Increase the execution speed for PIC16f877a

anupama619 · Joined: 10 Sep 2009 Posts: 47

Hey all,
I am using PIC16F877A and a crystal of value 20MHz. I want to increase the execution speed. Can I use a crystal greater than 20MHz ?

Guest · Posted: Wed Feb 10, 2010 8:09 am

While it is possible to -try- to use a faster xtal, it may not work, or may be erratic.

Instead, you can either use a newer, faster pin compatible PIC.
or
Rewrite your code to trim out bad code, delays, long jump tables, use int math instead of fp math, build your own libraries, use asm code if smaller than C, etc.

SherpaDoug · Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA

First look at the PIC data sheet. Is this a commercial product, or a home experiment? If it is a product or if failure could be life threatening etc. then stick with what is on the data sheet, or get a written waiver from Microchip.

If it is a home project, give it a try! Be aware it may not work over all voltages or temperatures. But if it is a cat toy, who cares if it croaks in the icebox.

Also, tell us how you make out. How fast can a PIC16F877A REALLY go?
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The search for better is endless. Instead simply find very good and get the job done.

Rohit de Sa · Joined: 09 Nov 2007 Posts: 282 Location: India

Overclocking a PIC haha :-D I myself have pushed a PIC16F628A to 25MHz. :-)

I read this ( http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=54 ) a long while back. Have fun!

Rohit

arunb · Joined: 08 Sep 2003 Posts: 492 Location: India

Use a 18F4620 its pin compatible, faster with max. speed at 40 Mhz, has more RAM and ROM.

If your application needs a smaller pin count, consider using a 18F2620, has the same max. speed as the 4620 but has smaller pin count at 28 pins.

Hope this was helpful..

thanks
arunb

Gabriel · Joined: 03 Aug 2009 Posts: 1067 Location: Panama

I read a while ago some guy ran a 16F84 up to 32MHz without any issues... exept a bit of heat and more power comsumption.... but that was expected.... as one of the previous posters said... if its for a home experiment, you should try it.

Your timing routines will need tuning though... and baud rates too.
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