
RX
-
8025
SA
/
NB
Page - 1
ETM10E-04
I
2
C-Bus Interface Real-time Clock Module
RX
-
8025
SA
/
NB
•
Features built-in 32.768-kHz quartz oscillator, frequency adjusted for high precision
(
±
5
×
10
−
6
when Ta = +25
°
C )
•
Supports I
2
C-Bus's high speed mode (400 kHz)
•
Includes time (H/M/S) and calendar (YR/MO/DATE/DAY) counter functions (BCD code)
•
Select between 12-hr and 24-hr clock mode.
•
Auto calculation of leap years until 2099
•
Built-in high-precision clock precision control logic
•
CPU interrupt generation function (cycle time range: 1 month to 0.5 seconds, includes interrupt flags
and interrupt stop function)
•
Dual alarm functions (Alarm_W: Day/Hour/Min, Alarm_D: Hour/Min)
•
32.768-kHz clock output (CMOS output with control pin)
•
Oscillation stop detection function (used to determine presence of internal data)
•
Power supply voltage monitoring function (with selectable detection threshold)
•
Wide clock (retention) voltage range: 1.15 V to 5.5 V
•
Wide interface voltage range: 1.7 V to 5.5 V
•
Low current consumption: 0.48
µ
A/3.0 V (Typ.)
1. Overview
This module is an I
2
C bus interface-compliant real-time clock which includes a 32.768-kHz quartz oscillator
that has been adjusted for high precision. In addition to providing a function for generating six types of
interrupts, a dual alarm function, an oscillation stop detection function (used to determine presence of valid
internal data at power-on), and a power supply voltage monitoring function, this module includes a digital clock
precision adjustment function that can be used to set various levels of precision.
Since the internal oscillation circuit is driven at a constant voltage, 32.768-kHz clock output is stable and free
of voltage fluctuation effects.
This implementation of multiple functions in one SMT package is ideal for applications ranging from cellular
phones to PDAs and other small electronic devices.
2. Block Diagram
OSC
OSC
Detect
/ INTA
SCL
SDA
FOUT
FOE
32 kHz
Output
Control
Divider
Correc
-tion
Div.
Interrupt Control
/ INTB
Shift Register
Time Counter
( Sec,Min,Hour,Day,Date,Month,Year )
Address
Decoder
Address
Register
Comparator_D
Comparator_W
Alarm_W Register
( Min,Hour,Day)
I/O
Control
Alarm_D Register
( Min,Hour )
Voltage
Detect
GND
V
DD