16F1823 - Can't get RA3 (MCLR) to be a switch input (attached switch resets PIC).

[HankMcSpank]

See REGISTER 4-1:CONFIGURATION WORD 1 in the datasheet.

If LVP = 1 the /MCLR bit is ignored and the pin remains the reset input. Since you didn't include CONFIG2 settings in your code, LVP defaulted to 1 ON and that caused the problem.

I would get rid of the 10mS pause in the int handler, then test & clear whatever IOCAF flag bits are set to determine which switch was pressed. This is a really nice feature on the 16F1s since IOC pins have individual flag bits now. I.E. you don't need to read the port when the IOC happens any more.

Thanks Bruce ....that 10ms pause has now gone (I can't recall why it was in there...obviously been dabbling at one point & it's remained!)

Re testing for an IOCAF flag (to establish which switch has been pressed)...is there a win over vs checking for a 'Low'/0V as I'm doing presently? (if so, then I'll work out what needs to be done....but all the new registers on this IC are scrambling my head!)