access
32
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
(5) Clock correction register access
1
9
18
SCL
SDA
R/W
0
1 1 0 1 1 0
B7
B0
Device code +
command
Clock
correction data
I/O mode switching
I/O mode switching
*1. Set NO_ACK = 1 in Read.
Figure 39 Clock Correction Register Access
(6) Free register access
1
9
18
SCL
R/W
0
1 1 0 1 1 1
SDA
B0
B7
Device code +
command
Free register
data
I/O mode switching
*1. Set NO_ACK = 1 in Read.
I/O mode switching
Figure 40 Free Register Access
Seiko Instruments Inc.
33
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Reset After Communication Interruption
In case of communication interruption in the S-35392A, for example, during communication the power supply voltage drops
so that only the master device is reset; the S-35392A does not operate the next procedure because the internal circuit
keeps the state prior to interruption. The S-35392A does not have a reset pin so that users usually reset its internal circuit by
inputting a stop condition. However, if the SDA line is outputting “L” (during output of acknowledgment signal or Read), the
S-35392A does not accept a stop condition from the master device. In this case, users are necessary to finish
acknowledgment output or Read the SDA line. Figure 41 shows how to reset. First, input a start condition from the master
device (The S-35392A cannot detect a start condition because the SDA line in the S-35392A is outputting “L”). Next, input a
clock pulse equivalent to 7-byte data access (63-clock) from the SCL line. During this, release the SDA line for the master
device. By this procedure, SDA I/O before interruption is finished, so that the SDA line in the S-35392A is released. After
that, inputting a stop condition resets the internal circuit so that restore the regular communication. This reset procedure is
recommended to perform at initialization of the system after rising the master device’s power supply voltage.
Start
condition
Stop
condition
Clocks equivalent to 7-byte data access
1
2
8
9
62
63
SCL
SDA
(Output from
master device)
“L” or High-Z
“L” or High-Z
SDA
(Output from
S-35392A)
“L”
“L”
High-Z
SDA
Figure 41 How to Reset
34
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Flowchart of Initialization at Power-on and Example of Real-time Data Set-up
Figure 42 shows the flowchart of initialization at power-on and an example of real-time data set-up. Regarding how to apply
power, refer to “ Power-on Detection Circuit and Register Status”. It is unnecessary for users to comply with this
flowchart of real-time data strictly. And if using the default data at initializing, it is also unnecessary to set up again.
START
Power-on
Wait for 0.5 s
Read status register 1
NO
POC = 1
YES
Initialization after power-on
Initialize
(status register 1 B7 = 1)
Read status register 1
NO
POC = 0
YES
NO
BLD = 0
YES
Set 24-hour/12-hour
display to status register 1
Read status register 1
NG
Confirm data in status
register 1
Example of real-time data setting
OK
Set real-time data 1
Read real-time data 1
Read status register 2
NO
TEST = 0
YES
END
Figure 42 Example of Initialization Flowchart
Seiko Instruments Inc.
35
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Examples of Application Circuits
VCC
10 kΩ
10 kΩ
System
power supply
VCC
32KO
VDD
INT2
CPU
S-35392A
SDA
VSS
SCL
XIN
XOUT
VSS
Cg
Caution 1. Because the I/O pin has no protective diode on the VDD side, the relation of VCC ≥ VDD is possible,
but pay careful attention to the specifications.
2. Start communication under stable condition after power-on the power supply in the system.
Figure 43 Application Circuit 1
System power
supply
10 kΩ
10 kΩ
VCC
32KO
INT2
VDD
VSS
CPU
S-35392A
SDA
SCL
XIN
XOUT
VSS
Cg
Caution Start communication under stable condition after power-on the power supply in the system.
Figure 44 Application Circuit 2
Caution The above connection diagrams do not guarantee operation. Set the constants after performing
sufficient evaluation using the actual application.
36
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Adjustment of Oscillation Frequency
1. Configuration of oscillator
Since crystal oscillation is sensitive to external noise (the clock accuracy is affected), the following measures are
essential for optimizing the oscillation configuration.
(1) Place the S-35392A, crystal oscillator, and external capacitor (Cg) as close to each other as possible.
(2) Increase the insulation resistance between pins and the substrate wiring patterns of XIN and XOUT.
(3) Do not place any signal or power lines close to the oscillator.
(4) Locating the GND layer immediately below the oscillator is recommended.
(5) Locate the bypass capacitor adjacent to the power supply pin of the S-35392A.
Parasitic capacitance*3
XIN
R
R
f
Oscillator internal constant
standard values:
C
g
Crystal oscillator: 32.768 kHz
d
CL
= 6 pF*1
XOUT
R
R
C
f
=
=
=
100 MΩ
100 kΩ
8 pF
Cg
= None*2 to 9.1 pF
d
d
Parasitic capacitance*3
Cd
S-35392A
*1. When setting the value for the crystal oscillator’s CL as 7 pF, connect Cd externally if necessary.
*2. Design the board so that the parasitic capacitance is 5 pF.
*3. The oscillator operates unless Cg is not connected. Note that the oscillation frequency is in the direction that it
advances.
Figure 45 Connection Diagram 1
S-35392A
1
2
3
4
8
7
6
5
XOUT
XIN
VSS
Crystal oscillator
Cg
Locate the GND layer in the
layer immediately below
Figure 46 Connection Diagram 2
Caution 1. When using the crystal oscillator with a CL exceeding the rated value (7 pF) (e.g : CL = 12.5 pF),
oscillation operation may become unstable. Use a crystal oscillator with a CL value of 6 pF or 7 pF.
2. Oscillation characteristics is subject to the variation of each component such as substrate parasitic
capacitance, parasitic resistance, crystal oscillator, and Cg. When configuring an oscillator, pay
sufficient attention for them.
Seiko Instruments Inc.
37
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
2. Measurement of oscillation frequency
When the S-35392A is turned on, a signal of 32.768 kHz is output from the 32KO pin. Turn the power on and measure the
signal with a frequency counter following the circuit configuration shown in Figure 47.
Remark If the error range is 1 ppm in relation to 32.768 kHz, the time is shifted by approximately 2.6 seconds per
month (calculated using the following expression).
10–6 (1 ppm) 60 seconds 60 minutes 24 hours 30 days 2.592 seconds
×
×
×
×
=
VDD
XIN
1 kΩ
1 kΩ
SDA
SCL
C
g
10 kΩ
S-35392A
XOUT
32KO
Frequency
counter
Open
or pull-up
INT2
VSS
Figure 47 Configuration of Oscillation Frequency Measurement Circuit
Caution 1. Use a high-accuracy frequency counter of 7 digits or more.
2. Measure the oscillation frequency under the usage conditions.
38
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
3. Adjustment of oscillation frequency
(1) Adjustment by setting Cg
Matching of the crystal oscillator with the nominal frequency must be performed with the stray capacitance on the
board included. Select a crystal oscillator and optimize the Cg value in accordance with the flowchart below.
START
Select a crystal
oscillator*1
YES
Variable
capacitance
Trimmer capacitor
NO
Set to center
Fixed capacitor
of variable
capacitance*3
Set C
g
NO
Frequency
YES
NO
C in
g
specification
YES
Change C
g
Make fine adjustment
of frequency using
variable capacitance
NO
Optimal
value*2
YES
END
*1. Request a crystal manufacturer for matching evaluation between the IC and a crystal. The recommended
crystal characteristic values are, CL value (load capacitance) = 6 pF, R1 value (equivalent serial resistance) = 50
kΩ max.
*2. The Cg value must be selected on the actual PCB since it is affected by stray capacitance. Select the external Cg
value in a range of 0 pF to 9.1 pF.
*3. Adjust the rotation angle of the variable capacitance so that the capacitance value is slightly smaller than the
center, and confirm the oscillation frequency and the center value of the variable capacitance. This is done in
order to make the capacitance of the center value smaller than one half of the actual capacitance value because a
smaller capacitance value increases the frequency variation.
Figure 48 Crystal Oscillator Setting Flow
Caution 1. The oscillation frequency varies depending on the ambient temperature and power supply
voltage. Refer to “ Characteristics (Typical Data)”.
2. The 32.768 kHz crystal oscillator operates more slowly at an operating temperature than higher
or lower 20 to 25 C. Therefore, it is recommended to set the oscillator to operate slightly faster
°
at normal temperature.
Seiko Instruments Inc.
39
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Product Name Structure
S-35392A
-
I8T1
G
Package name (abbreviation) and IC packing specification
I8T1: SNT-8A, Tape
Product name
Precautions
•
Although the IC contains a static electricity protection circuit, static electricity or voltage that exceeds the limit of the
protection circuit should not be applied.
•
Seiko Instruments Inc. assumes no responsibility for the way in which this IC is used in products created using this
IC or for the specifications of that product, nor does Seiko Instruments Inc. assume any responsibility for any
infringement of patents or copyrights by products that include this IC either in Japan or in other countries.
40
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
Characteristics (Typical Data)
(1) Standby current vs. VDD characteristics
(2) Current consumption vs. Input clock characteristics
Ta = 25°C, CL = 6 pF
Ta = 25°C, CL = 6 pF
1.0
0.8
50
45
40
35
VDD = 5.0 V
30
25
0.6
IDD1
[µA]
IDD2
[µA]
0.4
20
15
VDD = 3.0 V
0.2
0
10
5
0
2
3
4
0
100
200
300
400
500
10
6
0
1
5
6
SCL frequency [kHz]
V
DD [V]
(3) Standby current vs. Temperature characteristics
(4) Standby current vs. Cg characteristics
CL = 6 pF
Ta = 25°C, CL = 6 pF
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
VDD = 5.0 V
VDD = 5.0 V
IDD1
IDD1
[µA]
[µA]
VDD = 3.0 V
VDD = 3.0 V
0
25
Ta [°C]
50
−40 −25
75 85
0
2
4
6
8
Cg [pF]
(5) Oscillation frequency vs. Cg characteristics
(6) Oscillation frequency vs. VDD characteristics
Ta = 25°C, CL = 6 pF
Ta = 25°C, CL = 7.5 pF
100
80
60
40
20
50
40
30
20
10
0
−10
−20
−30
−40
−50
VDD = 5.0 V
∆f/f
[ppm]
∆f/f
[ppm]
0
VDD = 3.0 V
−20
−40
−60
−80
−100
0
2
4
6
8
10
0
2
3
4
1
5
Cg [pF]
VDD [V]
Seiko Instruments Inc.
41
2-WIRE REAL-TIME CLOCK
S-35392A
Rev.1.3_00
(7) Oscillation frequency vs. Temperature
characteristics
(8) Oscillation start time vs. Cg characteristics
Ta = 25°C
Cg = 7.5 pF
500
450
400
350
300
250
200
150
100
50
20
VDD = 5.0 V
0
−20
VDD = 3.0 V
−40
tSTA
[ms]
∆f/f
[ppm]
VDD = 5.0 V
VDD = 3.0 V
−60
−80
−100
−120
−140
0
8
10
0
2
4
6
−40 −25
75 85
0
25
Ta [°C]
50
Cg [pF]
(9) Output current characteristics 1 (VOUT vs. IOL1
)
(10) Output current characteristics 2 (VOUT vs. IOL2
SDA pin, Ta = 25 C
)
°
32KO pin, INT2 pin, Ta = 25°C
50
50
40
30
20
10
0
40
VDD = 5.0 V
VDD = 5.0 V
30
IOL1
IOL2
[mA]
[mA]
20
VDD = 3.0 V
VDD = 3.0 V
10
0
0
1
2
3
4
0
0.5
1
1.5
2
2.5
VOUT [V]
VOUT [V]
(11) BLD detection, release voltage, VDDT (Min) vs.
Temperature characteristics
CL = 6 pF
1.4
Release voltage
1.2
1.0
0.8
0.6
0.4
0.2
Detection voltage
VDDT (Min)
BLD
[V]
0
0
25
Ta [ C]
50
−
40
−
25
75 85
°
42
Seiko Instruments Inc.
1.97±0.03
6
5
8
7
+0.05
-0.02
0.08
1
2
3
4
0.5
0.48±0.02
0.2±0.05
No. PH008-A-P-SD-2.0
SNT-8A-A-PKG Dimensions
PH008-A-P-SD-2.0
TITLE
No.
SCALE
UNIT
mm
Seiko Instruments Inc.
+0.1
-0
4.0±0.1
2.0±0.05
0.25±0.05
ø1.5
0.65±0.05
ø0.5±0.1
4.0±0.1
2.25±0.05
5°
4 3 2 1
5 6 7 8
Feed direction
No. PH008-A-C-SD-1.0
TITLE
SNT-8A-A-Carrier Tape
PH008-A-C-SD-1.0
No.
SCALE
UNIT
mm
Seiko Instruments Inc.
12.5max.
9.0±0.3
Enlarged drawing in the central part
ø13±0.2
(60°)
(60°)
No. PH008-A-R-SD-1.0
SNT-8A-A-Reel
TITLE
No.
PH008-A-R-SD-1.0
5,000
SCALE
UNIT
QTY.
mm
Seiko Instruments Inc.
0.52
2.01
0.52
0.3
0.3
0.3
0.2
0.2 0.3
0.2
Caution Making the wire pattern under the package is possible. However, note that the package
may be upraised due to the thickness made by the silk screen printing and of a solder
resist on the pattern because this package does not have the standoff.
No. PH008-A-L-SD-3.0
SNT-8A-A-Land Recommendation
TITLE
No.
PH008-A-L-SD-3.0
SCALE
UNIT
mm
Seiko Instruments Inc.
·
·
The information described herein is subject to change without notice.
Seiko Instruments Inc. is not responsible for any problems caused by circuits or diagrams described herein
whose related industrial properties, patents, or other rights belong to third parties. The application circuit
examples explain typical applications of the products, and do not guarantee the success of any specific
mass-production design.
·
·
·
When the products described herein are regulated products subject to the Wassenaar Arrangement or other
agreements, they may not be exported without authorization from the appropriate governmental authority.
Use of the information described herein for other purposes and/or reproduction or copying without the
express permission of Seiko Instruments Inc. is strictly prohibited.
The products described herein cannot be used as part of any device or equipment affecting the human
body, such as exercise equipment, medical equipment, security systems, gas equipment, or any apparatus
installed in airplanes and other vehicles, without prior written permission of Seiko Instruments Inc.
Although Seiko Instruments Inc. exerts the greatest possible effort to ensure high quality and reliability, the
failure or malfunction of semiconductor products may occur. The user of these products should therefore
give thorough consideration to safety design, including redundancy, fire-prevention measures, and
malfunction prevention, to prevent any accidents, fires, or community damage that may ensue.
·
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