PIC18F8720 PORTD problem

[skimask]

DEFINE  OSC	20
DEFINE ADC_BITS 10
DEFINE ADC_SAMPLEUS 25
INCLUDE "MODEDEFS.BAS"
intcon.7=1:memcom.7=1: pspcon.4:trisd=$ff:channel var byte
outputab var bit:ch_onoff var bit:sysen var bit:channel=0: outputab=0
ch_onoff=0:sysen=0
loop:
channel=portd:channel=channel & $1F: outputAB=portd.5:ch_onoff=portd.6
sysen=portd.7:pause 500
serout portb.4,n9600,["Channel = ",#channel,13,"Output AB ",#outputAB,13,"Channel ON/OFF = ",#ch_onoff,13,"SYSEN = ",#SYSEN,13]
goto loop
end

Which revision of the '8720 do you have?
The early ones had REAL, documented problems running above 4Mhz. The problems varied and depended mainly on the code running, some things worked fine, others didn't. Try running your program at 4Mhz or less once and see if it works.
I had issues with the early ones awhile back, couldn't figure it out. Read the errata sheets about the 4Mhz problem. Tried running programs at both 4Mhz and 10Mhz...4Mhz worked, 10Mhz didn't, and this was only blinking LEDs.
After I got a few of the new revisions, the problems went away.
And I simplified your program a bit...

[nverma]

I think I have a recent version of 8720 and I'm running it at 20 MHz. I really can't try running it slower because the PIC is already assembled with a 20 MHz osscilator. Any other suggestions?

[skimask]

I think I have a recent version of 8720 and I'm running it at 20 MHz. I really can't try running it slower because the PIC is already assembled with a 20 MHz osscilator. Any other suggestions?

What are the markings on the top of the '8720 itself?

[skimask]

I think I have a recent version of 8720 and I'm running it at 20 MHz. I really can't try running it slower because the PIC is already assembled with a 20 MHz osscilator. Any other suggestions?

What are the markings on the top of the '8720 itself?
What voltage are you running the PIC at?

[Charles Linquis]

I, too, found some real weirdness with early
8720s. They were the only chip big enough to
handle my task, so I couldn't switch to another
device or slow it down. I found myself doing all
sorts of work-arounds to get it to work.

The "late model" (July 2005 and later) 8720s and the
8722's are fine.


Something you might try -
Read PORTD with one instruction

Something like:

PORTDMirror = PortD

channel.bit0 = PORTDMirror.0
channel.bit1 = PORTDMirror.1
channel.bit2 = PORTDMirror.2
channel.bit3 = PORTDMirror.3
...

[nverma]

Markings are as follows:

PIC18F8720
-I/PT
05473PP

And I tried reading the whole port at once aswell. It didn't make any difference. Wow something so simple, I really wonder what the problem is now.

[skimask]

Markings are as follows:

PIC18F8720
-I/PT
05473PP

And I tried reading the whole port at once aswell. It didn't make any difference. Wow something so simple, I really wonder what the problem is now.

Date code of 0547...that makes it a newer revision...

Watchdog timer disabled?

[nverma]

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