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GD32E23x User Manual
336
Output PWM function
In the output PWM mode
(by setting the CHxCOMCTL bits to 3’b110 (PWM mode0) or to 3’b
111(PWM mode1), the channel can generate PWM waveform according to the
TIMERx_CAR registers and TIMERx_CHxCV registers.
The period is determined by TIMERx_CAR and duty cycle is determined by TIMERx_CHxCV.
Figure 14-52. PWM mode timechart
shows the PWM output mode and interrupts
waveform.
If TIMERx_CHxCV is greater than TIMERx_CAR, the output will be always active under
PWM mode0 (CHxCOMCTL==3’b110).
And if TIMERx_CHxCV is equal to zero, the output will be always inactive under PWM
mode0 (CHxCOMCTL==3’b110).
Figure 14-52. PWM mode timechart
0
CHxVAL
CAR
PWM MODE0
PWM MODE1
Cx OUT
Cx OUT
Interrupt signal
CHxIF
CHxOF
Channel output prepare signal
As is shown in
Figure 14-50. Channel output compare principle
, when TIMERx is
configured in compare match output mode,a middle signal which is OxCPRE signal (Channel
x output prepare signal) will be generated before the channel outputs signal. The OxCPRE
signal type is defined by configuring the CHxCOMCTL bit. The OxCPRE signal has several
types of output function. These include keeping the original level by configuring the
CHxCOMCTL field to 0x00, setting to high by configuring the CHxCOMCTL field to 0x01,
setting to low by configuring the CHxCOMCTL field to 0x02 or toggling signal by configuring
the CHxCOMCTL field to 0x03 when the counter value matches the content of the
TIMERx_CHxCV register.
The PWM mode 0/PWM mode 1 output is another output type of OxCPRE which is setup by
configuring the CHxCOMCTL field to 0x06/0x07. In these modes, the OxCPRE signal level is
changed according to the counting direction and the relationship between the counter value