MB90423G Datasheet, PDF (41/99 Pages) Fujitsu Component Limited. – 16-Bit Original Microcontroller

MB90420G/5G (A) Series
5. Real Time Clock Timer
The real time clock timer is composed of a real time clock timer control register, sub second data register, second/
minute/hour data registers, 1/2 clock divider, 21-bit prescaler and second/minute/hour counters. Because the
MCU oscillation frequency operates on a given real time clock timer operation, a 4 MHz frequency is assumed.
The real time clock timer operates as a real world timer and provides real world time information.
• Block diagram
Main oscillator clock
1/2 clock
divider
21-bit
prescaler ^CO
EN
OE ^OE
WOT
Sub second
register
UPDT ST
CI Second
EN counter
LOAD
CO
Minute
counter
CO
Hour
counter
CO
6-bit
6-bit
5-bit
Second/minute/hour register
INTE0 INT0
INTE1 INT1
INTE2 INT2
INT3 INT3
IRQ
41