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CHAPTER 8 16-BIT TIMER/EVENT COUNTER
User’s Manual U12697EJ3V0UM
8.5 Cautions
(1) Error on starting timer
An error of up to 1 clock occurs before the match signal is generated after the timer has been started. This is
because 16-bit timer counter 0 (TM0) is started asynchronously in respect to the count pulse.
Figure 8-29. Start Timing of 16-Bit Timer Counter 0
TM0 count value
0000H
0001H
0002H
0004H
Count pulse
Timer starts
0003H
(2) 16-bit compare register settings
Set any value other than 0000H in 16-bit capture/compare registers 00 and 01 (CR00, 01).
Single pulse counts are consequently not possible for the usage time, used as an event counter.
(3) Operation after changing compare register during timer count operation
If the value to which the current value of 16-bit capture/compare register 00 (CR00) has been changed is less
than the value of 16-bit timer counter 0 (TM0), TM0 continues counting, overflows, and starts counting again from
0. If the new value of CR00 (M) is less than the old value (N), the timer must be restarted after the value of
CR00 has been changed.
Figure 8-30. Timing After Changing Compare Register During Timer Count Operation
CR00
N
M
Count pulse
TM0 count value
X – 1
X
FFFFH
0000H
0001H
0002H
Remark
N > X > M
