Invert PWM- signal 18f46k80

-Terppa- · Joined: 08 Jan 2018 Posts: 59 Location: Finland

Hello all PIC gurus!

I have fast question. Is that chip(18f46k80) any hardware support to invert PWM- signal? Or is it only change to use hardware (transistors,ICs,Etc)?

keypoints in code:

temtronic · Posted: Thu Jan 21, 2021 6:30 am

fast answer
OK, I didin't look ,but
if you take the opposite PWM value, that's 'inversion' ?

say PWM is on 70%, off 30%...inversion would be on 30%,off 70% .

Ttelmah · Joined: 11 Mar 2010 Posts: 19222

Your chip has two different types of module to generate PWM outputs.
The CCP modules, and an ECCP module.
The CCP does not offer any way to invert the output, except as Jay says
to just reverse the number used. So for a given required duty cycle:

set_pwm1_duty(1023-cycle);

The ECCP module, supports active low or active high outputs, so setup
for a single PWM, and select active low, and you have the inverted signal.

There is only one ECCP module on your chip though.

Remember the ECCP, can simultaneously generate complementary
signals, with a dead band delay between them.

-Terppa- · Joined: 08 Jan 2018 Posts: 59 Location: Finland

Thank you Mr temtronic and Mr Ttelmah