8-Bit Timer/Event Counter Operations; 8-Bit Timer/Event Counter Mode - NEC mPD780208 Subseries User Manual

7.4 8-Bit Timer/Event Counter Operations

7.4.1 8-bit timer/event counter mode

(1) Interval timer operations
The 8-bit timer/event counter operates as an interval timer that generates interrupt requests repeatedly
at intervals of the count value preset to the 8-bit compare registers (CR10 and CR20).
When the count values of 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 interrupt request signals (INTTM1
and INTTM2) are generated.
The count clock of TM1 can be selected using bits 0 to 3 (TCL10 to TCL13) of timer clock select register
1 (TCL1). The count clock of TM2 can be selected using bits 4 to 7 (TCL14 to TCL17) of timer clock select
register 1 (TCL1).
For the operation when the value of the compare register is changed during timer count operation, refer
to 7.5 8-Bit Timer/Event Counter Operating Precautions (3).
t
Count clock
TM1 count value 00
Count start
CR10
INTTM1
TO1
Remark Interval time = (N + 1) x t: N = 00H to FFH
158
CHAPTER 7 8-BIT TIMER/EVENT COUNTER
Figure 7-8. Interval Timer Operation Timing
01 N 00
Clear
N N
Interrupt request acknowledgment
Interval time
User's Manual U11302EJ4V0UM
01 N 00
Clear
N
Interrupt request acknowledgment
Interval time
01 N
N
Interval time