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holy
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| timer0 in INT_EXT |
 Posted: Sun Oct 31, 2004 7:11 pm |
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I use timer0 and int_ext
why in my int_ext interrupt timer0 interrupt is disabled? |
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Haplo
Joined: 06 Sep 2003
Posts: 659
Location: Sydney, Australia
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| Posted: Sun Oct 31, 2004 7:16 pm |
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What PIC are you using?
In PIC16s you can not have interrupts inside other interrupts. The first thing the interrupt dispatcher does is to diable all the interrupts before entering the ISR.
Quoting from PIC16F877 datasheet:
| Quote: | When an interrupt is responded to, the GIE bit is
cleared to disable any further interrupt, the return
address is pushed onto the stack and the PC is loaded
with 0004h. |
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holy
Guest
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| Posted: Mon Nov 01, 2004 9:17 am |
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I use PIC18F4320
INT_RTCC (function1) 10ms
INT_EXT ( call delay 1s, when delay 1s need to function1
Can I do So? |
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Haplo
Joined: 06 Sep 2003
Posts: 659
Location: Sydney, Australia
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| Posted: Mon Nov 01, 2004 3:58 pm |
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You'd have to make the RTCC interrupt high priority by using the keyword 'fast'. From the manual:
| Quote: | #INT_xxxx fast
The keyword FAST may be used with the PCH compiler to mark an interrupt high priority. A fast interrupt can interrupt another interrupt handler. The compiler does no save/restore in a fast ISR. You should do as little as possible and save any registers that need to be saved on your own. |
By the way, avoid using delays in ISRs. |
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