Help implementing SNES Controller + PIC1F887

[mackrackit]

I have not used one of those controllers..
The internal OSC should be accurate enough, the speed might be the issue.
You are pushing buttons while data is being sent to the display or looping for the next call???

Would be nice to push the data from the controller instead of calling for it. Is there some way to have a signal going to a PORTB interrupt?

[Daguava]

Oh wow, I feel so stupid, but I've just solved my own problem. Undervolting the shift-register inside of the controller by a half volt was enough to cause it to freak out giving me incomplete output, my code now works as expected and everything is working great.

Thanks for the help, and, if you wouldn't mind, could you elaborate a bit on what you meant by the PortB interrupt, I've done very little with interrupts and don't quite get what you mean.

[mackrackit]

Glad it is working.

PORTB has an interrupt on change. When the state of PORTB.0 changes an interrupt can be triggered.

An example would be counting parts on a conveyor. The MCU can be off doing something else like sending data to a display while a sensor/switch is activated as a part passes by. Then when the MCU is finished with the display the part count can be increases.
That is using PBP interrupts. If you go with ASM or Darrel Taylor's instant interrupts then the trigger is instantly. But you still need a certain amount of time for everything to happen.

Either way, you do not need to loop back and check the state of the pin, it happens for you in the background.