ADC with Potentiometers - Help!

[seejayjames]

I'm having trouble getting more than just one ADC pin to work on my P16877A. I can get pin 2 (A0) to work just fine, but none of the others. I think I'm not setting up the parameters right. Also, do I need to reset something after each sample?

I eventually want to have eight 8-bit dials hooked up to the 8 ADC inputs and sample them constantly (to control music parameters in Max/MSP ;)

Here's the relevant parts of the code. Thanks in advance to whoever has some info! ;)

-------------------------------------------------------------

define osc 20
INCLUDE "modedefs.bas"

DEFINE ADC_BITS 8
DEFINE ADC_CLOCK 4
DEFINE ADC_SAMPLEUS 20

TRISA = 255
ADCON1 = %00000010

'------------------------------------------------------------------

pot_pin_2 var PORTA.0 'set potentiometer to go in pin 2 (A0)
pot_pin_3 var PORTA.1 'set potentiometer to go in pin 3 (A1)

'vars for potentiometer info
var_pot_2 var byte
var_pot_3 var byte

main_loop:

ADCIN pot_pin_2, var_pot_2 ' Read pin 2 to var_pot_2
var_pot_2 = (255 - var_pot_2) ' Invert result to match dial direction L/R

serout serial_out_pin,T9600,["Sending POT PIN 2... ",#var_pot_2,10,13]

pause 700

'----------------------------------------------------------

ADCIN pot_pin_3, var_pot_3 ' Read pin 3 to var_pot_3
var_pot_3 = (255 - var_pot_3) ' Invert result to match dial direction

serout serial_out_pin,T9600,["Sending POT PIN 3... ",#var_pot_3,10,13]

pause 700

goto main_loop

[Patrick]

Played a bit

Here is a working example on a 16F876

'==========================================
'P van Biljon
'Servo test program
'Text for two servo,s
'29 June 2006
'Pic 16F876-04
'Good for two Servo's
'==========================================

potCW1 var portc.0
potccw1 var portc.1
Servo1 var portc.2

potCW2 var portc.3
potccw2 var portc.4
Servo2 var portc.5

rcrt1 var word
rclf1 var word
Pos1 var word

rcrt2 var word
rclf2 var word
Pos2 var word
'==========================================
DEFINE LOADER_USED 1 ' If using bootloader to program pic

Init:

adcon1 = 7
trisc = %00000000

Main: gosub pot1
gosub pot2

pot1:
HIGH potcw1
HIGH potccw1


pause 5

rctime potcw1,1,rcrt1
rctime potccw1,1,rclf1
rcrt1 = rcrt1 */ $0068 max 250
rclf1 = rclf1 */ $0068 max 250
pos1 = rcrt1 - rclf1
pulsout servo1,(200 + pos1)
pause 5
return
Pot2:
HIGH potcw2
HIGH potccw2

Pause 5

rctime potcw2,1,rcrt2
rctime potccw2,1,rclf2
rcrt2 = rcrt2 */ $0068 max 250
rclf2 = rclf2 */ $0068 max 250
pos2 = rcrt2 - rclf2
pulsout servo2,(200 + pos2)
pause 5

goto main


with .1qF caps on pot connected to +5 Volts

Patrick

[seejayjames]

Thanks Patrick! Will definitely try out the code on my chips. I think it was something to do with the pauses, or perhaps the rctime. Hope to get it working so I can utilize those ADC's.

Thanks again!
-CJ