RE5 pin on PIC18F6720

[Guest]

I was using pin RA1 as a digital I/O to monitor a button being pressed. Each time the button was pressed it was reconized by the processor. I switched the monitoring from RA1 to RE5 and configured Port E with RE5 as an input. Now when the buton is pressed, it does not always respond. The button may have to be pressed a number of times before it is reconized by the processor. I connected a scope to RE5 and the signal is there each time the key is pressed. I reconnected it back to RA1 and it works fine. It acts as if the RA5 is not active all the time.

Does Port E require some special setup configuration? I noticed in the data sheet that Port E is multiplexed with CCP. I turned off CCP in my code and it still responds the same way.

Any ideas would be appreicated.

[newguy]

This may explain it?

http://www.ccsinfo.com/forum/viewtopic.php?t=23622&highlight=porte

Hope this helps.

[Ttelmah]

Question. How high/low is the signal going?.
PortE, has Schmidt trigger inputs, which means that the signal has to get above 0.8Vdd, to be seen as a 'high'. The portA pins, only need the signal to reach 0.25Vdd+0.8v to be seen as 'high'.

Best Wishes

[Guest]

Thanks for the help. The problem was the signal voltage is right on the edge.