Notes On Using 8-Bit Timer/Event Counters 00 And 01; Start Timing Of 8-Bit Timer Counter; Timing Of External Event Counter Operation - NEC switch User Manual

6.5 Notes on Using 8-Bit Timer/Event Counters 00 and 01

(1) Error on starting timer
An error of up to 1 clock occurs after the timer is started until a match signal is generated. This is because 8-bit
timer counters 00 and 01 (TM00 and TM01) are started asynchronously to the count pulse.
Count pulse
TM00, TM01 count value
(2) Setting of 8-bit compare register
8-bit compare registers 00 and 01 (CR00 and CR01) can be set to 00H.
Therefore, one pulse can be counted when the 8-bit timer/event counter operates as an event counter.
TI00, TI01 input
CR00, CR01
TM00, TM01 count value
Interrupt request flag
90
CHAPTER 6 8-BIT TIMER/EVENT COUNTERS 00 AND 01
Figure 6-10. Start Timing of 8-Bit Timer Counter
00H
Timer starts
Figure 6-11. Timing of External Event Counter Operation
User's Manual U12978EJ3V0UD
01H 02H
00H
00H 00H
03H 04H
00H 00H