The Industrial Raspberry Pi Forum

Hello Team,

I am using Revolution Pi Connect+ and DIO module. when trying to generate a PWM output by configuring in the pictory, the maximum frequency is 400 Hz. I need it for a higher frequency of around 1-2 kHz. is it possible to change in the pictory? And also I need to read PWM input from a function generator. is it possible, if yes how?
Please help!

Thanks and Regards,
Nithinkumar Mirle Prasannakumar

Hi Nithinkumar, unfortunately 400 Hz is the highest available PWM frequency. Please have in mind that at 400 Hz the resolution of the PWM is handled in 10% steps.

Hello Dirk,

Thanks for your reply. I have the below questions.

1. can you please explain what exactly 10% steps mean?
2. Can Rev Pi read PWM input?

Hi nithinkumar,
Have a look here How to Configure Digital I/O Modules
Especially the "OutputPWMFrequency" parameter:

This is where, for all outputs that are to be operated in PWM mode, the frequency at which the PWM signal is to be generated is specified. In general, the higher the frequency, the higher the step size in which the clock ratio can be set.

There is also a nice viddo tutorial available Tutorial 15 – PWM am RevPi DIO

Hello Dirk,

Thanks for your input.
Can we generate hardware PWM? if yes which are all the i/o pins enabled?

Thanks and Regards
Nihinkumar

Hi Nihinkumar, the GPIOs of the DIO are switched using the PiBridge. So you do the PiCtory configuration of an output to use PWM. Then you save and reset the driver. Then you can apply the PWM value to the output channel i.e. by using "piTest -w O_1,10" i.e. 10% on/90% off.