How to capture PWM signal

[shma103]

capture pwm

Hi,

Anybody knows how to write a code for PIC microcontroller that can read/capture pwm signal and give output according to the pwm ?

The pwm signal is coming from a sensor. I want to program the PIC microcontroller to read this pwm signal and will give the output to other circuitry based on the pwm signal.

any ideas or links that can help me ?

thanks.

 

[bobcat1]

capture pwm signal

Hi

In order to do that you must use a timer\counter module in the microcontroller

measure the Ton and the Toff

Set a timer to inc every 5 Usec and trigger it from the signal raise edge and shut it down when the signal fall - look at the register of the counter and you have your time priod measurement.

If you can switch to MSP430 Ti supply a code in assembly & C language

All the best


Bobi

 

[Cyrix-Cracker]

capture pwm pic

Yes You can use microcntroller in capturing PWM signals trough a sensors.
You can just use a built in timer or a pre program code and compare it to a signal occuring in the input

or to suggest you better use a PSoC Cypress Basic Stamp USB dongle.
"
amplifiers, ADCs, DACs, filters and comparators and digital functions such as timers, counters, PWMs, SPI and UARTs. "

so what are you waiting for..PSoC CY8C27xxx device

https://www.cypress.com

Thanks

Cyrix-Cracker

 

[idlebrain]

pic capture pwm

You can better measure a PWM signal with capture/compare feature of a Timer.

For this

1. The signal is to be connected to a pin (associated with a timer) which can generate a capture interrupt.
2. Enable capture on both edges (raising, falling)
3. With this you can easily measure OnTime and OffTimeof PWM.

You can find so many appnoted in the net

 

[VVV]

capturing pwm signals

The easiest way is to use a PIC that has a CCP module. Otherwise, it can still be done, but with a lot more work.
Here is appnote AN545 fom Microchip, which describes how to measure duty-cycle. www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011090

 

[shma103]

pwm capture msp430

Thanks all for the advice.

at this moment I'm looking at PIC microcontroller solutions since the projects involve several other modules that use this microcontroller. I'll try the other options after the PIC.

Thanks VVV for the link.

shma