pic 12f683 adc help please

[Helgeland]

Hello i try to understand the use of the adc converter in 12f683.
i have found som code on the internet but i dont know how to modify.

i have testet this code and it works . this give me a 8bit result from AN3
and present the result as a stream of pulses on GPIO.1 just to monitor the funktion of the adc.

can someone help me modify the code for this so i can read AN0 + AN1 and store them as adval1 and adval2.
the rest of the ports are digital i/o.

the workin example code.

' Define ADCIN parameters
Define ADC_BITS 8 ' Set number of bits in result
Define ADC_CLOCK 3 ' Set clock source (3=rc)
Define ADC_SAMPLEUS 50 ' Set sampling time in uS
ANSEL = %00111000 ' Set AN3 analog, rest digital
CMCON0 = 7 ' Analog comparators off

adval Var byte ' Create adval to store result
GPIO.1=0
Pause 500 ' Wait .5 second for LCD to init
mainloop:
ADCIN 3, adval ' Read channel 3 to adval

Pulsut: 'pulses
high GPIO.1
pause 5
low GPIO.1
pause 5
adval=adval - 1
if adval>0 then pulsut
pause 100
Goto mainloop ' new reading.
End

[Heckler]

here is an example of reading an AD input on a 12F683... you will have to adapt it to your needs.

don't forget that pin RA4 is analog input 3. also don't forget that RA3 defaults to MCLR and also can ONLY be an input, never an Output.

'12F683
'****************************************************************
'*  Name    : UNTITLED.BAS                                      *
'*  Author  : [select VIEW...EDITOR OPTIONS]                    *
'*  Notice  : Copyright (c) 2007 [select VIEW...EDITOR OPTIONS] *
'*          : All Rights Reserved                               *
'*  Date    : 12/24/2007                                        *
'*  Version : 1.0                                               *
'*  Notes   :                                                   *
'*          :                                                   *
'****************************************************************
 DEFINE DEBUG_REGG GPIO        'set debug port to gpio
 DEFINE DEBUG_BIT 0             'use pin 0 for debug
 DEFINE DEBUG_BAUD 2400         'set baud rate to 2400
 DEFINE DEBUG_MODE 0            'communicate in true mode
' -----[ Initialization ]--------------------------------------------------
Reset:
TRISIO = %11001100    'configure GPIO.0,1,4,5 as outputs, gpio.2 as input
ansel  = %00000100    'and set gpio.2 as analog
cmcon0 = %00000111    'turn off the comparator
adcon0 = %00001011   'left jstfied,vdd,x,x,an2,an2,start,adc on
define adc_bits 8            'set up the a/d converter
define adc_clock 3
define adc_sampleus 50
adval var byte
' -----[ Program Code ]----------------------------------------------------
 
main:
adcin 2,adval
if adval=0 then main
debug "ad val= ",#adval,$0D,$0A
'pause 500
goto main

[Fernando]

Hello Helgeland

In order to configure the analog pins you have to write to som internal pic registers ADCON0 , ANSEL and TRISIO registers.

Here is a link to a very useful document describing PIC12F675 and 12F683 settings.
Look to page 10 to 14

http://members.shaw.ca/picgroup/Reso...Cadilly-13.pdf

Hope this helps you

[AvionicsMaster1]

Wow, that link is the shiznits. I wish that link was around about a year ago when I started using the 12f683 for a few projects. Great info.