External Event Counter Operation - NEC PD78081(A) User Manual

6.4.2 External event counter operation

The external event counter counts the number of external clock pulses to be input to the TI5/PI00/TO5 and TI6/
P101/TO6 pins with 8-bit timer registers 5 and 6 (TM5 and TM6).
TM5 and TM6 are incremented each time the valid edge specified with the timer clock select register 5 and 6 (TCL5
and TCL6) is input. Either the rising or falling edge can be selected.
When the TM5 and TM6 counted values match the values of 8-bit compare registers 50 and 60 (CR50 and CR60),
TM5 and TM6 are cleared to 0 and the interrupt request signals (INTTM5 and INTTM6) are generated.
Figure 6-10. 8-Bit Timer Mode Control Register Setting for External Event Counter Operation
TCEn TMCn6
1 0
TMCn
Remarks 1. n = 5, 6
2. : don't care
Figure 6-11. External Event Counter Operation Timings (with Rising Edge Specification)
Count Clock
TMn Count Value
CRn0
TCEn
INTTMn
Remarks 1. N = 00H to FFH
2. n = 5, 6
CHAPTER 6 8-BIT TIMER/EVENT COUNTERS 5 AND 6
LVSn LVRn TMCn1 TOEn
0 0
00 01 02 03
0
TOn output disable
Clear and start mode on match of TMn and CRn0
TMn operation enable
04 05 N-1
N
N 00 01 02 03
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