upd78f0124m6gba1-8et Renesas Electronics Corporation., upd78f0124m6gba1-8et Datasheet - Page 218

• Manufacturer Part Number: upd78f0124m6gba1-8et
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

9.5 Cautions for Watch Timer
setting bits 0 (WTM0) and 1 (WTM1) of WTM to 1), the interval until the first interrupt request (INTWT) is generated
after the register is set does not exactly match the specification made with bit 3 (WTM3) of WTM. This is because
there is a delay up to one 11-bit prescaler output cycle until the 5-bit counter starts counting. Subsequently, however,
the INTWT signal is generated at the specified intervals.
INTWT is then generated every 0.5 seconds.
218
Figure 9-4. Example of Generation of Watch Timer Interrupt Request (INTWT) (When Interrupt Period = 0.5 s)
When operation of the watch timer and 5-bit counter is enabled by the watch timer mode control register (WTM) (by
It takes a maximum of 0.515625 seconds for the first INTWT to be generated (2
WTM0, WTM1
INTWT
CHAPTER 9 WATCH TIMER
0.515625 s
User’s Manual U16315EJ3V1UD
0.5 s
0.5 s
9
× 1/32768 = 0.015625 s longer).