PIC18F25K20 PIN_A2 and A3 stops to be analog

[micro_debugger]

Hi,

I'm using the PIC18F25K20. In the application I'm developing the A2 and A3 are used as an analog pins and all other pins (of the Port A) as digital outputs. The system is running and everything seems to be OK ( I can read the A/D converter). However when I'm writing to to the RA6 or RA7 or RA5 a "high", the A/D on the A2 and A3 return 1023. When I write again "low" to the RA5 or RA6 or RA7,the A/D on the A2 and A3 return "normal value" of 350.


On the same Port A the A0 and A1 are also analog, but writing to RA7 and RA6 or RA5 not affect the A/D reading.

Any ideas or help?
Compiler Version 5.048

Going to be crazy.. .

Thank you in advance
Best Regards

[PCM programmer]

Post a short, complete test program that shows the problem.

[temtronic]

compiling in 'release' mode and NOT 'debug' ??

Jay

[micro_debugger]

Hi,
compile in release.

It is a big project, so making an example takes time, will provide by tomorrow.
Thank you

Best Regards

[Ttelmah]

The first thing to be checking is that there isn't something like a solder whisker. I've used all the pins on these chips with no sign of any problems like this, and it looks suspiciously like the analog signal may actually be being taken high, or whatever you are driving off RA5,6 and 7, may be pulling the ADC VREF down...

[micro_debugger]

Hi,

It is not hardware as itself problem, because there are many PCB (all) running at the same way. So it is hardware (design) or software problem. Doing the demo software I make more specific my problem and soon will provide all data to you.
Thank you for your quick response.

Best Regards

[micro_debugger]

Hi,

It was finally hardware designing problem, a 5 V applied to this pin for a very short time.

Thank you for your support.

Best Regards

[Ttelmah]

I felt it had to be hardware somewhere....
Glad you found it.