Real time clock module
Epson Toyocom
Built-in EEPROM and Unique ID-ROM
I2C-Bus INTERFACE REAL TIME CLOCK MODULE
RX - 8731 LC
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Built in frequency adjusted 32.768 kHz crystal unit.
Interface Type
:
:
:
:
I2C-Bus interface (400 kHz)
1.7 V to 5.5 V
Operating voltage range
Wide Timekeeper voltage range
Low backup current
1.3 V to 5.5 V
0.35
C-MOS output With Control Pin
The various functions include full calendar, alarm, timer.
µA / 3 V (Typ.)
Actual size
32.768 kHz frequency output function
:
* The I2C-Bus is a trademark of NXP Semiconductors
Block diagram
Overview
32.768 kHz
• Built in EEPROM and ID-ROM
• Built in 10 Byte ( 80 bit) EEPROM
• Built in 6 Byte ( 48 bit ) ID-ROM
DIVIDER
OSC
CLOCK
and
CALENDAR
FOE
• Programmable I/O ports
FOUT
CONTROLLER
• 4 Programmable I/O ports
FOUT
TIMER REGISTER
ALARM REGISTER
INTERRUPTS
CONTROLLER
• Interface Type
/ IRQ
• I2C-Bus high-speed bus specifications. (400 kHz)
4
• 32.768 kHz frequency output function
• FOUT pin output (C-MOS output), CL=30 pF
• FOE pin enables output on/off control.
• Output frequency is selectable.
I/O Port
P00 – P03
CONTROL
REGISTER
A 0
I2C-Bus
and
< 32.768 kHz, 1024 Hz, 1 Hz >
INTERFACE
CIRCUIT
SDA
SYSTEM
CONTROLLER
• The various interrupt function
• Alarm interrupt function
SCL
• Timer interrupt function
• Update interrupt function
EEPROM
10 Byte ( 80 bit )
ID-ROM
6 Byte ( 48 bit )
Pin Function
Terminal connection /External dimensions
(Unit:mm)
Signal Name Input / Output
Function
RX − 8731 LC
SCL
SDA
Input
Serial Clock input pin.
1. FOE
2. P00
3. SDA
4. SCL
5. A 0
12. VDD
Bi-directional Data input and output pin.
A 0
Input
Device address A0 input pin.
11. P01
10. P02
9. P03
FOUT pin is 32.768 kHz clock output pin ( C-MOS ) that output control is
possible.
FOE pin control the frequency output from FOUT pin with FSEL1-bit and
FSEL0-bit.
FOUT
Output
FOE
Input
2.4
/ IRQ
Output
Interrupt output pin. ( N-ch open drain )
8. / IRQ
7. FOUT
P00
P01
P02
P03
6. GND
2.8
Bi-directional Programmable I/O ports.
VSOJ − 12pin
V
DD
Connected to a positive power supply.
Connected to a ground.
GND
Specifications (characteristics)
Refer to application manual for details.
!
Recommended Operating Conditions
!
Current consumption characteristics
Ta = −40 °C to +70 °C
Item
Symbol
Condition
Min.
Typ.
Max.
Unit
Item
Symbol
Condition
Min. Typ. Max. Unit
DD
Power voltage
Clock voltage
Operating
V
V
1.7
1.3
3.0
3.0
5.5
5.5
V
V
CLK
DD
V
SCL
f
= 0 Hz
/ IRQ = OFF
= 5 V
0.45 0.9
µA
OPR
°
T
-40
+25
+85
C
temperature
BK
I
DD
V
FOUT : output OFF
( Hi - z )
!
Frequency characteristics
= 3 V
0.35 0.7
Item
Symbol
Condition
Rating
Unit
Current
Consumption
DD
V
a
°
C
T
V
= +25
Frequency
tolerance
−6
10
SCL
f
= 0 Hz
∆
±
*
×
f / f
5
23
= 5 V
8.0 16.0
µA
DD
= 3.0 V
/ IRQ = OFF
a
°
T
V
T
= +25
C
32k
I
1 Max.
3 Max.
s
FOUT :
32.768 kHz output
CL = 30 pF
DD
DD
V
Oscillation
Start-up time
= 1.6 V
STA
t
a
°
°
C
= 3 V
5.0 10.0
= -40 C to +85
s
DD
V
= 1.6 V
*Equivalent to 1 minute of monthly deviation
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