PWM Generation Issue

[M_Sukumar]

Hi team,

Can you help for resolve the below PWM generation issue,

we are using STM32H7A3ZIT6 controller, in that for the PWM generation configured Advanced Timer 1 with the below configuration and we are getting the PWM wave like below pic. But we need exact square wave PWM. 

can you please help to resolve this issue, and can you suggest what kind of parameter we need to configure?

we configure presale value as 63:

       

we configure presale value as 1: 

    

Note :-

But we need set clock cycle a 20ms,

[Andrew Neil]

Are you sure your scope probes are properly compensated?

https://resources.pcb.cadence.com/blog/what-is-oscilloscope-probe-compensation 

https://www.rohde-schwarz.com/uk/products/test-and-measurement/essentials-test-equipment/digital-oscilloscopes/understanding-probe-compensation_254520.html

https://www.youtube.com/watch?v=5IqqJVIHmN8 

You'll also need to show your schematic - what is the external circuitry on the PWM output pin?

BTW: Your scope must have a screenshot facility - that would give far clearer results than photographs!

[TDK]

Your scope settings show the channel is AC coupled. Set it to DC coupled instead.

The PWM signal is most likely just fine.

[Billy OWEN]

Hi @M_Sukumar 

The forum moderator had marked your post as needing a little more investigation and direct support. An online support case has been created on your behalf, please stand by for just a moment and you will hear from us.

Regards,

Billy