CHAPTER 7 8-BIT TIMER 80
User’s Manual U16898EJ3V0UD
128
7.5 Notes on 8-Bit Timer 80
(1) Error when timer starts
The time from starting the timer to generation of the match signal includes an error of up to 1.5 clocks. This is
because, if the timer is started while the count clock is high, the rising edge may be immediately detected and
the counter may be incremented (refer to
Figure 7-6
).
Figure 7-6. Case Where Error of 1.5 Clocks (Max.) Occurs
8-bit timer counter 80
(TM80)
Count pulse
Clear signal
Selected clock
TCE80
Delay A
Delay B
Selected clock
TCE80
Clear signal
Count pulse
TM80 count value
00H
01H
02H
03H
...
Delay A
Delay B
If the timer is started when the selected clock is high
and if delay A > delay B, an error of up to 1.5 clocks occurs.
(2) Setting of 8-bit compare register 80
8-bit compare register 80 (CR80) can be set to 00H.
(3) Note on setting STOP mode
Before executing the STOP instruction, be sure to stop the timer operation (TCE80 = 0).