I too had problems with the 877 and a/d I was using 2 channels to measure
strobe intensity
The board I used was the board that comes with Mplab ICD , I noticed I had 2
or 3 bits unstable but found out that if I programmed stand alone code and
unplugged the ICD my readings where stable except for the jiggle 1 lsb if my
analog signal was close to the next value

After some experiments I added some caps 1uF tantal and a couple of .1 uF
ceramic on the board and have not seen this problem back.

Peter

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Edson Brusque
Sent: Friday, February 11, 2000 2:09 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: A/D fluctuation


Hello,

    I'm making a voltage reader with the internal A/D from a PIC16F877.
While my voltmeter shows that my input have steady 1.18V, PIC's A/D gives me
random values from 240 to 247. Is this normal? Is there a way to make the
A/D shows a steady reading?

    Best regards,

    Brusque

+------------------------+
|     Edson Brusque      |
| Research & Development |
|  www.citronics.com.br  |
+------------------------+