PIC18F8720 PORTD problem

[nverma]

Yes, watchdog timer and low voltage programming disabled. And im running the PIC at 5 V.

[mister_e]

What happen if you do a SEROUT loop and skip the PORT reading?

Which device programmer, PBP and MPASm version are you using?

[nverma]

If I skip reading the port and just do a SEROUT loop, then I always read the initial value that was input on the port at the time of reset. Like I said, if the PIC is reset, it does read the port with the correct inputs. It just doesn't read continuously during the program at every reading. Its almost like the port stop working after reset. I am using melabs programmer v4.10, MicroCode studio v2.3.

[skimask]

If I skip reading the port and just do a SEROUT loop, then I always read the initial value that was input on the port at the time of reset. Like I said, if the PIC is reset, it does read the port with the correct inputs. It just doesn't read continuously during the program at every reading. Its almost like the port stop working after reset. I am using melabs programmer v4.10, MicroCode studio v2.3.

Which version of PBP?

[nverma]

Oh sorry, v2.46a

[skimask]

Oh sorry, v2.46a

This is what I see for PBP 2.47 that might relate to your problem...

--Adds minor optimizations for PIC18Xxxxx.
--Changes internal bit names to avoid possible conflicts.
--Fixes possible memory allocation of word-sized variable at odd address on page boundary for PIC18Xxxxx.

Will any of these have an effect? Who knows...
Have you thought about swapping out the '8720 for an '8722?

[nverma]

Well I would replace the 8720 with the 8722 if I had a choice, however I am working on an existing design which uses a 8720, so I am forced to use 8720 and PORTD. I would have changed the port as well, but I no choice.