8-Bit Timer/Event Counter Operations; 8-Bit Timer/Event Counter Mode - NEC 78014Y Series User Manual

9.4 8-Bit Timer/Event Counter Operations

9.4.1 8-bit timer/event counter mode

(1) Interval timer operations
The 8-bit timer/event counter operates as an interval timer which generates interrupt requests repeatedly at
intervals of the count value preset to 8-bit compare registers (CR10 and CR20).
When the count values of the 8-bit timer registers 1 and 2 (TM1 and TM2) match the values set to CR10 and
CR20, counting continues with the TM1 and TM2 values cleared to 0 and the interrupt request signals (INTTM1
and INTTM2) are generated.
Count clock of TM1 can be selected with bits 0 to 3 (TCL10 toTCL13) of the timer clock select register 1 (TCL1).
Count clock of TM2 can be selected with bits 4 to 7 (TCL14 toTCL17) of the timer clock select register 1 (TCL1).
For the operation after changing compare register value during timer count operation, refer to 9.5 Cautions on
8-Bit Timer/Event Counter (3).
Count Clock
TM1 Count Value
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CR10
INTTM1
TO1
Interval time = (N + 1) × t : N = 00H to FFH
Remark
212
CHAPTER 9 8-BIT TIMER/EVENT COUNTER
Figure 9-8. Interval Timer Operation Timings
t
00 01 N
Count Start
N
Interval Time
00 01 N
Clear
N
Interrupt Request
Acknowledge
Interval Time
00 01 N
Clear
N N
Interrupt Request
Acknowledge
Interval Time