NEC 78K0 User Manual page 190

<4> When 8-bit timer counter Hn and the CMP1n register match, TOHn output becomes inactive and the
compare register to be compared with 8-bit timer counter Hn is changed from the CMP1n register to the
CMP0n register.
generated.
<5> By performing procedures <3> and <4> repeatedly, a pulse with an arbitrary duty can be obtained.
<6> To stop the count operation, set TMHEn = 0.
If the setting value of the CMP0n register is N, the setting value of the CMP1n register is M, and the count clock
frequency is f , the PWM pulse output cycle and duty are as follows.
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PWM pulse output cycle = (N+1)/f
Duty = Active width : Total width of PWM = (M + 1) : (N + 1)
Cautions 1. In PWM output mode, three operation clocks (signal selected using the CKSn2 to CKSn0
bits of the TMHMDn register) are required to transfer the CMP1n register value after
rewriting the register.
2. Be sure to set the CMP1n register when starting the timer count operation (TMHEn = 1) after
the timer count operation was stopped (TMHEn = 0) (be sure to set again even if setting the
same value to the CMP1n register).
190
CHAPTER 8 8-BIT TIMERS H0 AND H1
At this time, 8-bit timer counter Hn is not cleared and the INTTMHn signal is not
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User's Manual U16227EJ2V0UD