CHAPTER 9 8-BIT TIMERS 30 AND 40
User’s Manual U14826EJ5V0UD
116
9.5 Notes on Using 8-Bit Timers 30, 40
(1) Error on starting timer
An error of up to 1.5 clocks is included in the time between the timer being started and a match signal being
generated. This is because the rising edge is detected and the counter is incremented if the timer is started
while the count clock is high (see
Figure 9-24
).
Figure 9-24. Case of Error Occurrence of up to 1.5 Clocks
8-bit timer counter n0
(TMn0)
Count
pulse
Clear signal
Selected clock
TCEn0
Delay A
Delay B
Selected clock
TCEn0
Clear signal
Count pulse
TMn0 counter value
00H
01H
02H
03H
Delay A
Delay B
An error of up to 1.5 clocks occurs if the timer is started
when the selected clock is high and delay A > delay B.
Remark
n = 3, 4
