RBport on change interrupt problem

Guest · Posted: Fri Jan 20, 2006 4:47 pm

When I enable the interrupt and put the pic to sleep, it wake up and enter to the ISR before I push a key. Is there something I have to do before enable the port interrupt? I'm using the ICD debugger (with port b internal pull ups): is this the problem?

I have 16F876 PIC, 3.19 compiler version, 3.43 IDE version.

P.S: sorry for my bad english.

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

You must read the port before you enable the interrupt.
This will clear the latch that detects the "change condition".
Then it will be setup to detect the next keypress.

JohnLeung · Joined: 18 May 2004 Posts: 15

Try putting a small delay to "debounce" after wake up to avoid any noisy problem for RB on-change port, even though you have pull-up for PORTB.