PIC with Automatic Context Saving

[Bruce]

FYI: BCF IOCAF,IOCAF1 in your int handler is probably not doing what you think. IOCAF is in bank 7 on the 16F1828, and PBP resets the bank to 1 when you use ASM. It's up to you to make sure you're in the correct register bank in your .asm routines.

[Dick Ivers]

Bruce, Thanks for the info re. IOCAF bank switching in the handler. Actually, I don't think I need that line of code anyway. As stated in the header, the test program is for one-time use only. The circuit works correctly as is.

Hank, With two interrupt sources you would first go to the handler identified after DEFINE INTHAND. Once there, set up a test to determine which interrupt occurred by polling the interrupt flags. Then carry out the appropriate interrupt action. I have never done this, so maybe Bruce or Darrel could help with a better explanation.

[mister_e]

Hint: BTFSS or BTFSC, or BIT?GOTO

;************************************************* ***************
;* BIT?GOTO : Macro - Bit test and Long Goto *
;* *
;* Input : Cstate = constant desired state for goto *
;* Regin = register *
;* Bitin = bit *
;* Label *
;* Output : None *
;* *
;* Notes : Preserves C, Z, handles page boundaries, resets bank.*
;************************************************* ***************

[Dick Ivers]

16F1828 now working with two interrupt sources.
BTFSS works well as a source selection tool ... thanks Steve.
Automatic context saving feature of the chip working.
End of story.