PIC running way too slow ? | Piclist

A discussion group for the PICMicro microcontroller. Also called the Microchip PIC, this list is dedicated to the use and abuse of this fine, simple, microcontroller. Close to topic posts are welcome, ie. general electronics.

I have a PIC18F452 with a 20mhz crystal. I setup timer0 interrupt with a DIV multiplier of 256 20,000,000/4/256/256 = 76 interrputs per second. I flip the state of a led each interrupt. from the led blink rate I can see that the interrupt is called once every 3 seconds or so. Like, What the **** ? Is my pic running 100 times slower than it should ? My delay functions are working perfectly. Anyone can think of a good way to test if the pic is running at the correct speed , without a scope ? (speaking of scopes, I've seen some software scopes for the PC, are they any good ?) Help. Thanks, Shachar Weis.

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Powering that LED 76 times a second should just give the appearence of always being on, maybe somewhat dim. I am sure you know that, maybe you have your oscillator setup wrong? or perhaps (well not likely but) a long initialization and then your WDT is resetting the uC

Charles

-----Original Message-----
From: holopoint.rm [mailto:h...@rocketmail.com]
Sent: Tuesday, July 29, 2003 12:20 AM
To: p...@yahoogroups.com
Subject: [piclist] PIC running way too slow ?

I have a PIC18F452 with a 20mhz crystal. I setup timer0 interrupt with a DIV multiplier of 256 20,000,000/4/256/256 = 76 interrputs per second. I flip the state of a led each interrupt. from the led blink rate I can see that the interrupt is called once every 3 seconds or so. Like, What the **** ? Is my pic running 100 times slower than it should ? My delay functions are working perfectly. Anyone can think of a good way to test if the pic is running at the correct speed , without a scope ? (speaking of scopes, I've seen some software scopes for the PC, are they any good ?) Help. Thanks, Shachar Weis.

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Discussion Groups | Piclist | PIC running way too slow ?

PIC running way too slow ? - holopoint.rm - Jul 29 1:19:00 2003

RE: PIC running way too slow ? - Charles Douvier - Jul 29 10:05:00 2003