Real-time Clock Module PT7C43390/43390C

PT7C43390/43390C
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Real-time Clock Module
Description
Features
The PT7C43390 is a CMOS I2C-bus real-time clock IC,
which operates with the very low current consumption
and in the wide range of operation voltage. The
operation voltage is 1.35 V to 5.5 V so that the RTC can
be used for various power supplies from main supply to
backup battery. 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.
The 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.
 Low current consumption: 0.3µA typ. (VDD=3.0V,
TA = 25°C)
 Wide operating voltage range: 1.35 to 5.5 V
 Minimum time keeping operation voltage: 1.25 V
 Built-in clock adjustment function
 Built-in free user register
 2-wire (I2C-bus) CPU interface
 Built-in alarm interrupter
 Built-in flag generator at power down or power on
 Auto calendar up to the year 2099, automatic leap
year calculation function
 Built-in constant voltage circuit
 Built-in 32 kHz crystal oscillator circuit
 Built-in 32 kHz crystal for PT7C43390C
 Package: SOIC-8L, TSSOP-8L, and TDFN2x3-8L
for PT7C43390; TDFN4x4-8L for PT7C43390C
Applications






Mobile game device, mobile phone
Industrial control
Electronic power meter
DVD recorder
Car navigation
IP Camera, DVR, NVR
Function Table
Item
Function
PT7C43390
PT7C43390C
External crystal
Integral crystal


2


2

1Hz,2Hz,4Hz
8Hz,16Hz
32kHz

1Hz,2Hz,4Hz
8Hz,16Hz
32kHz
2-wire I2C bus


Burst mode


IC test mode


Power-on detector


Power supply voltage detector


1
Oscillator
Source
2
Time
Time display
3
Interrupt
4
Programmable square wave output (Hz)
5
Communication
6
Control
*
Crystal
12-hour
24-hour
Alarm interrupt pin output
Timer interrupt output
7
Clock calibration


80
Free register access


2015-12-0001
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PT7C43390/43390C
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Real-time Clock Module
Pin Configuration
PT7C43390
PT7C43390C
1
VDD
INT1
8
2
XOUT
SDA
7
3
XIN
SCL
6
4
GND
INT2
PT7C43390
5
PT7C43390
1
INT1
VDD
8
2
XOUT
SDA
7
3
XIN
SCL
6
4
GND
INT2
5
INT1 1
8
VDD
XOUT 2
7
SDA
6
SCL
5
INT2
XIN
3
GND 4
INT1
1
NC1
2
NC2
3
P
1
P
2
8
VDD
7
SDA
6
SCL
5
INT2
GND
GND
4
TDFN2x3-8L
TSSOP-8L
SOIC-8L
TDFN4x4-8L
Pin Description
Pin No.
43390 43390C
Pin
Name
Type
1
1
INT1
O
2
-
XOUT
O
-
2
NC1
-
3
-
XIN
I
4
3
4
NC2
VSS
P
5
5
INT2
O
6
6
SCL
I
7
7
SDA
I/O
8
8
VDD
P
Description
Output for Interrupt Signal 1. 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.
Oscillator Circuit Output. Together with X1, 32.768kHz crystal is connected between
them. When 32.768kHz external input, X2 must be float.
No connected.
Oscillator Circuit Input. Together with X1, 32.768kHz crystal is connected between
them. Or external clock input.
No connected.
Negative power supply pin. Connects to GND.
Output for Interrupt Signal 2. This pin outputs a signal of interrupt, or a clock pulse. By
using the status register 2, users can select either of: alarm2 interrupt, output of user-set
frequency, or minute-periodical interrupt 1. This pin has NCH open drain output.
Serial clock input 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.
Serial Data Input/Output. This is a data input / output pin of 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.
Positive power supply pin. Connect this VDD pin with a positive power supply.
2015-12-0001
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PT7C43390/43390C
Real-time Clock Module
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Block Diagram
XIN
XOUT
INT1
Divider,
Timing generator
Oscillator
INT controller 1
INT register 1
Clock correction register
Comparator 1
Status register 1
Real-time data register
Second Minute Hour
Status register 2
Free register
Day of
Week
Day
Month
Year
Comparator 2
Low power supply
voltage detector
VDD
INT2
INT register 2
Power-on
detection circuit
Constant-voltage
circuit
INT controller 2
INT register 2
SDA
Serial
interface
VSS
SCL
PT7C43390
XOUT
32.768
kHz
XIN
CD
Oscillator
Divider,
Timing generator
INT1
INT register 1
INT controller 1
CG
Clock correction register
Comparator 1
Status register 1
Status register 2
Real-time data register
Second Minute Hour
Free register
VDD
Day of
Week
Day
Month
Year
Comparator 2
Low power supply
voltage detector
Power-on
detection circuit
Constant-voltage
circuit
INT register 2
INT register 2
VSS
INT2
INT controller 2
SDA
Serial
interface
SCL
PT7C43390C
2015-12-0001
PT0280-8
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12/11/15
PT7C43390/43390C
Real-time Clock Module
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Maximum Ratings
Stresses greater than those listed under MAXIMUM
RATINGS may cause permanent damage to the
device. This is a stress rating only and functional
operation of the device at these or any other conditions
above those indicated in the operational sections of
this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may
affect reliability.
Storage Temperature.................................................................................... -55oC to +125oC
Operating Temperature..................................................................................-40oC to +85oC
Power Supply Voltage........................................................................Vss-0.3V to Vss+6.5V
DC Input Voltage(SCL, SDA) .........................................................Vss-0.3V to Vss+6.5V
DC Output Voltage(SDA, INT1, INT2) .......................................Vss-0.3V to Vss+6.5V
Power Dissipation.......................................................... 250mW (depend on package)
Recommended Operating Conditions
Symbol
Parameter
CONDITIONS
Min
Typ
Max
Unit
VDD
Power supply voltage
TA = −40 to +85°C
1.35
3.0
5.5
V
Topr
Operating temperature
VDD =1.3 to 5.5 V
−40
+25
+85
°C
VDDT
Time keeping voltage range
TA = −40 to +85°C
1.25
-
5.5
V
VDDR
Register hold voltage
TA = −40 to +85°C
0.9
-
5.5
V
VDET
Power supply voltage detection voltage *1
TA = −40 to +85°C
0.70
1.05
1.40
V
-
6
12.5
pF
CL
Crystal oscillator CL value
-
*1. Power supply voltage detection voltage: Constantly maintains the relation of V DET > VDDRM (minimum data hold voltage).
Oscillation Characteristics
(For PT7C43390: TA = 25°C, VDD = 3.0 V, VSS = 0 V, crystal oscillator (CL = 6pF, 32.768 kHz).)
Symbol
Conditions
Min.
Typ.
Max.
Unit
Within 10 seconds
1.1
-
5.5
V
Oscillation start time
-
-
-
3
s
δIC
IC to IC frequency deviation
-
-10
-
+10
ppm
δV
Frequency voltage deviation
VDD =1.35 to 5.5 V
-3
-
+3
ppm
VSTA
-
Parameter
Oscillation start voltage
(For PT7C43390C: TA = 25°C, VDD = 3.0 V, VSS = 0 V.)
Symbol
Conditions
Min.
Typ.
Max.
Unit
Within 10 seconds
1.1
-
5.5
V
Oscillation start time
-
-
-
3
s
δIC
IC to IC frequency deviation
-
-10
-
+10
ppm
f / f
Frequency tolerance
-
-30
-
+30
ppm
VDD =1.3 to 5.5 V
-3
+3
ppm
±5
ppm/year
VSTA
-
Parameter
Oscillation start voltage
δV
Frequency voltage deviation
fa
Aging
First year
2015-12-0001
PT0280-8
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12/11/15
PT7C43390/43390C
Real-time Clock Module
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DC Electrical Characteristics
( TA = -40°C to +85°C; VSS = 0V, crystal oscillator CL = 6pF, 32.768KHz, unless otherwise noted.)
Pin
Symbol
Parameter
Test Conditions
Min
Typ
Max
Unit
-
0.3
0.6
µA
VDD = 3.0V
IDD1
Current consumption 1
VDD
Out of communication
During communication
(SCL=100kHz)
VIN = VDD
IDD2
Current consumption 2
VDD
-
3.5
8
µA
IIZH
Input high leakage current
SCL,SDA
-0.5
-
+0.5
µA
IIZL
Input low leakage current
IOZH
Output high leakage current
IOZL
Output low leakage current
VIH
Input high voltage
SCL,SDA
SDA,INT1,
INT2
SDA,INT1,
INT2
SCL,SDA
VIN = VSS
-0.5
-
+0.5
µA
VOUT = VDD
-0.5
-
+0.5
µA
VOUT = VSS
-0.5
-
+0.5
µA
-
0.8VDD
-
-
V
VIL
Input low voltage
SCL,SDA
-
-
-
0.2VDD
V
IOL1
Output low current 1
INT1
VOUT = 0.4V
1.0
1.6
-
mA
INT2
VOUT = 0.4V
5
8
-
mA
IOL2
Output low current 2
SDA
VOUT = 0.4V
5
8
-
mA
Out of communication
During communication
(SCK=100kHz)
VIN = VDD
-
0.35
0.7
µA
-
7
14
µA
-0.5
-
+0.5
µA
VIN = VSS
-0.5
-
+0.5
µA
VOUT = VDD
-0.5
-
+0.5
µA
VOUT = VSS
-0.5
-
+0.5
µA
-
0.8VDD
-
-
V
VDD = 5.0V
IDD1
Current consumption 1
VDD
IDD2
Current consumption 2
VDD
IIZH
Input high leakage current
SCL,SDA
IIZL
Input low leakage current
IOZH
Output high leakage current
IOZL
Output low leakage current
VIH
Input high voltage
SCL,SDA
SDA,INT1,
INT2
SDA,INT1,
INT2
SCL,SDA
VIL
Input low voltage
SCL,SDA
-
-
-
0.2VDD
V
INT1
VOUT = 0.4V
1.0
1.6
-
mA
6
10
-
mA
6
10
-
mA
IOL1
Output low current 1
IOL2
Output low current 2
INT2
SDA
VOUT = 0.4V
2015-12-0001
PT0280-8
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12/11/15
PT7C43390/43390C
Real-time Clock Module
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AC Electrical Characteristics
Measure conditions
Input pulse voltage
VIH = 0.9 × VDD, VIL = 0.1 × VDD
Input pulse rise/fall time
20ns
Output determination voltage
VOH = 0.5 × VDD, VOL = 0.5 ×VDD
Output load
100pF + pull-up resistance 1kΩ
Symbol
Parameter
VDD > 1.35 V*2
VDD > 3.0 V*2
Min.
Typ.
Max.
Min.
Typ.
Max.
Unit
FSCL
SCL clock frequency
0
-
100
0
-
400
kHz
tLOW
SCL clock low time
4.7
-
-
1.3
-
-
µs
tHIGH
SCL clock high time
4
-
-
0.6
-
-
µs
SDA output delay time
-
-
3.5
-
-
0.9
µs
tPD
tSU.STA
Start condition setup time
4.7
-
-
0.6
-
-
µs
tHD.STA
Start condition hold time
4
-
-
0.6
-
-
µs
tSU.DAT
Data input setup time
250
-
-
100
-
-
ns
tHD.DAT
Data output hold time
0
-
-
0
-
-
µs
tSU.STO
Stop condition setup time
4.7
-
-
0.6
-
-
µs
tR
SCL, SDA rise time
-
-
1
-
-
0.3
µs
tF
SCL, SDA fall time
-
-
0.3
-
-
0.3
µs
4.7
-
-
1.3
-
-
µs
tBUF
Bus release time
tI
Noise suppression time
100
50
ns
*1. Since the output format of the SDA pin is Nch open-drain output, output data definition 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 Operating Conditions”.
2015-12-0001
PT0280-8
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12/11/15
PT7C43390/43390C
Real-time Clock Module
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Recommended Layout for Crystal (for PT7C43390)
Built-in Capacitors Specifications and Recommended External Capacitors
Parameter
Build in capacitors
Recommended External capacitors for crystal
CL=12.5pF
Recommended External capacitors for crystal
CL=6pF
Symbol
Typ.
Unit
XIN to GND
CG
5
pF
XOUT to GND
CD
5
pF
XIN to GND
C1
18
pF
XOUT to GND
C2
18
pF
XIN to GND
C1
7
pF
XOUT to GND
C2
7
pF
Note: The frequency of crystal can be optimized by external capacitor C1 and C2, for frequency=32.768 kHz, C1 and C2 should
meet the equation as below: Cpar + [(C1+CG)*(C2+CD)]/ [(C1+CG) + (C2+CD)] =CL
Cpar is all parasitical capacitor between X1 and X2.
CL is crystal’s load capacitance.
Crystal Specifications
Parameter
Symbol
Min.
Typ.
Max.
Unit
fO
-
32.768
-
kHz
Serial resistance
ESR
-
-
70
kΩ
Load capacitance
CL
-
6/12.5
-
pF
Nominal frequency
2015-12-0001
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12/11/15
PT7C43390/43390C
Real-time Clock Module
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Functional Description
1. Overview of Functions
1.1. Clock function
CPU can read or write data including the year (last two digits), month, date, day, hour, minute, and second. Any (two-digit) year
that is a multiple of 4 is treated as a leap year and calculated automatically as such until the year 2099.
1.2. Alarm function
This device has two alarm system (Alarm 1 and Alarm 2) that outputs interrupt signals from INT1 pin or INT2 pin to CPU when
the date, day of the week, hour, minute or second correspond to the setting. Each of them may output interrupt signal separately at
a specified time. The alarm may be selectable between on and off for matching alarm or repeating alarm.
1.3. Programmable square wave output
For PT7C43390, square wave output at pin 1or pin 5. Six frequencies are selectable: 1, 2, 4, 8, 16, 32768 Hz.
1.4. Interface with CPU
PT7C43390: I2C bus interface.
1.5. Calibration function
With the calibration bits properly set, the accuracy can be improved to better than ±2 ppm at 25°C.
2. Configuration of Data Communication
2.1. Data Communication
For data communication, the master device in the system generates a start condition for the IC. Next, the master devices transmits
4-bit device code “0110”, 3-bit command and 1-bit read / write command to the SDA line. 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 IC. The master device
generates an acknowledgment signal for every 1-byte. Regarding details refer to "I2C-bus Serial Interface".
Read/Write bit
Acknowledgment bit
Start condition
Device Code
STA
0
1
1
Command
0
C2
C1
C0
R/W
ACK
Stop condition
1-byte data
B7
B6
B5
B4
B3
B2
2015-12-0001
B1
B0
ACK
PT0280-8
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STP
12/11/15
PT7C43390/43390C
Real-time Clock Module
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2.2. Configuration of Command
8 types of command are available for the RTC. The RTC reads / writes the various registers by inputting these fixed codes and
commands. The RTC does not perform any operation with any codes and commands other than those below. However, in case that
the fixed codes or the commands are failed to be recognized in the 1st byte but are successfully recognized in the 2nd and higher
bytes, the commands are executed.
*1. Write only flag. The PT7C43390 initializes by writing "1" in this register.
*2. Scratch bit. This is a register which is available for read / write operations and can be used by users freely.
*3. Read only flag. Valid only when use the alarm function. When the alarm time matches, this flag is set to "1", and it is cleared
to "0" when reading.
*4. Read only flag. "POC" is set to "1" when power is applied. It is cleared to "0" when reading. Regarding "BLD", refer to "Low
Power Supply Voltage Detection Circuit".
*5. Test bit. Be sure to set "0" in use.
*6. No effect when writing. It is "0" when reading.
3. Configuration of Registers
3.1. 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 accesses. In this case, transmit / receive the data of hour in B7, minute, second in B0, in 3-byte.
The RTC transfers a set of data of time to the real-time data register when it recognizes the read command.
Therefore, the RTC keeps precise time even if time-carry occurs during the read operation of real-time data register.
2015-12-0001
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PT7C43390/43390C
Real-time Clock Module
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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
Day of the week is counted in the order of 00, 01, 02, 03, 04, 05, 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 12-hour mode, write 0; AM, 1; PM in the AM / PM bit. In 24-hour mode, 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 mode): 11 p.m. (H1, H2, H4, H8, H10, H20, AM / PM, 0) = (1, 0, 0, 0, 1, 0, 1, 0)
Example (24-hour mode): 22 (H1, H2, H4, H8, H10, H20, AM / PM, 0) = (0, 1, 0, 0, 0, 1, 1, 0)
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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)
3.2. 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.
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 Voltage 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 interrupt function has come. The INT1 flag at alarm 1 interrupt mode and the INT2 flag at alarm 2 interrupt mode
are set to "1". Set "0" in INT1AE (B5 in the status register 2) or in INT2AE (B1 in the status register 2) after reading "1" in the
INT1 flag or in the INT2 flag. 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 mode. Set the flag ahead of write operation of the real-time data register in case of 24hour mode.
0: 12-hour mode
1: 24-hour mode
B7: RESET
The internal IC is initialized by setting this bit to "1". This bit is write-only. It is always "0" when reading. 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".
3.3. 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.
B7
B6
B5
B4
B3
B2
B1
B0
INT1FE
INT1ME
INT1AE
32kE
INT2FE
INT2ME
INT2AE
TEST
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W : Read/Write
B0: TEST
This is a test flag. 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 INT2 pin. Below Table shows how to select the mode. To use an alarm 2
interrupt, set alarm interrupt mode, then access the INT2 register.
Table: Output Modes for INT2 Pin
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*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 INT1 pin. Below Table shows how to select the mode. To use alarm 1
interrupt, access the INT1 register after setting the alarm interrupt mode.
Table: Output Modes for INT1 Pin
*1. Don't care (both of 0 and 1 are acceptable).
3.4. INT Register 1 and INT Register 2
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 interrupts by status register 2; these
registers work as alarm-time data registers. If selecting the output of user-set frequency by status register 2; these registers work as
data registers to set the frequency for clock output. From each INT1 and INT2 pin, a clock pulse and alarm interrupt are output.
a. 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 mode that they set by using the status register 1.
INT Register 1 and INT Register 2 (Alarm-Time Data)
The INT register 1 has A1WE, A1HE, and 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, and A2mE in the
INT register 2.
Setting example: alarm time "7:00 pm" in the INT register 1
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(1) 12-hour mode (status register 1 B6 = 0)
Set up 7:00 PM
Data written to INT register 1
_(*1)
_(*1)
_(*1)
_(*1)
_(*1)
_(*1)
_(*1)
0
Hour
1
1
1
0
0
0
1
1
Minute
0
0
0
0
0
0
0
1
Day of the Week
B7
B0
*1. Don't care (both of 0 and 1 are acceptable).
(2) 24-hour mode (status register 1 B6 = 1)
Set up 19:00 PM
Data written to INT register 1
_(*1)
_(*1)
_(*1)
_(*1)
_(*1)
_(*1)
_(*1)
0
Hour
1
0
0
1
1
0
1(*2)
1
Minute
0
0
0
0
0
0
0
1
Day of the Week
B7
B0
*1. Don't care (both of 0 and 1 are acceptable).
*2. Set up AM / PM flag along with the time setting.
b. INT Register 1 and INT Register 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.
B7
B6
B5
B4
B3
B2
B1
B0
1Hz
2Hz
4Hz
8Hz
16Hz
SC2
SC3
SC4
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W : Read/Write
INT Register 1 (Data Register for Output Frequency)
B7
B6
B5
B4
B3
B2
B1
B0
1Hz
2Hz
4Hz
8Hz
16Hz
SC5
SC6
SC7
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W : Read/Write
INT Register 2 (Data Register for Output Frequency)
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Example of Output from INT1 and INT2 Registers (Data Register for Output Frequency)
3.5. 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".
B7
B6
B5
B4
B3
B2
B1
B0
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
3.6. Free Register
This free register is a 1-byte SRAM type register that can be set freely by users.
B7
B6
B5
B4
B3
B2
B1
B0
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
4. Power-on Detection Circuit and Register Status
The power-on detection circuit operates by power-on the RTC, as a result each register is cleared; each register is set as follows.
Real-time data register: 00 (Y), 01 (M), 01 (D), 0 (day of the week), 00 (H), 00 (M), 00 (S)
Status register 1: "01h"
Status register 2: "80h"
INT register 1: "80h"
INT register 2: "00h"
Clock correction register: "00h"
Free register: "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 INT 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".)
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For the regular operation of power-on detection circuit, as seen in below Figure, the period to power-up the RTC 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 INT pin.
In this case, power-on the RTC once again because the internal data may be in the indefinite status.
Moreover, regarding the processing right after power-on, refer to "Flowchart of Initialization and Example of Real-time Data
Set-up".
*1. 0 V indicates that there are no potential differences between the VDD pin and VSS pin.
How to Raise the Power Supply Voltage
5. Register Status After Initialization
The status of each register after initialization is as follows.
Real-time data register: 00 (Y), 01 (M), 01 (D), 0 (day of the week), 00 (H), 00 (M), 00 (S)
Status register 1: "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 below Figure.)
Status register 2: "00h"
INT1 register: "00h"
INT2 register: "00h"
Clock correction register: "00h"
Free register: "00h"
 Status Register 1 Data at Initialization
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6. Low Power Supply Voltage Detection Circuit
The RTC 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. 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. After reading the BLD flag, the sampling operation is restarted. Without initializing, if the next
BLD flag reading 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.
Timing of Low Power Supply Voltage Detection Circuit
7. Circuits Power-on and Low Power Supply Voltage Detection
Below Figure shows the changes of the POC flag and BLD flag due to VDD fluctuation.
POC Flag and BLD Flag
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8. Nonexistent Data and End-of-Month
When users write the real-time data, the RTC checks it. In case that the data is invalid, the RTC does the following procedures.
 Processing of nonexistent data
*1. In 12-hour mode, 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 of reading, 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 in 1 second, after writing.
At this point the carry pulse is sent to the minute-counter.
 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.
9. Alarm and Interrupt Output
9.1. INT1 Pin and INT2 Pin Output Mode
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, minuteperiodical interrupt output 2 and 32.768 kHz Output are also selectable. To switch the output mode, use the status register 2. Refer
to "Status register 2" in "Configuration of Registers". 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.
a. 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 and minute in the INT1 / INT2 register. Refer to "INT1 register and INT2
register" in "Configuration of Registers".
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a) Alarm setting of "W (day of the week), H (hour), m (minute)"
*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.
Alarm Interrupt Output Timing
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b) Alarm setting of "H (hour)"
*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.
Alarm Interrupt Output Timing
b. 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.
c. Per-minute edge interrupt output
Per-minute edge interrupt output is the function to output "L" from the INT1 / INT2 pin, when the first minute-carry 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
INT1 pin output mode, input "0" in INT1ME in the status register 2. In the INT2 pin output mode, input "0" in INT2ME.
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*1. Pin output is set to "H" by disabling the output mode within 7.81 ms, because the signal of this procedure is maintained for
7.81 ms. Note that pin output is set to "L" by setting enable the output mode again.
Timing of Per-Minute Edge Interrupt Output
d. Minute-periodical interrupt output 1
The minute-periodical interrupt 1 is the function to output the one-minute clock pulse (Duty 50%) from the INT1 / INT2 pin, when
the first minute-carry processing is done, after selecting the output mode.
*1. Setting the output mode disable makes the pin output "H", while the outputs from the INT1 / INT2 pin is in "L". Note that pin
output is set to "L" by setting enable the output mode again.
Timing of Per-Minute Steady Interrupt Output 1
e. 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 7.81 ms, from the INT1 pin, synchronizing with the
first minute-carry processing after selecting the output mode. However, during reading in the real-time data register, the procedure
delays at 0.5 seconds max. Thus output "L" from the INT1 pin also delays at 0.5 seconds max. During writing in the real-time data
register, some delay is made in the output period due to write timing and the second-data during writing.
(1) During normal operation
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(2) During reading in the real-time data register
(3) During writing in the real-time data register
Timing of Minute-periodical Interrupt Output 2
f. Operation of power-on detection circuit (only in the INT1 pin output mode)
When power is applied to the RTC, 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 INT1 pin.
9.2. Alarm 1 Function and INT2 Pin Output Mode
In the output mode for INT2 pin, users are able to select the output; alarm 2 interrupt, user-set frequency, per-minute edge
interrupt, minute-periodical interrupt. To switch the output mode for INT2 pin and the alarm 1 function, use the status register 2.
Refer to "Status register 2" in "Configuration of Registers". When switching the output mode for INT2 pin, be careful of the
output status of the pin. Especially, when using alarm 2 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.
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a. 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 reading, the INT2 flag is once cleared automatically. In the alarm 1 function, the INT1 flag (B3 in the status register 1) is set to
"H" when the set time has come. The INT1 flag is also cleared once by reading. 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.
1) Alarm setting of "W (day of the week), H (hour), m (minute)"
*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.
Alarm Interrupt Output Timing
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2) Alarm setting of "H (hour)"
*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.
Alarm Interrupt Output Timing
b. 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 "INT1 register and INT2 register" in "Configuration of
Registers".
Output Timing of User-set Frequency
c. Per-minute edge interrupt output
Per-minute edge interrupt output is the function to output "L" from the INT2 pin, when the first minute-carry processing is done,
after selecting the output mode. To set the pin output to "H", in the INT2 pin output mode, input "0" in INT2ME in the status
register 2 in order to turn off this mode.
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*1. Pin output is set to "H" by disabling the output mode within 7.81 ms, because the signal of this procedure is maintained for
7.81 ms. Note that pin output is set to "L" by setting enable the output mode again.
Timing of Per-minute Edge Interrupt Output
d. Minute-periodical interrupt output 1
The minute-periodical interrupt 1 is the function to output the one-minute clock pulse (Duty 50%) from the INT2 pin, when the
first minute-carry processing is done, after selecting the output mode.
*1. Setting the output mode disable makes the pin output "H", while the output from the INT2 pin is in "L".
Note that pin output is set to "L" by setting enable the output mode again.
Timing of Minute-periodical Interrupt Output 1
10. 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 RTC 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 (
data,
refer to "15.2. How to calculate". When not using this function, be sure to set "00h".
Function to Clock Correction
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10.1. Setting values for registers and correction values
Setting Values for Registers and Correction Values (Minimum Resolution: 3.052 ppm (B0 = 0))
Setting Values for Registers and Correction Values (Minimum Resolution: 1.017 ppm (B0 = 1))
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10.2. How to calculate
a. If current oscillation frequency > target frequency (in case the clock is fast)
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 "Calculation example 1".
*2. Measurement value when 1 Hz clock pulse is output from the INT pin.
*3. Target value of average frequency when the clock correction function is used.
*4. Refer to "Function to Clock Correction".
 Calculation example 1
In case of current oscillation frequency actual measurement value = 1.000070 [Hz], target oscillation frequency = 1.000000 [Hz],
B0 = 0 (Minimum resolution = 3.052 ppm)
Convert the correction value "106" to 7-bit binary and obtain "1101010b".
Reverse the correction value "1101010b" and set it to B7 to B1 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)
b. If current oscillation frequency < target frequency (in case the clock is fast)
Caution The figure range which can be corrected is that the calculated value is from 0 to 62.
 Calculation example 2
In case of current oscillation frequency actual measurement value = 0.999920 [Hz], target oscillation frequency = 1.000000 [Hz].
B0 = 0 (Minimum resolution = 3.052 ppm)
Thus, set the clock correction register:
(B7, B6, B5, B4, B3, B2, B1, B0) = (1, 1, 0, 1, 1, 0, 0, 0)
 Calculation example 3
In case of current oscillation frequency actual measurement value = 0.999920 [Hz], target oscillation frequency = 1.000000 [Hz],
B0 = 1 (Minimum resolution = 1.017 ppm)
This calculated value exceeds the correctable range 0 to 62.
B0 = "1" (minimum resolution = 1.017 ppm) indicates the correction is impossible.
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10.3. How to confirm a setting value for a register and the result of correction
This RTC does not adjust the frequency of the crystal oscillation by using the function of clock correction. Therefore users cannot
confirm if it is corrected or not by measuring output 32.768 kHz. When the function of clock correction is being used, the cycle of
1 Hz clock pulse output from the INT pin changes once in 20 times or 60 times, as shown in below figure.
Confirmation of the clock correction
Measure a and b by using the frequency counter*1. Calculate the average frequency (Tave) based on the measurement results.
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
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.
11. Serial Interface
11.1. I2C-bus Serial Interface
a. 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.
b. 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
PT7C43390 gets standby.
Start / Stop Conditions
c. 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
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acknowledgment signal back. For example, as seen in below Figure, in case that the PT7C43390 is the device working for
receiving data and the master device is the one working for sending data; when the 8th clock pulse falls, the master device releases
the SDA line. After that, the PT7C43390 sends an acknowledgment signal back, and set the SDA line to "L" at the 9th clock pulse.
The PT7C43390 does not output an acknowledgment signal is that the access is not being done regularly.
Output Timing of Acknowledgment Signal
 Data reading in the PT7C43390
After detecting a start condition, the PT7C43390 receives device code and command. The PT7C43390 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 PT7C43390 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 reading. Next, input a stop condition to the
PT7C43390 to finish access.
Example of Data Reading 1 (1-Byte Data Register)
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Example of Data Reading 2 (3-Byte Data Register)
 Data writing in the PT7C43390
After detecting a start condition, the PT7C43390 receives device code and command. The PT7C43390 enters the write-data mode
by the read / write bit "0". Input data from B7 to B0 in 1-byte. The PT7C43390 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 PT7C43390 to finish access.
Example of Data Writing 1 (1-Byte Data Register)
Example of Data Reading 2 (3-Byte Data Register)
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d. Data access
 Real-time data 1 access
*1. Set NO_ACK = 1 when reading.
*2. Transmit ACK = 0 from the master device to the RTC when reading.
Real-Time Data 1 Access
 Real-time data 2 access
*1. Set NO_ACK = 1 when reading.
*2. Transmit ACK = 0 from the master device to the RTC when reading.
Real-Time Data 2 Access
 Status register 1 access and status register 2 access
*1. 0: Status register 1 selected, 1: Status register 2 selected
*2. Set NO_ACK = 1 when reading.
Status Register 1 Access and Status Register 2 Access
 INT1 register access and INT2 register access
In reading / writing 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 "INT1 register and INT2 register" in "Configuration of
Registers".
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Caution: Users cannot use both functions of alarm 1 interrupt and output of user-set frequency for the INT1 pin and INT2
pin simultaneously.
*1. 0: INT1 register selected, 1: INT2 register selected
*2. Set NO_ACK = 1 when reading.
*3. Transmit ACK = 0 from the master device to the RTC when reading.
INT1 Register Access and INT2 Register Access
*1. 0: INT1 register selected, 1: INT2 register selected
*2. Set NO_ACK = 1 when reading.
INT1 Register and INT2 Register (Data Register for Output Frequency) Access
 Clock correction register access
*1. Set NO_ACK = 1 when reading.
Clock Correction Register Access
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 Free register access
*1. Set NO_ACK = 1 when reading.
Free Register Access
12. Reset After Communication Interruption
In case of communication interruption in the PT7C43390, for example, during communication the power supply voltage drops so
that only the master device is reset; the PT7C43390 does not operate the next procedure because the internal circuit keeps the state
prior to communication interruption. The PT7C43390 does not have a reset pin so that users usually reset its internal circuit by
inputting a stop condition. If the SDA is outputting "L" (during output of acknowledgment signal or reading), the PT7C43390
does not accept a stop condition from the master device. In this case, users are necessary to finish acknowledgment output or
reading of the SDA. Below Figure shows how to reset. First, input a start condition from the master device (the PT7C43390
cannot detect a start condition because the SDA in the PT7C43390 is outputting "L"). Next, input a clock pulse equivalent to 7byte data access (63-clock) from the SCL. During this, release the SDA line for the master device. By this procedure, SDA I/O
before communication interruption is finished, so that the SDA line in the PT7C43390 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.
Figure How to Reset
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13. Flowchart of Initialization and Example of Real-time Data Set-up
*1. Do not communicate for 0.5 seconds since the power-on detection circuit is in operation.
*2. Reading the real-time data 1 should be completed within 1 second after setting the real-time data 1.
Example of Initialization Flowchart
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14. Examples of Application Circuits
Caution: Start communication under stable condition after power-on the power supply in the system.
Caution: The above connection diagrams do not guarantee operation. Set the constants after performing sufficient evaluation using
the actual application.
Examples of Application Circuits for PT7C43390
Mechanical Information
TSSOP-8L
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SOIC-8L
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TDFN2x3-8L
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TDFN4.0x4.0-8L
Ordering Information
Part No.
Package Code
Package
PT7C43390LE
L
Lead free and Green 8-pin TSSOP
PT7C43390LEX
L
Lead free and Green 8-pin TSSOP Tape/Reel
PT7C43390WE
W
Lead free and Green 8-pin SOIC
PT7C43390WEX
W
Lead free and Green 8-pin SOIC Tape/Reel
PT7C43390ZEE
ZE
Lead free and Green 8-pin TDFN2x3
PT7C43390CZEE
ZE
Lead free and Green 8-pin TDFN4x4
Note:

E = Pb-free and Green

Adding X Suffix= Tape/Reel
Pericom Semiconductor Corporation  1-800-435-2336  www.pericom.com
Pericom reserves the right to make changes to its products or specifications at any time, without notice, in order to improve design or performance and to supply
the best possible product. Pericom does not assume any responsibility for use of any circuitry described other than the circuitry embodied in Pericom product. The
company makes no representations that circuitry described herein is free from patent infringement or other rights of Pericom.
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