S-35399A03-J8T2G [SII]
2-WIRE REAL-TIME CLOCK; 2线实时时钟型号: | S-35399A03-J8T2G |
厂家: | SEIKO INSTRUMENTS INC |
描述: | 2-WIRE REAL-TIME CLOCK |
文件: | 总51页 (文件大小:569K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
Rev.1.0_00
2-WIRE REAL-TIME CLOCK
S-35399A03
The S-35399A03 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 0.34 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.
Moreover, this IC has a 24-bit binary up counter. This counter counts up every 60 sec from
power-on so that users are able to grasp the elapsed time from power-on up to 30 years.
Features
• Low current consumption :
0.34 µA typ. (VDD = 3.0 V, Ta = 25°C)
1.3 to 5.5 V
• Wide range of operating voltage :
• Built-in clock-correction function
• Built-in 24-bit binary up counter
• Built-in free user register
• 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 : 8-Pin SOP (JEDEC)
• 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
Tape
Package Name
8-Pin SOP (JEDEC)
Package
FJ008-A
Reel
FJ008-D
FJ008-D
Seiko Instruments Inc.
1
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Pin Configuration
8-Pin SOP (JEDEC)
Top view
INT1
XOUT
XIN
VDD
SDA
SCL
INT2
8
7
6
5
1
2
3
4
VSS
Figure 1 Pin Configuration (S-35399A03-J8T2G)
List of Pin
Table 1
Pin No.
1
Symbol
Description
Output pin for interrupt
signal 1
I/O
Configuration
Nch open-drain output
(no protective diode at VDD)
Output
INT1
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
Input pin for serial
clock
6
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-35399A03
Rev.1.0_00
Pin Functions
•
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.
(output for interrupt signal 1) pin
INT1
This pin outputs a signal of interrupt, or a clock pulse. By using the status register 2, users can select either of; alarm 1
interrupt, output of user-set frequency, per-minute edge interrupt, minute-periodical interrupt 1, minute-periodical
interrupt 2, or 32.768 kHz output. This pin has Nch open drain output.
•
(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 2
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
INT1, INT2
Figure 4
Pin,
Pin
INT2
INT1
Seiko Instruments Inc.
3
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Block Diagram
XIN
Oscillator
XOUT
Divider,
timing generator
INT1 controller
Alarm expansion
register 1
INT1 register
Clock correction
register
INT1
Status
register 1
Comparator 1
Day of
week
Second Minute Hour
Day Month Year
Status
register 2
Real-time data register
Free register 1
Free register 2
Free register 3
Comparator 2
INT2
Alarm expansion
register 2
INT2 register
Shift register
INT2 controller
24-bit
binary
SDA
SCL
Serial
interface
up counter
Low power
Power-on
detector
supply voltage
detector
VDD
VSS
Constant-
voltage circuit
Figure 5
4
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Absolute Maximum Ratings
Table 2
Applicable Pin
Parameter
Power supply voltage
Input voltage
Symbol
VDD
VIN
Rating
Unit
V
V
−
V
V
V
SS − 0.3 to VSS + 6.5
SS − 0.3 to VSS + 6.5
SS − 0.3 to VSS + 6.5
SCL, SDA
Output voltage
VOUT
SDA,
,
V
INT1 INT2
Operating ambient
Topr
Tstg
−
−40 to +85
°C
temperature*1
Storage temperature
−
−55 to +125
°C
*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
Min.
1.3
Typ.
3.0
Max.
5.5
Unit
V
Power supply voltage *1
Time keeping power
supply voltage *2
VDDT
Ta = −40 to +85°C
V
DET − 0.15
−
5.5
7
V
Crystal oscillator CL value 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
Parameter
Oscillation start voltage VSTA
°C, VDD = 3.0 V, VSS = 0 V, SP-T2A crystal oscillator (CL = 6 pF, 32.768 kHz) manufactured by Seiko Instruments Inc.)
Symbol
Conditions
Within 10 seconds
Min.
1.1
−
Typ.
−
−
Max.
5.5
1
Unit
V
s
Oscillation start time
IC-to-IC frequency
deviation*1
tSTA
−
δIC
−
−10
−
+10
ppm
Frequency voltage
δV
Cg
Cd
VDD = 1.3 to 5.5 V
−3
−
−
−
8
+3
9.1
−
ppm/V
pF
deviation
External capacitance
Internal oscillation
capacitance
Applied to XIN pin
Applied to XOUT pin
−
pF
*1. Reference value
Seiko Instruments Inc.
5
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
DC Electrical Characteristics
Table 5 DC Characteristics (VDD = 3.0 V)
(Ta = −40 to +85°C, VSS = 0 V, SP-T2A crystal oscillator (CL = 6 pF, 32.768 kHz, Cg = 9.1 pF) manufactured by Seiko Instruments Inc.)
Parameter
Current consumption 1
Symbol Applicable Pin
Conditions
Min.
−
Typ.
0.34
Max.
0.97
Unit
µA
IDD1
−
Out of communication
Out of communication
(when 32.768 kHz is
Current consumption 2
IDD2
−
−
0.60
1.47
µ
A
output from
pin)
INT1
During communication
(SCL = 100 kHz)
VIN = VDD
Current consumption 3
IDD3
−
−
9
14
µ
A
Input current leakage 1 IIZH
Input current leakage 2 IIZL
SCL, SDA
SCL, SDA
−
−
0.5
0.5
−
−
0.5
0.5
µ
µ
A
A
VIN = VSS
SDA,
INT2
SDA,
INT2
SCL, SDA
SCL, SDA
,
,
INT1
Output current leakage 1 IOZH
V
OUT = VDD
−
0.5
−
−
0.5
µ
µ
A
INT1
Output current leakage 2 IOZL
VOUT = VSS
−0.5
0.5
A
Input voltage 1
Input voltage 2
VIH
VIL
−
−
0.8
VSS
×
−
VDD
0.3
−
−
VSS + 5.5
V
V
mA
mA
0.2
×
−
−
VDD
Output current 1
Output current 2
IOL1
IOL2
INT1 INT2
SDA
VOUT = 0.4 V
3
5
5
10
,
VOUT = 0.4 V
Power supply voltage
detection voltage
VDET
−
−
0.65
1
1.35
V
Table 6 DC Characteristics (VDD = 5.0 V)
(Ta = −40 to
Parameter
Current consumption 1
+85°C, VSS = 0 V, SP-T2A crystal oscillator (CL = 6 pF, 32.768 kHz, Cg = 9.1 pF) manufactured by Seiko Instruments Inc.)
Symbol Applicable Pin
Conditions
Min.
−
Typ.
0.36
Max.
1.18
Unit
µA
IDD1
−
Out of communication
Out of communication
(when 32.768 kHz is
Current consumption 2
IDD2
−
−
0.82
2.17
µ
A
output from
pin)
INT1
During communication
(SCL = 100 kHz)
VIN = VDD
Current consumption 3
IDD3
−
−
20
30
µ
A
Input current leakage 1 IIZH
Input current leakage 2 IIZL
SCL, SDA
SCL, SDA
−
−
0.5
0.5
−
−
0.5
0.5
µ
µ
A
A
VIN = VSS
SDA,
INT2
SDA,
INT2
SCL, SDA
SCL, SDA
,
,
INT1
Output current leakage 1 IOZH
V
OUT = VDD
−
0.5
−
−
0.5
µ
A
INT1
Output current leakage 2 IOZL
VOUT = VSS
−0.5
0.5
µA
Input voltage 1
Input voltage 2
VIH
VIL
−
−
0.8 × VDD
SS − 0.3
−
−
VSS + 5.5
0.2 × VDD
V
V
V
Output current 1
Output current 2
IOL1
IOL2
INT1 INT2
SDA
V
OUT = 0.4 V
5
6
8
13
−
mA
mA
,
VOUT = 0.4 V
−
Power supply voltage
detection voltage
VDET
−
−
0.65
1
1.35
V
6
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
AC Electrical Characteristics
VDD
Table 7 Measurement Conditions
Input pulse voltage
Input pulse rise/fall time
VIH = 0.8 × VDD, VIL = 0.2 × 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-35399A03)
tBUF
tPD
SDA
(Output from
S-35399A03)
Figure 7 Bus Timing
Seiko Instruments Inc.
7
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_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-35399A03. Next, the
master device transmits 4-bit device code “0110” or “0111”, and 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-35399A03. The master device generates an acknowledgment signal for every
1-byte. Regarding details, refer to “ Serial Interface”. Device code “0110” is compatible with the SII S-35390A/392A as
software. Regarding details, refer to “2. Configuration of command”.
Read/Write bit
Start condition
Acknowledgment bit
Device code
Command
C1
STA
0
1
1
0 / 1
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-35399A03
Rev.1.0_00
2. Configuration of command
13 types of command are available for the S-35399A03, The S-35399A03 does Read/Write the various registers by
inputting these codes and commands. The S-35399A03 does not perform any operation with any codes and commands
other than those below.
Table 9 Command List
Command
Description
Status register 1 access
Status register 2 access
Data
Code
C2 C1 C0
B7
RESET
B6
12/24
B5
B4
B3
B2
B1
B0
*1
0
0
0
0
0
1
SC0*2 SC1*2 INT1*3 INT2*3 BLD*4 POC*4
INT2FE INT2ME
INT1FE INT1ME INT1AE 32kE
INT2AE TEST*5
Y40
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
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
m20
s20
H20
m20
s20
AM/PM
m40
s40
AM/PM
m40
s40
*6
*6
−
*6
−
−
Real-time data 2 access
(hour data to)
*6
*6
−
INT1 register access
*6
*6
*6
*6
−
W1
H1
m1
W2
H2
m2
W4
H4
m4
−
−
−
A1WE
A1HE
A1mE
(alarm time 1: week/hour/minute)
(INT1AE = 1, INT1ME = 0,
INT1FE = 0)
0110
H8
m8
H10
m10
H20
m20
AM/PM
m40
INT1 register access
SC2 *2 SC3 *2 SC4 *2
(output of user-set frequency)
(INT1ME = 0, INT1FE = 1)
INT2 register access
1 Hz
2 Hz
4 Hz
8 Hz
16 Hz
*6
*6
*6
*6
−
W1
H1
m1
W2
H2
m2
W4
H4
m4
−
−
−
A2WE
A2HE
A2mE
(alarm time 2: week/hour/minute)
(INT2AE = 1, INT2ME = 0,
INT2FE = 0)
H8
m8
H10
m10
H20
m20
AM/PM
m40
1
0
1
INT2 register access
1 Hz
2 Hz
4 Hz
8 Hz
16 Hz SC5 *2 SC6 *2 SC7 *2
(output of user-set frequency)
(INT2ME = 0, INT2FE = 1)
Clock correction register access
Free register 1 access
1
1
1
1
0
1
V0
F10
V1
F11
V2
F12
V3
F13
V4
V5
F15
C2M
C8k
C32
F25
F35
Y20
V6
F16
C4M
C16k
C64
F26
F36
Y40
V7
F17
C8M
C32k
C128
F27
F14
C64k C128k C256k C512k C1M
C256 C512
C1
F20
F30
Y1
0
0
0
Up counter access *7
C1k
C4
F22
F32
Y4
C2k
C8
F23
F33
Y8
M8
D8
Y8
M8
D8
C4k
C16
F24
F34
Y10
M10
D10
Y10
M10
D10
C2
F21
F31
Y2
M2
D2
0
0
0
1
1
0
Free register 2 access
Free register 3 access
F37
Y80
A1YE A1ME
0111
Alarm expansion register 1 access
(alarm time 1 : year/month/day)
*6
1
0
0
M1
D1
M4
D4
−
*6
D20
Y20
−
A1DE
Y80
Y1
Y2
Y4
Y40
Alarm expansion register 2 access
(alarm time 2 : year/month/day)
*6
1
0
1
M1
M2
M4
−
A2YE A2ME
*6
D1
D2
D4
D20
−
A2DE
*1. Write-only flag. The S-35399A03 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.
*7. The up counter is a Read-only register.
Seiko Instruments Inc.
9
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_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 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)
s2
s4
s8
s10
s20
s40
0
s1
B7
B0
Figure 9 Real-Time Data Register
10
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Year data (00 to 99): Y1, Y2, Y4, Y8, Y10, Y20, Y40, Y80
Sets the lower two digits in 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.
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2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_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, B3 : INT2, 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 interrupt function has come. The INT1 flag in “1” at alarm 1 interrupt mode, the INT2 flag
in “1” at alarm 2 interrupt mode. This flag is Read-only. This flag is read once, is set to “0” automatically.
B4, B5 : SC1, SC0
These flags configure a 2-bit SRAM type register that 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-35399A03
Rev.1.0_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
INT1FE
R/W
INT1ME
R/W
INT1AE
R/W
32kE
R/W
INT2FE
R/W
INT2ME
R/W
INT2AE
R/W
TEST
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 an
INT2
alarm 2 interrupt, set alarm interrupt mode, then access the INT2 register and the alarm expansion register 2.
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 : 32kE, B5 : INT1AE, B6 : INT1ME, B7 : INT1FE
These bits are used to select the output mode for the
pin. Table 11 shows how to select the mode. To use an
INT1
alarm 1 interrupt, set alarm interrupt mode, then access the INT1 register and the alarm expansion register 1.
Table 11 Output Modes for
Pin
INT1
32kE
INT1AE
0
INT1ME
INT1FE
Pin Output Mode
INT1
0
0
0
0
0
0
1
0
0
1
1
0
1
0
1
0
1
0
1
No interrupt
*1
−
−
Output of user-set frequency
Per-minute edge interrupt
Minute-periodical interrupt 1 (50% duty)
Alarm 1 interrupt
Minute-periodical interrupt 2
32.768 kHz output
*1
0
1
1
*1
*1
*1
−
−
−
*1. Don’t care (Both of 0 and 1 are acceptable).
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S-35399A03
Rev.1.0_00
4. INT1 register and INT2 register
The INT1 and INT2 registers are to set up the output of user-set frequency, or to set up alarm interrupt. Users are able
to switch the output mode by using the status register 2. If selecting to use the output mode for alarm interrupt by
status register 2; this register works as the alarm-time data register. If selecting the output of user-set frequency by
status register 2; this register works as the data register to set the frequency for clock output. From each INT1 and
INT2 pin, a clock pulse and alarm interrupt are output.
(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
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. Regarding set-up of year, month, day, refer to “9. Alarm expansion register 1 and alarm
expansion register 2”
.
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 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 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-35399A03
Rev.1.0_00
(2) Output of user-set frequency
The INT1 and INT2 registers are 1-byte data registers 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. SC2 to SC4 in the INT1 register,
and SC5 to SC7 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
2 Hz
R/W
4 Hz
R/W
8 Hz
R/W
16 Hz
R/W
SC2
R/W
SC3
R/W
SC4
R/W
R/W: Read/Write
Figure 13 INT1 Register (Data register for output frequency)
B6
B5
B4
B3
B2
B1
B0
B7
1 Hz
R/W
2 Hz
R/W
4 Hz
R/W
8 Hz
R/W
16 Hz
R/W
SC5
R/W
SC6
R/W
SC7
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
INT1 pin or
INT2 pin output
Status register 2
Set to INT1FE or INT2FE = 1
•
Figure 15 Example of output from INT1 register (Data register for output frequency)
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Rev.1.0_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
V0
V1
V2
V3
V4
V5
V6
V7
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 registers 1 to 3
These free registers are 1-byte SRAM type registers that can be set freely by users.
B6
B5
B4
B3
B2
B1
B0
B7
Fx0
Fx1
Fx2
Fx3
Fx4
Fx5
Fx6
Fx7
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W: Read/Write
x: 1 to 3
Figure 17 Free Register
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Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
7. Up counter
The up counter is a 24-bit Read-only register. It starts binary counting from “000000h” from power-on and continues
counting as long as power is being applied. It continues counting when initialization, instead of returning to “000000h”. At
power-on, registers are cleared by the power-on detector so that the up counter is cleared to “000000h”. If the power-on
detector does not operate successfully, the counter may start from the indefinite status. For successful operation of the
power-on detector, refer to “ Power-on Detection Circuit and Register Status”. Regarding the operation timing of the
up counter, refer to “ Up-Count Operation”.
C64k C128k C256k
B7
C512k C1M C2M C4M
C8M
B0
C256 C512 C1k
B7
C8k
C2k
C16k
C4k
C32k
B0
C1
B7
C2
C4
C8
C16
C64 C128
B0
C32
Figure 18 Up Counter
Table 12 Example of Count Value and Read Data in Register
Count Value
Read data in register
000001h
000002h
000080h
000040h
•
•
•
•
•
•
EFFFFFh
F7FFFFh
•
•
•
•
•
•
FFFFFFh
FFFFFFh
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2-WIRE REAL-TIME CLOCK
S-35399A03
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8. Alarm expansion register 1 and alarm expansion register 2
The alarm expansion register 1 and 2 are 3-byte registers. They are expansion registers for the INT1 and INT2 registers
which output alarm interrupt. Users are able to set the alarm time; the data of year, month, day. The configuration of
register is expressed by BCD code as well as the data register of year, month, day in the real-time register.
Alarm expansion register 1
Alarm expansion register 2
Y1
B7
Y1
B7
Y2 Y4 Y8 Y10 Y20 Y40 Y80
B0
Y2 Y4
Y8 Y10 Y20 Y40 Y80
B0
M2
M2
M1
B7
M4 M8 M10
0
A1YE A1ME
M1
B7
M4 M8 M10
0
A2YE A2ME
B0
B0
D1 D2
B7
D4 D8 D10 D20
0
A1DE
D1
B7
D2 D4 D8 D10 D20
A2DE
0
B0
B0
Figure 19 Alarm Expansion Register 1 and Alarm Expansion Register 2
To make the year data of alarm expansion register 1 valid, set A1YE to “1”. For the month data, set A1ME to “1”, for the
day data, set A1DE to “1”. Set as well A2ME, A2YE, A2DE in the alarm expansion register 2. Regarding how to set the
data of day of the week, hour, and minute, refer to “(1) Alarm interrupt” in “4. INT1 register and INT2 register”.
Setting example: Setting alarm time “January 31, 2015” in the alarm expansion register 1
Writing to alarm expansion register 1
Year
Month
Day
1
1
1
0
0
0
1
0
0
0
0
0
1
0
1
0
−
1
0
1
−
0
1
1
*1
*1
B7
B0
*1. Don’t care (Both of 0 and 1 are acceptable.)
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Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Power-on Detector and Register Status
The power-on detection circuit operates by power-on the S-35399A03, 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”
INT2 register :
“00h”
Clock correction register :
Free register 1 :
“00h”
“00h”
Free register 2 :
“00h”
Free register 3 :
“00h”
Up counter :
“00 00 00h”
“00h”
Alarm expansion register 1 :
Alarm expansion register 2 :
“00h”
“1” is set in the POC flag (B0 in the status register 1) to indicate that power has been applied. To correct the oscillation
frequency, the status register 2 goes in the mode the output of user-set frequency, so that 1 Hz clock pulse is output from
the INT1 pin. When “1” is set in the POC flag, be sure to initialize. The POC flag is set to “0” due to initialization so that the
output of user-set frequency mode is cleared. (Refer to “ Register Status After Initialization”.)
For the regular operation of power-on detection circuit, the period to power-up the S-35399A03 is that the voltage reaches
1.3 V within 10 ms after setting the IC’s power supply voltage at 0 V. When the power-on detection circuit is not working
normally is; the POC flag (B0 in the status register) is not in “1”, or 1 Hz is not output from the INT1 pin. In this case,
power-on the S-35399A03 once again because the internal data may be in the indefinite status.
Do not transmit data immediately after power-on at least one 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-35399A03.
Figure 20 How to raise the power supply voltage
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2-WIRE REAL-TIME CLOCK
S-35399A03
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Register Statuses 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 21.)
Status register 2 :
INT1 register :
INT2 register :
“00h”
“00h”
“00h”
Clock correction register :
Free register 1 :
“00h”
“00h”
Free register 2 :
“00h”
Free register 3 :
“00h”
Up counter :
Is not initialized and continues counting.
Alarm expansion register 1 :
Alarm expansion register 2 :
“00h”
“00h”
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
0
0 1 1 0 0 0 0 0
1
L L L L
L
H
0 1 1 0 0 0 0
1
L L
Code + command
Code + comman
B5
B7 B5 : Not reset
B7
Write “1” to reset flag and SC0.
: Output from S-35399A03
: Input from master device
Figure 21 Data of Status Register 1 at Initialization
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Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Low Power Supply Voltage Detection Circuit
The S-35399A03 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, the internal circuit may be in the indefinite status. In
this case, be sure to initialize the circuit.
VDD
Hysteresis width
0.15 V approximately
Release voltage
Detection voltage
BLD flag
reading
1 s
1 s
Stop
Stop
Stop
15.6 mm
Sampling pulse
BLD flag
Figure 22 Timing of Low Power Supply Voltage Detection Circuit
Circuits Power-on and Low Power Supply Voltage Detection
Figure 23 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 23 POC Flag and BLD Flag
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2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Correction of Nonexistent Data and End-of-Month
When users write the real-time data, the S-35399A03 checks it. In case that the data is invalid, the S-35399A03 does the
following procedures.
1. Processing of nonexistent data
Table 13 Processing of Nonexistent Data
Register
Year data
Month data
Day data
Day of 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-35399A03
Rev.1.0_00
INT1, INT2 Pin Output Modes
These are selectable for the output mode for INT1 and INT2 pins;
Alarm interrupt, the output of user-set frequency, per-minute edge interrupt output, minute-periodical interrupt output 1. In
the INT1 pin output mode, in addition to the above modes, minute-periodical interrupt output 2 and 32.768 kHz output are
also selectable.
To swith the output mode, use the status register 2. Refer to “3. status register 2” in “ Configuration of Register”.
When switching the output mode, be careful of the output status of the pin. Especially, when using alarm interrupt/output of
frequency, switch the output mode after setting “00h” in the INT1/INT2 register. In 32.768 kHz output/per-minute edge
interrupt output/minute-periodical interrupt output, it is unnecessary to set data in the INT1/INT2 register for users.
Refer to the followings regarding each operation of output modes.
1. Alarm interrupt output
Alarm interrupt output is the function to output “L” from the INT1/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 INT1AE/INT2AE in the status register 2.
To set the alarm time, set the data of day of the week, hour, minute in the INT1/INT2 register, set the data of year, month,
day in the alarm expansion register 1 or 2. Refer to “4. INT1 register and INT2 register” and “9. Alarm expansion
register 1 and alarm expansion register 2” in “ Configuration of Register”.
Alarm setting of “Y (year), M (month), D (day), W (day of week), H (hour), m (minute)”
Status register 2 setting
• INT1 pin output mode
32kE = 0, INT1ME = INT1FE = 0
• INT2 pin output mode
INT2ME = INT2FE = 0
INT1 register
INTx register alarm enable flag
• AxHE = AxmE = AxWE = "1"
Alarm expansion register x alarm enable flag
• AxYE = AxME = AxDE = "1"
Alarm expansion register 1
Alarm expansion register 2
INT2 register
mx
Hx
Wx
Dx
Mx
Yx
Comparator
Alarm interrupt
Second Minute Hour Week Day Month Year
Real-time data
Y (year), M (month), D (day), W (day of week)
59 s
Real-time data
INT1AE/INT2AE
INT1 pin/INT2 pin
H h 00m 00 s
01 s
H h (m + 1) m 00 s
H h (m − 1) m 59 s
Change by program
Change by program
Change by program
*1
Alarm time matches
OFF
Period when alarm time matches
*1. If users clear INT1AE/INT2AE once; “L” is not output from the INT1/INT2 pin by setting INT1AE/INT2AE
enable again, within a period when the alarm time matches real-time data.
Figure 24 Alarm Interrupt Output Timing (1/2)
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2-WIRE REAL-TIME CLOCK
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Rev.1.0_00
Alarm setting of “H (hour)”
Status register 2 setting
INTx register alarm enable flag
AxHE = AxmE = AxWE = "1"
Alarm expansion register x alarm enable flag
AxYE = AxME = AxDE = "1"
•
INT1 pin output mode
32kE = 0, INT1ME = INT1FE = 0
INT2 pin output mode
•
•
•
INT2ME = INT2FE = 0
INT1 register
INT2 register
Alarm expansion register 1
Alarm expansion register 2
mx
Hx
Wx
Dx
Mx
Yx
Alarm interrupt
Comparator
Second Minute Hour Week Day Month Year
Real-time data
Real-time data
H h 00 m 00 s
01 s
59 s
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
Change by program
INT1AE/INT2AE
*1
*1
Alarm time matches
Alarm time
matches*2
OFF
OFF
INT1 pin/INT2 pin
Period when alarm time matches
*1. If users clear INT1AE/INT2AE once; “L” is not output from the INT1/INT2 pin by setting INT1AE/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 INT1/INT2 pin when the minute is counted up.
Figure 25 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
INT1/INT2 pin, in the AND-form. Set up the data of frequency in the INT1/INT2 register.
Refer to “4. INT1 register and INT2 register” in “ Configuration of Register”.
Status register 2 setting
• INT1 pin output mode
32kE = 0, INT1AE = Don’t care (0 or 1), INT1ME = 0
• INT2 pin output mode
INT2AE = Don’t care (0 or 1), INT2ME = 0
Change by program
INT1FE/INT2FE
Free-run output starts
OFF
INT1 pin/INT2 pin
Figure 26 Output Timing of User-set Frequency
Seiko Instruments Inc.
24
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
3. Per-minute edge interrupt output
Per-minute edge interrupt output is the function to output “L” from the
/
pin, when the first minute-carry
INT1 INT2
processing is done, after selecting the output mode. To set the pin output to “H”, turn off the output mode of per-minute
edge interrupt. In the
input “0” in INT2ME.
pin output mode, input “0” in INT1ME in the status register 2. In the
pin output mode,
INT2
INT1
Status register 2 setting
• INT1 pin output mode
32kE = 0, INT1AE = Don’t care (0 or 1), INT1FE = 0
• INT2 pin output mode
INT2AE = Don’t care (0 or 1), INT2FE = 0
Change by program
INT1ME/INT2ME
INT1 pin/INT2 pin
Minute-carry
processing
Minute-carry processing
OFF
"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 27 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
pin, when the first minute-carry processing is done, after selecting the output mode.
/
INT1 INT2
Status register 2 setting
• INT1 pin output mode
32kE = 0, INT1AE = 0
Change by program (OFF)
• INT2 pin output mode
INT2AE = 0
INT1ME, INT1FE
INT2ME, INT2FE
Minute-carry
processing
Minute-carry
processing
Minute-carry
processing
Minute-carry
processing
Minute-carry
processing
INT1 pin/INT2 pin
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.
30 s
30 s
30 s
30 s
30 s
30 s
30 s
30 s
"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
Note that pin output is set to “L” by setting enable the output mode again.
/
pin is in “L”.
INT1 INT2
Figure 28 Timing of Minute-periodical Interrupt Output 1
Seiko Instruments Inc.
25
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
5. Minute-periodical interrupt output 2 (only in the INT1 pin output mode)
The output of minute-periodical interrupt 2 is the function to output “L”, for 7.9 ms, from the
pin, synchronizing with
INT1
the first minute-carry processing after selecting the output mode. However, in Read in the real-time data register, the
procedure delays at max. 0.5 sec thus output “L” from the
pin also delays at max. 0.5 sec. In Write in the real-time
INT1
data register, some delay is made in the output period due to Write timing and the second-data during Write.
(a) During normal operation
Minute-carry processing
Minute-carry processing
Minute-carry processing
INT1 pin
7.9 ms
7.9 ms
7.9 ms
60 s
60 s
(b) During real-time data read
(Normal minute-
carry processing)
Minute-carry processing
Minute-carry processing Minute-carry processing
INT1 pin
0.5 s Max.
7.9 ms
7.9 ms
60 s
7.9 ms
60 s
Serial
communication
Real-time data Real-time
Real-time data Real-time
read command data reading read command data reading
(c) During real-time data write
Minute-carry processing
Minute-carry processing
Minute-carry processing
INT1 pin
7.9 ms
7.9 ms
30 s
7.9 ms
55 s
45 s
80 s
10 s
50 s
Real-time data
write timing
Second data of writing: "50" s
The output period is shorter.
Second data of writing: "10" s
The output period is longer.
Figure 29 Timing of Minute-periodical Interrupt Output 2
26
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
6. Operation of power-on detection circuit (only in the INT1 pin output mode)
When power is applied to the S-35399A03, the power-on detection operates to set “1” in the POC flag (B0 in the status
register 1). A 1 Hz clock pulse is output from the
pin.
INT1
Status register 2 setting
Change by reset command
• 32kE = 0, INT1AE = INT1ME = 0
INT1FE
INT1 pin
OFF
0.5 s
0.5 s
Figure 30 Output Timing of
Pin during Operation of Power-on Detection Circuit
INT1
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-35399A03 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-35399A03 corrects in the range of
−195.3 to +192.2 ppm (or of −65.1 to +64.1 ppm). (Refer to Table 14.) 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 14 Function to Clock-Correction
B0 = 0
B0 = 1
Adjustment
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
Seiko Instruments Inc.
27
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_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
/
pin.
INT1 INT2
*3. Target value of average frequency when the clock correction function is used.
*4. Refer to Table 14
.
(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.
28
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
2. Setting value for register and correction value
Table 15 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 16 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
Seiko Instruments Inc.
29
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
3. How to confirm setting value for register and result of correction
The S-35399A03 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
pin changes once in 20 times or 60 times, as shown in
INT1
Figure 31
.
INT1 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 31 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.
30
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Up-Count Operation
The up counter is a 24-bit read-only binary counter. This counter starts counting from “000000h” from power-on and returns
to “000000h” at the next clock after it has reached “FFFFFFh”. A clock pulse is a pulse that is output when the second-data
in the real-time data is “00h”. Therefore, some delay is made in the period that a clock pulse is being output due to Write
timing and Write data. The registers are not initialized unless power-on again, so that users are able to grasp the elapsed
time from power-on up to 30 years. Figure 32 shows the example of timing chart of up counter’s operation.
ON
Power supply
OFF
OFF
Write real-time
second data:
20 seconds
Write real-time
second data:
50 seconds
Clock pulse
of real-time
second data
"00h"
60 s
60 s
40 s
40 s
60 s
20 s 10 s
24-bit binary
up counter
000000 h
000001 h 000010 h
FFFFFF h 000000 h 000001 h
A clock pulse is
60 seconds or more.
A clock pulse is
60 seconds or less.
Figure 32 Timing Chart of 24-Bit Binary Up Counter
Seiko Instruments Inc.
31
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Serial Interface
The S-35399A03 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-35399A03 gets standby.
tSU.STA tHD.STA
tSU.STO
SCL
SDA
Start condition
Stop condition
Figure 33 Start/Stop Conditions
3. Data transmission 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 34, in case that the S-35399A03 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-35399A03 sends an acknowledgment signal back, and set the SDA line
to “L” at the 9-bit clock pulse. The S-35399A03 does not output an acknowledgment signal is that the access is not
being done regularly.
SCL
8
9
(Input from
1
S-35399A03)
tSU.DAT
tHD.DAT
SDA
SDA is released
High-Z
(Output from
master device)
Output acknowledgment
(“L” active)
SDA
(Output from
S-35399A03)
High-Z
Start condition
tPD
Figure 34 Output Timing of Acknowledgment Signal
32
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
The followings are Read/Write in the S-35399A03.
(1) Data Read in S-35399A03
After detecting a start condition, the S-35399A03 receives device code and command. The S-35399A03 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-35399A03 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-35399A03 to finish access.
1-byte data
18
1
9
SCL
SDA
R/W
B7
0 1 1 0 0 0 0
1
B0
Code + command
: Output from S-35399A03
: Input from master device
Input NO_ACK after the 1st byte
of data has been output.
Figure 35 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
Code + command
: Output from S-35399A03
: Input from master device
Input NO_ACK after the 3rd byte of data
has been output.
Figure 36 Example of Data Read 2 (3-Byte Data Register)
Seiko Instruments Inc.
33
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
(2) Data Write in S-35399A03
After detecting a start condition, S-35399A03 receives device code and command. The S-35399A03 enters the
Write-data mode by the Read/Write bit “0”. Input data from B7 to B0 in 1-byte. The S-35399A03 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-35399A03 to finish access.
1-byte data
18
1
9
SCL
SDA
R/W
B7
0 1 1 0 0 0 0 0
B0
Code + command
: Output from S-35399A03
: Input from master device
Figure 37 Example of Data Write 1 (1-Byte Data Register)
3-byte data
18
36
1
9
27
SCL
R/W
B7
0 1 1 0 0 1 1 0
SDA
B0 B7
B0
B0
B7
Code + command
: Output from S-35399A03
: Input from master device
Figure 38 Example of Data Read 2 (3-Byte Data Register)
34
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_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
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-35399A03 in Read.
Figure 39 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
Code +
B0
B7
Minute data
I/O mode switching
B7
B7
B0
Second data
B0
command
Hour data
I/O mode switching
*1. Set NO_ACK = 1 in Read.
*2. Transmit ACK = 0 from the master device to the S-35399A03 in Read.
Figure 40 Real-Time Data 2 Access
(3) Status register 1 access and status register 2 access
9
18
1
SCL
SDA
R/W
*1
0
1 1 0 0 0
B7
B0
Code +
command
Status data
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 41 Status Register 1 Access and Status Register 2 Access
Seiko Instruments Inc.
35
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_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 for the INT1 pin and INT2 pin and the
output of user-set frequency simultaneously.
9
18
27
1
36
SCL
SDA
R/W
*1
0
1 1 0 1 0
B7
B0
B7
Minute data
B0
B7
B0
Code +
command
Day of week data
I/O mode switching
Hour data
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-35399A03 in Read.
Figure 42 INT1 Register Access and INT2 Register Access
9
18
1
SCL
SDA
R/W
*1
0
1 1 0 1 0
B7
B0
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 43 INT1 Register and INT2 Register (Data Register for output frequency) Access
36
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
(5) Clock-correction register access
1
9
18
SCL
SDA
R/W
0
1 1 0 1 1 0
B7
B0
Code +
command
Clock
correction data
I/O mode switching
I/O mode switching
*1. Set NO_ACK = 1 in Read.
Figure 44 Clock-Correction Register Access
(6) Free register 1 access
1
9
18
SCL
R/W
0
1 1 0 1 1 1
SDA
B0
B7
Code +
command
Free register
data
I/O mode switching
I/O mode switching
*1. Set NO_ACK = 1 in Read.
Figure 45 Free Register 1 Access
(7) Up counter access
Access to the up counter is Read-only. Users cannot Write in this counter with Write operation.
9
36
1
18
27
SCL
SDA
Read only
0
1
1
1 0 0 0
1
B0
B0
B7
B7
Code + command
I/O mode switching
Count data
Count data
I/O mode switching
Figure 46 Up Counter Access
Seiko Instruments Inc.
37
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
(8) Free register 2 access and free register 3 access
18
1
9
SCL
SDA
R/W
*1
1 1 1 0
a
0
b
B0
B7
Code +
command
Free register
data
I/O mode switching
I/O mode switching
*1. To select register, use the following settings.
a
0
1
b
1
0
Register to select
Free register 2
Free register 3
*2. Set NO_ACK = 1 in Read.
Figure 47 Free Register 2 Access and Free Register 3 Access
(9) Alarm expansion register 1 access and alarm expansion register 2 access
Write in the alarm expansion register 1 (alarm expansion register 2) after setting the status register 2.
36
1
9
18
27
SCL
SDA
R/W
*1
0
1 1 1 1 0
B0
Month data
B7
B0
Second data
B7
B0
B7
Code +
command
Year data
I/O mode switching
I/O mode switching
*1. 0 : Alarm expansion register 1 access, 1 : Alarm expansion register 2 access
*2. Transmit ACK = 0 from the master device to the S-35399A03 in Read.
*3. Set NO_ACK = 1 in Read.
Figure 48 Alarm Expansion Register 1 Access and Alarm Expansion Register 2 Access
38
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Reset After Communication Interruption
In case of communication interruption in the S-35399A03, for example, during communication the power supply voltage
drops so that only the master device is reset; the S-35399A03 does not operate the next procedure because the internal
circuit keeps the state prior to interruption. The S-35399A03 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-35399A03 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 49 shows how to reset. First, input a start condition from the master
device (The S-35399A03 cannot detect a start condition because the SDA line in the S-35399A03 is outputting “L”). Next,
input a clock pulse equivalent to 1-byte data access (9-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-35399A03 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
Clocks equivalent to 1-byte data access
Stop condition
1
2
8
9
SCL
SDA
(Output from
master device)
High-Z
SDA
(Output from
S-35399A03)
“L”
“L”
“L” or High-Z
“L” or High-Z
High-Z
High-Z
SDA
Figure 49 How to Reset
Seiko Instruments Inc.
39
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Flowchart of Initialization at Power-on and Example of Real-time Data Set-up
Figure 50 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 50 Example of Initialization Flowchart
40
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Examples of Application Circuits
VCC
10 kΩ
10 kΩ
System
power supply
VCC
INT1
VDD
INT2
CPU
S-35399A03
SDA
VSS
SCL
XOUT
XIN
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 51 Application Circuit 1
System power
supply
10 kΩ
10 kΩ
VCC
INT1
INT2
VDD
VSS
CPU
S-35399A03
SDA
SCL
XIN
XOUT
VSS
Cg
Caution Start communication under stable condition after power-on the power supply in the system.
Figure 52 Application Circuit 2
Caution The above connection diagrams do not guarantee operation. Set the constants after performing
sufficient evaluation using the actual application.
Seiko Instruments Inc.
41
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_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-35399A03, 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-35399A03.
Parasitic capacitance Cpi
XIN
R
R
f
Oscillator internal constant
standard values:
C
g
Crystal oscillator: 32.768 kHz
C
C
C
L
= 6 pF*1
d
R
R
C
f
=
=
=
100 MΩ
100 kΩ
8 pF
XOUT
d
d
g
= 0 to 9.1 pF
pi, Cpo < 5 pF
Parasitic capacitance Cpo
C
d
S-35399A03
*1. When using a crystal oscillator with a CL value of 7 pF, externally connect Cd if necessary.
Figure 53 Connection Diagram 1
S-35399A03
1
2
3
4
8
7
6
5
Crystal oscillator
XOUT
XIN
Locate the GND layer in the layer
immediately below
VSS
Cg
Figure 54 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.
42
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
2. Measurement of oscillation frequency
When the S-35399A03 is turned on, the internal power-on detector operates and a signal of 1 Hz is output from the
INT1
pin to select the crystal oscillator and optimize the Cg value. Turn the power on and measure the signal with a frequency
counter following the circuit configuration shown in Figure 55
If 1 Hz signal is not output, the power-on detector does not operate normally. Turn off the power and then turn it on
again. For how to apply power, refer to Power-on Detector and Register Status”
.
“
.
Remark If the error range is 1 ppm in relation to 1 Hz, 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-35399A03
XOUT
INT1
Frequency
counter
Open
or pull-up
INT2
VSS
Figure 55 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 use operation conditions.
3. Since the 1 Hz signal continues to be output, initialization must be executed during normal
operation.
Seiko Instruments Inc.
43
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_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 56 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.
44
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Product Name Structure
S-35399A03
-
J8T2
G
Package name (abbreviation) and IC packing specification
J8T2: 8-Pin SOP(JEDEC), 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.
Seiko Instruments Inc.
45
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
Characteristics (Typical Data)
(1) Current consumption 1 (current consumption out of (2) Current consumption 2 (current consumption when
communication) vs. VDD characteristics
Ta = 25°C, CL = 6 pF, Cg = 5.1 pF
32.768 kHz is output) vs. VDD characteristics
Ta = 25°C, CL = 6 pF, Cg = 5.1 pF
1.0
0.8
0.6
0.4
0.2
0
1.0
0.8
0.6
I
DD1
IDD2
[µA]
[µA]
0.4
0.2
0
0
1
2
3
4
5
6
0
1
2
3
4
5
6
V
DD [V]
V
DD [V]
(3) Current consumption 3 (current consumption during (4) Current consumption 1 (current consumption out of
communication) vs. Input clock characteristics
communication) vs. Temperature characteristics
Ta = 25°C, CL = 6 pF, Cg = 5.1 pF
CL = 6 pF, Cg = 5.1 pF
1.0
90
0.9
0.8
0.7
0.6
80
70
V
DD = 5.0 V
60
50
40
30
20
10
0
I
DD3
I
DD1
0.5
0.4
0.3
0.2
0.1
0
V
DD = 5.0 V
DD = 3.0 V
[µA]
[µA]
V
VDD = 3.0 V
0
100 200 300 400 500
SCL [kHz]
−40 −25
0
25
Ta [°C]
50
75 85
(5) Current consumption 1 (current consumption out of (6) Oscillation frequency vs. Cg characteristics
communication) vs. Cg characteristics
Ta = 25°C, CL = 6 pF
Ta = 25°C, CL = 6 pF, Cg = 5.1 pF (reference)
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
60
40
20
V
DD = 5.0 V
IDD1
∆f/f
[ppm]
0
−20
−40
−60
[µA]
V
DD = 5.0 V
V
DD = 3.0 V
V
DD = 3.0 V
0
2
4
6
8
10
0
2
4
6
8
10
Cg
[pF]
Cg [pF]
46
Seiko Instruments Inc.
2-WIRE REAL-TIME CLOCK
S-35399A03
Rev.1.0_00
(7) Oscillation frequency vs. VDD characteristics
(8) Oscillation frequency vs. Temperature
characteristics
Ta = 25°C, CL = 6 pF, Cg = 5.1 pF (reference)
CL = 6 pF, Cg = 5.1 pF (reference)
DD = 5.0 V
50
20
0
V
40
30
20
10
−20
−40
VDD = 3.0 V
∆f/f
∆f/f
[ppm]
0
−60
[ppm]
−10
−20
−30
−40
−50
−80
−100
−120
−140
0
1
2
3
4
5
6
−40 −25
0
25
50
75 85
VDD [V]
Ta [°C]
(9) Oscillation start time vs. Temperature
characteristics (XOUT PIN MONITORED)
(10) Output current characteristics 1 (VOUT vs. IOL1)
Ta = 25°C, CL = 6 pF
pin, INT2 pin, Ta = 25°C
INT1
500
450
400
350
300
250
200
150
100
50
40
35
30
25
20
15
10
5
V
DD = 5.0 V
tSTA
I
OL1
[ms]
[mA]
V
DD = 5.0 V
VDD = 3.0 V
V
DD = 3.0 V
0
0
0
2
4
6
8
10
0
1
2
3
4
5
6
Cg [pF]
V
OUT [V]
(11) Output current characteristics 2 (VOUT vs. IOL2
)
(12) Low power supply voltage detection voltage
release voltage, and time keeping power supply
voltage (Min) vs. Temperature characteristics
SDA pin, Ta = 25°C
CL = 6 pF, Cg = 5.1 pF
70
1.4
Release voltage
1.2
60
VDD = 5.0 V
50
40
30
20
10
0
1.0
Detection voltage
0.8
I
OL2
V
DDT (Min)
V
DD
[mA]
[V]
0.6
0.4
0.2
0
V
DD = 3.0 V
0
1
2
3
4
5
6
−40 −25
0
25
50
75 85
VOUT [V]
Ta [°C]
Seiko Instruments Inc.
47
5.02±0.2
8
5
1
4
0.20±0.05
1.27
0.4±0.05
No. FJ008-A-P-SD-2.1
SOP8J-D-PKG Dimensions
FJ008-A-P-SD-2.1
TITLE
No.
SCALE
UNIT
mm
Seiko Instruments Inc.
4.0±0.1(10 pitches:40.0±0.2)
2.0±0.05
ø1.55±0.05
0.3±0.05
8.0±0.1
ø2.0±0.05
2.1±0.1
5°max.
6.7±0.1
8
5
1
4
Feed direction
No. FJ008-D-C-SD-1.1
SOP8J-D-Carrier Tape
FJ008-D-C-SD-1.1
TITLE
No.
SCALE
UNIT
mm
Seiko Instruments Inc.
60°
2±0.5
13.5±0.5
Enlarged drawing in the central part
ø21±0.8
2±0.5
ø13±0.2
No. FJ008-D-R-SD-1.1
SOP8J-D-Reel
TITLE
FJ008-D-R-SD-1.1
No.
SCALE
UNIT
QTY.
2,000
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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