Push Button Help

[elmurry]

Hi everyone,
I'm newby in uC and need some help.
I use pic16f877a to generate PWM and I have written the code to generate it with 50 kHz freq. and 50% duty, but now I want to use two push buttons conneted to RE0 and RE1 pins to change the duty cycle, one for up and the other for down the duty. how to configure the ports and what code lines should I add to achieve this task ?

Thanks

[Mike Walne]

You will need something similar to keypad reading.

CCS provides a sample.

Look up button debounce on the forum.

You will also need to deal with over-flow and under-flow.

Do you want auto-repeat?

This is not a write it for you forum.

Cut some code yourself. When (if) you get stuck ask for help and guidance.

Mike

[hoangkhuong]

As far as I know, you can do that by configuring pin E0 and E1 as input pin. Then use function like input(PIN_E0) to check whether it is pushed or not.

[Mike Walne]

I'm assuming that you know how to connect the ports to switches.

When you close a switch, yes indeed input(pin_x) returns the port state. Don't forget to set port as digital.

You will also have to deal with switch bounce and how quickly you want the duty rate to increase / decrease.

CCS provides loads of sample code. Have a play with some, get to know the ropes.

Mike

[PCM programmer]

Here's an example of servo motor control with push-buttons that might
help you with the basic structure of the program and with the push-button
code:
http://www.ccsinfo.com/forum/viewtopic.php?t=47510