Overview Of Timepiece Timer; Fig. 18.1 Block Diagram Of Timepiece Timer - Fujitsu MB90420/5 (A) Series Hardware Manual

This chapter explains the function and operation of the timepiece timer.

18.1 Overview of Timepiece Timer

The timepiece timer consists of
second/minute/hour data register, 1/2 clock divider, 21-bit prescaler, and second/minute/hour counter. The
specified timepiece timer operates on the precondition that the MCU oscillation frequency is 4 MHz. It
operates as a real-world timer to provide the real-world time information.
n Block diagram of timepiece timer
Figure 18.1 shows the block diagram for the timepiece timer.
Main oscillation clock
1/2 clock divider
UPDT ST
INTE0 INT0
TIMEPIECE TIMER
timepiece
Second counter Minute counter
CL
EN
LOAD CO
6 bits
Second/minute/hour register
INTE1 INT1

Fig. 18.1 Block Diagram of Timepiece Timer

timer control register,
21-bit prescaler
CO
EN
Sub-second
register
Hour counter
CO
6 bits 6 bits
INTE2 INT2 INTE3
18-3
sub-second data register,
OE
OE
WOT
CO
INT3
IRQ