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CHAPTER 8 8-BIT TIMER/EVENT COUNTERS 2 TM2 AND 3 TM3
8.4 8-Bit Timer/Event Counters 2 TM2 and 3 TM3 Operations
8.4.1 8-bit interval timer operation
The 8-bit timer/event counters operate as interval timers which generate interrupt requests repeatedly at intervals
of the count value preset to 8-bit compare register n (CRn).
When the count values of the 8-bit counter n (TMn) match the values set to CRn, counting continues with the TMn
values cleared to 0 and the interrupt request signal (INTTMn) is generated.
Count clock of the 8-bit timer register n (TMn) can be selected with the timer clock select register n (TCLn).
[Setting]
<1> Set the registers.
• TCLn:
Select count clock.
• CRn:
Compare value
• TMCn: Select clear and start mode by match of TMn and CRn.
(TMCn = 0000×××0B × = don't care)
<2> After TCEn = 1 is set, count operation starts.
<3> If the values of TMn and CRn match, the INTTMn is generated and TMn is cleared to 00H.
<4> INTTMn generates repeatedly at the same interval. Set TCEn to 0 to stop count operation.
Remark n = 2, 3
t
Count clock
TMn count value
00H
Start count
CRn
TCEn
INTTMn
TIOn
Remarks 1. Interval time = (N + 1) × t: N = 00H to FFH
2. n = 2, 3
128
Figure 8-7. Interval Timer Operation Timings (1/3)
(a) Basic operation
01H
N
00H
Clear
N
N
Interrupt received
Interval time
Preliminary User's Manual U14581EJ3V0UM00
01H
N
00H
Clear
N
Interrupt received
Interval time
01H
N
N
Interval time
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