UPD78F9500MA-CAC-A Datasheet, PDF (143/342 Pages) Renesas Technology Corp – 8-Bit Single-Chip Microcontrollers

CHAPTER 7 8-BIT TIMER H1
<4> When 8-bit timer counter H1 and the CMP11 register match, TOH1 output becomes inactive and the
compare register to be compared with 8-bit timer counter H1 is changed from the CMP11 register to the
CMP01 register. At this time, 8-bit timer counter H1 is not cleared and the INTTMH1 signal is not
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 TMHE1 = 0.
If the setting value of the CMP01 register is N, the setting value of the CMP11 register is M, and the count clock
frequency is fCNT, the PWM pulse output cycle and duty are as follows.
PWM pulse output cycle = (N+1)/fCNT
Duty = Active width : Total width of PWM = (M + 1) : (N + 1)
Cautions 1. In PWM output mode, the setting value for the CMP11 register can be changed during timer
count operation. However, three operation clocks (signal selected using the CKS12 to
CKS10 bits of the TMHMD1 register) or more are required to transfer the register value after
rewriting the CMP11 register value.
2. Be sure to set the CMP11 register when starting the timer count operation (TMHE1 = 1) after
the timer count operation was stopped (TMHE1 = 0) (be sure to set again even if setting the
same value to the CMP11 register).
(2) Timing chart
The operation timing in PWM output mode is shown below.
Caution Make sure that the CMP11 register setting value (M) and CMP01 register setting value (N) are
within the following range.
00H ≤ CMP11 (M) < CMP01 (N) ≤ FFH
User’s Manual U18172EJ3V0UD
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