Interrupt Handlers and Variable Scope

[kaszeta]

I'm trying to implement a shaft encoder which simply triggers an interrupt handler and increments a variable every time the encoder creates a pulse.

The code mostly works, in that the interrupt handler is called when the pulse on Digital Input 1 occurs, it then checks the value of digital input 10 for the B phase, and increments and decrements a counter as appropriate.

The interrupt handler is getting called, since I can put debugging printf()'s in there which show +'s and -'s every time the handler is called.

The problem is that the global variable I'm using isn't ever incremented or decremented, like a scope problem.

I've read the C18 manual about interrupt handlers, and thought I had everything taken care of:

I've already got a
#pragma interruptlow interrupt_handler_low save=section(".tmpdata)

And I've tried
#pragma interruptlow interrupt_handler_low save=variablename

but neither of these help. Ideas?

(I'd post the exact code, but it's over with the bot without an internet connection. Perhaps later this evening).