Floating 1.34V on RA3 of PIC16F684

[Steve311]

Hello All; I am working with a PIC16F684 and for some reason, Pin RA4/AN3/T1G/OSC2/CLKOUT seems to ALWAYS show a floating 1.3V. Regardless of how I set the pin in the program, high or low, it still stays this way ALL THE TIME.

I am using the internal 31kHz oscilliator. Does this have anything to do with it? Or has anyone seen a similiar problem?? I am not a full-time programmer so my knowldge of PICs is adequate, but not expertise. Any recommendations?

I tested all other RA and RC pins and they all toggle 0V to Vdd when I tell them to. It is just this RA4 pin which is causing me greif.

I have attached a sample program in a .asm file which shows my errors.

Thanks All!

 

[cobra1]

Have you checked the datasheet?? it might be a floating pin, requiring it to be pulled high or low..

 

[Steve311]

Hi Cobra; Thanks for the response. Yes, I have checked the datasheet and I see no indication that this pin should be any different than any of the other RA or RC ports. I can just ground this pin in my final application circuit but I would like to use it if possible. I was thinking it is something I am missing in the .asm file but again, I am not sure at this point. Thanks again.

Steve

 

[colin55]

1. Put a LED and resistor on the pin to see if any current is present.
2. Use an analogue multimeter to read the pin.

 

[nickelflippr]

It's RA4 right? not RA3 as stated in thread title. Try _INTRC_OSC_NOCLKOUT in config, as it looks like the clkout is on by default.

 

[Pommie]

My guess would be that you have selected "101 = INTOSC oscillator: CLKOUT function on RA4/OSC2/CLKOUT pin, I/O function on RA5/OSC1/CLKIN" in your config settings.

Edit, looks like nickelflippr beat me to it.

Mike.

 

[blueroomelectronics]

Off the top of my head RA4 is an open collector output. Take a look at the block diagram for PORTA

 

[Pommie]

Off the top of my head RA4 is an open collector output. Take a look at the block diagram for PORTA

Not on the 684.

Mike.