PIC16F630, no inputs RA0 and RA1?

Question

I'm trying to use RA0 and RA1 as inputs, but I can't get it to work.

They work fine as outputs, no problem. They go high-z when programmed as inputs. As input I have a pullup and switch to ground. I also have a problem turning on the weak pullups on RA0 and RA1 - can't get it to work.

The others, RA2, RA4, RA6 work fine as inputs. I can turn on the weak pullups, no problem. Tried an other 16F630, same picture.

Is there a flaw in the 16F630 or its datasheet? Or something I have overlooked?

Spehro Pefhany · Accepted Answer

Perhaps too obvious, but have you set up CMCON correctly? Best regards, Spehro Pefhany-- "it's the network..."                          "The Journey is the reward"             Info for manufacturers:  software/hardware/analog  Info for designers:

Grog · Answer

Turn off the comparator.  CMCON register.Page 39.  6.2.HTHsGtG

Frank Bemelman · Answer

"Spehro Pefhany"  schreef in berichtnews:Bingo! I came across CMCON earlier today, but never gave it atry - it's not very obvious from the PORT A0,A1 'schematic' thatCMCON has an effect on using A0,A1 as digital inputs.Thanks a lot ;)-- Thanks, Frank.(remove 'x' and 'invalid' when replying by email)

Frank Bemelman · Answer

"Grog"  schreef in berichtnews:D%A2d.33989$That did the trick. I'll never forget now ;)-- Thanks, Frank.(remove 'x' and 'invalid' when replying by email)

Spehro Pefhany · Answer

No problem. PICs generally power up with any port pins that *can* beanalog inputs in analog mode (ADC or comparator). Best regards, Spehro Pefhany-- "it's the network..."                          "The Journey is the reward"             Info for manufacturers:  software/hardware/analog  Info for designers:

PIC16F630, no inputs RA0 and RA1?

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