
CHAPTER 9 8-BIT TIMERS H0 AND H1
User’s Manual U17260EJ6V0UD
286
Figure 9-12. Operation Timing in PWM Output Mode (4/4)
(e) Operation by changing CMP1n (CMP1n = 02H
→ 03H, CMP0n = A5H)
Count clock
8-bit timer
counter Hn
CMP01
TMHE1
INTTMH1
TOH1
(TOLEV1 = 0)
00H 01H 02H
A5H 00H 01H 02H 03H
A5H 00H
<1>
<4>
<3>
<2>
CMP11
<6>
<5>
02H
A5H
03H
02H (03H)
<2>’
80H
<1>
The count operation is enabled by setting TMHEn = 1. Start the 8-bit timer counter Hn by masking one count
clock to count up. At this time, PWM output outputs an inactive level.
<2>
The CMP1n register value can be changed during timer counter operation. This operation is asynchronous
to the count clock.
<3>
When the values of the 8-bit timer counter Hn and the CMP0n register match, the value of the 8-bit timer
counter Hn is cleared, an active level is output, and the INTTMHn signal is output.
<4>
If the CMP1n register value is changed, the value is latched and not transferred to the register. When the
values of the 8-bit timer counter Hn and the CMP1n register before the change match, the value is
transferred to the CMP1n register and the CMP1n register value is changed (<2>’).
However, three count clocks or more are required from when the CMP1n register value is changed to when
the value is transferred to the register. If a match signal is generated within three count clocks, the changed
value cannot be transferred to the register.
<5>
When the values of the 8-bit timer counter Hn and the CMP1n register after the change match, an inactive
level is output. The 8-bit timer counter Hn is not cleared and the INTTMHn signal is not generated.
<6>
Clearing the TMHEn bit to 0 during timer Hn operation sets the INTTMHn signal to the default and PWM
output to an inactive level.
Remark
n = 0, 1
<R>