Operation As Pwm Output - NEC mPD78F0730 Preliminary User's Manual

8.4.2 Operation as PWM output

In PWM output mode, a pulse with an arbitrary duty and arbitrary cycle can be output.
8-bit timer compare register 01 (CMP01) controls the cycle of timer output (TOH1). Rewriting the CMP01 register
during timer operation is prohibited.
8-bit timer compare register 11 (CMP11) controls the duty of timer output (TOH1). Rewriting the CMP11 register
during timer operation is possible.
The operation in PWM output mode is as follows.
The TOH1 output level is inverted and 8-bit timer counter H1 is cleared to 0 when 8-bit timer counter H1 and the
CMP01 register match after the timer count is started. The TOH1 output level is inverted when 8-bit timer counter H1
and the CMP11 register match.
Setting
<1> Set each register.
(i) Setting timer H mode register 1 (TMHMD1)
TMHE1
TMHMD1 0
(ii) Setting CMP01 register
• Compare value (N): Cycle setting
(iii) Setting CMP11 register
• Compare value (M): Duty setting
Remark 00H ≤ CMP11 (M) < CMP01 (N) ≤ FFH
<2> The count operation starts when TMHE1 = 1.
<3> The CMP01 register is the compare register that is to be compared first after counter operation is enabled.
When the values of 8-bit timer counter H1 and the CMP01 register match, 8-bit timer counter H1 is cleared,
an interrupt request signal (INTTMH1) is generated, and TOH1 output is inverted. At the same time, the
compare register to be compared with 8-bit timer counter H1 is changed from the CMP01 register to the
CMP11 register.
<4> When 8-bit timer counter H1 and the CMP11 register match, TOH1 output is inverted 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.
204
Downloaded from Elcodis.com electronic components distributor
CHAPTER 8 8-BIT TIMER H1
Figure 8-9. Register Setting in PWM Output Mode
CKS12 CKS11 CKS10 TMMD11
0/1 0/1 0/1
Preliminary User's Manual U19014EJ1V0UD
TMMD10 TOLEV1 TOEN1
1 0 0/1 1
Timer output enabled
Default setting of timer output level
PWM output mode selection
Count clock (f ) selection
CNT
Count operation stopped