PIC Overclocking

Hello to all,

I am still confused to the fact that a PIC can be Overclocked without any problem.

I mean to say run it at 20Mhz with a 4 Mhz PIC.

Is that true?

any info on Overclocking available ?

regards

Hello Charudatt,

C>>I am still confused to the fact that a PIC can be Overclocked without any problem.

I mean to say run it at 20Mhz with a 4 Mhz PIC.

Is that true?<<

I device (a PIC chip in this case) is guaranteed by the manufacture to run up to a certain point. You can push (overclock) these chips to some degree, but there is no guarantee they will preform above the manufacturers specifications. Most will preform above the manufactures specifications...but the faster you go, the more heat you generate, and the closer you come to exceeding the chips limits... thus reliability problems will start to crop up.

Dwayne

Hi, Charudatt

We had an interesting chat about that on RC Groups / DIY section

I Did it : a 4 Mhz can run at 20 Mhz ; I read about 4 Mhz running at 8 in Germany ( serious info !!! ) ....Yess BUT

remember chips are statistically tested; 4Mhz are very certainly 20 Mhz chips not running correctly for the entire temp. scale or else.


If there are defective parts in the test pack, the whole pack is "low speed stamped"

That's all ...

This is a good trick for hobbyists ...but professionnals can't do seriously that, as results are not garanteed.

Alain

More infos about Microcontroller OverClocking:

http://www.dvanhorn.org/Micros/All/Overclocking.php


Best regards,


Luciano

Every single microcontroller is tested many times
during fabrication.

The low speed test is performed first.
(Example of low speed test = 4MHz + security margins).

If there is a huge demand for 4MHz microcontrollers
no further higher speed test is performed.
The microcontrollers are shipped as 4MHz parts.

Luciano


* * * * * * *

Microchip handbook URL:

http://ww1.microchip.com/downloads/e...Doc/00169C.pdf

See page 14, Manufacturing Process.

I like Alian's point of view and always read something like that here and there.

I have not tried it but now I can test it myself.

I always wondered why did Microchip make two versions of the same chip , they could just do away with one version, unless they wanted to make some fast bucks by selling faster chips.

Earlier we used to get 16F877 - 20 but now somehow we do not find that any more in the market.

Thank you folks for inputing your ideas and research on the topic.

regards
Charudatt

Hi, Charudatt

" I like Alian's point of view ..."

Many Thanks to you , but I'd like to raise very high one point on this forum ...

I'm not an Alien ... or I don't know it !!!

Thanks for offering that joke ...

I pointed out that / 20 devices are now called / i ...
But I didn't see /i Devices in MPLAB ...

Best regards

Alain

Sorry on the goof up with the name.

Second thing I noticed with the Microchip chips is that the print is very faint.

Is there any reason to this or this is normal. Very difficult to read it with a normal eye :)

regards

Hi, charudatt

never apologise ... I really laughed from that !!! This is one of the favourite frenchies games : humour !!!

You're right : reading is less and less easy ... for that I use a magnifier lens and look at markings under a put aside light source.

Seems only pro's have to deal with such chips : look at recent chips ... It's difficult to find anything else than SMD

Regards

Alain

Charduatt
There was already a thread with exactly the same subject.

See:

http://www.picbasic.co.uk/forum/show...t=overclocking

Before starting a new thread you should do a search on the forum

regards

Ralph