CHAPTER 7 8-BIT TIMER
7.5 Notes on Using 8-Bit Timer
(1) Error on starting timer
An error of up to 1 clock is included in the time between the timer being started and a match signal being
generated. This is because 8-bit timer counter n0 (TMn0) is started asynchronously to the count pulse.
Figure 7-28. Start Timing of 8-Bit Timer Counter
Count pulse
TMn0
count value
00H
01H
02H
03H
04H
Timer start
Remark n = 5, 6
(2) Setting of 8-bit compare register n0
8-bit compare register n0 (CRn0) can be set to 00H.
Therefore, one pulse can be counted when the 8-bit timer operates as an event counter.
Figure 7-29. Timing of Operation as External Event Counter (8-Bit Resolution)
TMI60 input
CR60
00H
00H
00H
00H
00H
TM60
count value
Interrupt request flag
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User’s Manual U15075EJ1V0UM00
NEC [ NEC ]
