GD32VF103 User Manual
237
Figure 15-15. Output-compare in three modes
CEN
CNT_REG
00
01
02
03
04
05
…
.
62
63
Overflow
match toggle
CNT_CLK
OxCPRE
00
01
02
03
04
05
…
.
62
63
01
02
03
04
05
…
.
00
match set
match clear
OxCPRE
OxCPRE
PWM mode
In the PWM output mode (by setting the CHxCOMCTL bit to 3
’
b110 (PWM mode 0) or to 3
’
b
111(PWM mode 1)), the channel can generate PWM waveform according to the
TIMERx_CAR registers and TIMERx_CHxCV registers.
Based on the counter mode, PWM can also be divided into EAPWM (Edge-aligned PWM)
and CAPWM (Center-aligned PWM).
The EAPWM
’
s period is determined by TIMERx_CAR and the duty cycle is determined
by TIMERx_CHxCV.
Figure 15-16. Timing chart of EAPWM
shows the EAPWM output and
interrupts waveform.
The CAPWM
’
s period is determined by 2*TIMERx_CAR, the duty cycle is determined by
2*TIMERx_CHxCV.
Figure 15-17. Timing chart of CAPWM
interrupts waveform.
In up counting mode, if the value of TIMERx_CHxCV is greater than the value of
TIMERx_CAR, the output will be always inactive in PWM mode 0 (CHxCOMCTL=3
’
b110).
And if the value of TIMERx_CHxCV is greater than the value of TIMERx_CAR, the output will
be always active in PWM mode 1 (CHxCOMCTL=3
’
b111).