Pot reading jumping like crazy!!!

[champion]

A wall type plugpack or a benchtop powersupply?

Have your tried buying another linear potentiometer?

what about your LCD display?
Start up pause?
are you clearing the display or just writing over old values?

I assume you have a PIC 16F84A with the appropriate powersupply, a crystal...an LCD and POT attached with 2 wires and a cap. Right?

When you say it moves erratically, does it move 1 or 2 values up or down during idle? Or does it move in much bigger increments?

1. I'm using a wall type plugback

2. I have tried 5 different pots. all the same

3. Here is my output for the lcd
lcdout $FE, 1, "Damper Position", $FE, $C0, " ", dec dig3, dec dig2, ".", dec dig1, dec dig0, "mm"

4. I am using a 4MHz crystal, and the pot connected with 2 wires only.

5. The values change by 1-2 units out of 255 total units.

Also, when I allow the program to run continuously, the value steadily drops until it levels off at a certain point, far from where it started.

[Archangel]

1. I'm using a wall type plugback

2. I have tried 5 different pots. all the same

3. Here is my output for the lcd
lcdout $FE, 1, "Damper Position", $FE, $C0, " ", dec dig3, dec dig2, ".", dec dig1, dec dig0, "mm"

4. I am using a 4MHz crystal, and the pot connected with 2 wires only.

5. The values change by 1-2 units out of 255 total units.

Also, when I allow the program to run continuously, the value steadily drops until it levels off at a certain point, far from where it started.

Hi Champion,
Do I understand this correctly, You are dividing 5 volts by 255 ?
If so then each unit has a value of 0.0196078431372549019607843137254902, so if it only varies by 2 or 3 units,
let's say 10 units just because math frightens me then variation =0.196078431372549019607843137254902. now factor in the inherent instability of the power supply's regulator, the terrific connections you get from the breadboards connectors, and if there are any air currents near your bench to cause variations in the temperature of any or all or this . . .<h3> MY POINT IS </h3>. . . . unless you have everything made into a solid block with constant temperature regulation and perfect power regulation then some variation is normal, I believe that was why sayzer told you to choose a smaller divisor like 30, then the variation would be less than 1 unit and you will not see it.
JS