delayus()

Graham Webb · Joined: 18 Apr 2008 Posts: 9

I am using a PIC16F876A with a 20MHz oscillator and trying to get a controllable pulse with using the delayus() function.

dyeatman · Joined: 06 Sep 2003 Posts: 1923 Location: Norman, OK

What version are you using?

Note this from the CCS manual:

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

For earlier versions of the compiler that don't support 16-bit variables
as the parameters in delay_us and delay_ms, see this thread:
http://www.ccsinfo.com/forum/viewtopic.php?t=32288

rnielsen · Joined: 23 Sep 2003 Posts: 852 Location: Utah

There are a couple of draw backs in using delays in your code. First, everything stops while your code waits for the delay to end. Your processor is just setting there with nothing to do until the delay is done. Second, if you happen to have any interrupts firing away like your serial ISR or any other timer/counter/external interrupt these could lengthen the original delay command.

I would suggest using a timer to control your delay. This way your program isn't 'hung' while they delay times out. Timers can be very precise too. Just a thought.

Ronald
Why can't mosquitos suck fat instead of blood?

Graham Webb · Joined: 18 Apr 2008 Posts: 9

Thanks all. I believe it was an issue with the version number. I resorted to putting a 1us delay in a for loop, but all my printf statements stopped working with the for loop in play, so I will try the timers.