Just a quick one about the 819

[2camjohn]

I read something in the datasheet and I realised I may not be understanding the way the PIC wakes from sleep properly.


Accoring to my interpretation of the datasheet if you wake the PIC with INTCON.GIE disabled the program continues from where it was (ie the next instruction after the sleep instruction.
If you wake the PIC from sleep with the INTCON.GIE enabled it runs the interrupt routine.

Is that correct?

Thanks guys, sorry I know I suck at reading datasheets.
John

 

[eblc1388]

If you wake the PIC from sleep with the INTCON.GIE enabled it runs the interrupt routine. Is that correct?

95%. The datasheet said that it first execute the next instruction after "SLEEP" instruction, then branch to interrupt routine.

 

[2camjohn]

Thanks alot L.Chung.

95% thats a personal best for me :lol:

 

[Matt(Pic progger)]

Hello,

As far as I can remeber, the pic fetches the instruction AFTER sleep BEFORE it goes to sleep.

Soooo this means that when the PIC wakes up, it will already have the next instruction in it's registers ready to run, this can sometimes be a pain, so to get round this problem, make the instruction after sleep NOP, this means that when the PIC wakes up it will do nothing, then either run the INT sub (intcon,gie enabled) or your code (intcon,gie disabled).

I hope this helps!