Can the same timer realize two independent PWM pulses?

bigbat

Can the same timer realize two independent PWM pulses? [Copy link]

Currently, I want to use one timer to achieve two PWM outputs. The two PWM outputs have the same period, different phases (and can be adjusted), and the same pulse width. It is best to have PWM outputs with different pulse widths. The microcontroller used is GD32F103C8T6.

I would like to ask an expert whether it is possible to use the same timer but different channels to achieve two PWM outputs.

wangerxian

It is actually difficult to achieve different phases. My idea is to start the PWM output at different times to achieve different phases, but the phase difference is definitely inaccurate.

sint27

I also want to know more about this aspect. The motor control of the massager seems to be like this. I wonder if it requires specific MCU support.

秦天qintian0303

The question is, is your phase adjustable and precise?

bigbat

wangerxian posted on 2022-7-22 15:28 It is actually difficult to achieve different phases. My idea is to turn on the PWM output at different times to achieve different phases, but this phase difference is definitely not accurate...

I have a few ideas, that is, when starting the first PWM, start the timer, and start the second PWM in the timer interrupt. My problem is that I need three timers. The timer in my board also has a pulse capture function, which also requires two timers. So I want to ask if PWM with the same period can use one timer, so as to save a timer. Otherwise, I need to replace the chip with more timers.

wangerxian

bigbat posted on 2022-7-23 08:57 I don't have much ideas. When starting the first PWM, start the timer, and start the second PWM in the timer interrupt. My problem is that I need to...

There is another way, which is to use a timer to generate the interrupt with the maximum resolution of the desired PWM, and then both PWMs are controlled in the timer interrupt. However, there are disadvantages, that is, the accuracy will be poor, and sometimes the interrupt priority will be preempted by other interrupts.

吾妻思萌

Is it possible to divide the reference crystal frequency?

bigbat

Azuma Simeng published on 2022-7-24 16:18 Is it possible to divide the frequency of the reference crystal oscillator?

This has nothing to do with the crystal oscillator. I am just asking if it is possible to use one timer to generate two PWMs and save one timer. This project can be realized by using three timers. But I only want to use two.

huo_hu

If software is involved, anything can be done, but the target cannot be high.

Only one of the phase and duty cycle can be changed. If both are changed together, the period must be different.

waterssj

Some chips can add a delay period, and a timer can output several channels