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CHAPTER 6 16-BIT TIMER/EVENT COUNTER 0
User’s Manual U15798EJ2V0UD
6.6 16-Bit Timer/Event Counter 0 Cautions
(1) Timer start errors
An error of up to one clock may occur in the time required for a match signal to be generated after timer start.
This is because 16-bit timer counter 0 (TM0) is started asynchronously to the count clock.
Figure 6-28. Start Timing of 16-Bit Timer Counter 0 (TM0)
TM0 count value
0000H
0001H
0002H
0004H
Count clock
Timer start
0003H
(2) 16-bit timer compare register setting (in the clear & start mode on match between TM0 and CR00)
Set 16-bit timer capture/compare registers 00, 01 (CR00, CR01) to other than 0000H. This means a 1-pulse
count operation cannot be performed when the timer is used as an event counter.
(3) Operation after compare register change during timer count operation
If the value after 16-bit timer capture/compare register 00 (CR00) is changed is smaller than that of 16-bit timer
counter 0 (TM0), TM0 continues counting, overflows and then restarts counting from 0. Thus, if the value (M)
after CR00 has changed is smaller than that (N) before the change, it is necessary to reset and restart the timer
after changing CR00.
Figure 6-29. Timing After Change of Compare Register During Timer Count Operation
CR00
N
M
Count clock
TM0 count value
X – 1
X
FFFFH
0000H
0001H
0002H
Remark
N > X > M
Содержание mPD780344 Series
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