help setting up 16F886 for ADC

[midali]

Hi to all,

I have troubles with reading 10 bit on AN0 , too .
Can somebody give me some ideas, please ?

'****************************************************************
'*  Name    : UNTITLED.BAS                                      *
'*  Author  : [select VIEW...EDITOR OPTIONS]                    *
'*  Notice  : Copyright (c) 2014 [select VIEW...EDITOR OPTIONS] *
'*          : All Rights Reserved                               *
'*  Date    : 10/2/2018                                          *
'*  Version : 1.0                                               *
'*  Notes   :                                                   *
'*          :                                                   *
'****************************************************************
'PIC16F886
   #config
   __CONFIG    _CONFIG1, _LVP_OFF & _FCMEN_OFF & _IESO_OFF & _BOR_OFF & _CPD_OFF & _CP_ON & _MCLRE_OFF & _PWRTE_ON & _WDT_OFF & _INTRC_OSC_NOCLKOUT 
   __CONFIG    _CONFIG2, _WRT_OFF & _BOR21V
   #endconfig
    
define osc 4
include "lcd886.bas"
CM1CON0 = 0 			'Comparator Off
CM2CON0 = 0 			'Comparator Off
   	
Define ADC_BITS 10 		'Set number of bits in result (10)
Define ADC_CLOCK 3 		'Set clock source (3=rc)
Define ADC_SAMPLEUS 50 	'Set sampling time in microseconds (50us)

TRISA = %00000001       'Set PORTA.0 as input
TRISB = %00000000       'Set PORTB as outputs
TRISC = %00000000       'Set PORTC as outputs

ANSEL  = %00000001      'Set PORTA.0 as analog
ANSELH = %00000000      'The rest ports are digital
'ADCON0 = %11000011      'Set adc channel = AN0
'ADCON1 = %10000000  'SETUP ADC RIGHT JUSTIFY SET REFV to VDD & VSS		        
	
PORTA = 0
PORTB = 0
PORTC = 0

light  var PORTA.3
tc     var word

'--------light is ON and initialize the LCD ---------
pause  300
high   light
gosub  lcdrst
lcdout $fe, $80,"TEST"
gosub  lcdrst

'---------------------PROGRAM------------------------
MAIN:
ADCON0 = %11000011
gosub read_tc

lcdout $fe, $80, #tc
pause 200
goto main
end

'---------------------Read AN0------------------------
read_tc:
WHILE ADCON0.1 = 1:WEND  'WAIT FOR CONVERSION
     tc.HIGHBYTE = ADRESH
     tc.LOWBYTE  = ADRESL
return
'--------------------lcd reset------------------------
lcdrst:
lcdout, $fe, 1
pause 10
return

[Ioannis]

Is it on a F886?

You MUST NOT set the GO/DONE bit at the same time you enable the ADC converter (Data Sheet page 106, Note in the box).

Also you do not setup the ADCON1. It is commented.

Try this:

        '****************************************************************
        '*  Name    : UNTITLED.BAS                                      *
        '*  Author  : [select VIEW...EDITOR OPTIONS]                    *
        '*  Notice  : Copyright (c) 2014 [select VIEW...EDITOR OPTIONS] *
        '*          : All Rights Reserved                               *
        '*  Date    : 10/2/2018                                          *
        '*  Version : 1.0                                               *
        '*  Notes   :                                                   *
        '*          :                                                   *
        '****************************************************************
        'PIC16F886
           #config
           __CONFIG    _CONFIG1, _LVP_OFF & _FCMEN_OFF & _IESO_OFF & _BOR_OFF & _CPD_OFF & _CP_ON & _MCLRE_OFF & _PWRTE_ON & _WDT_OFF & _INTRC_OSC_NOCLKOUT 
           __CONFIG    _CONFIG2, _WRT_OFF & _BOR21V
           #endconfig
            
        define osc 4
        include "lcd886.bas"
        CM1CON0 = 0 			'Comparator Off
        CM2CON0 = 0 			'Comparator Off
           	
        Define ADC_BITS 10 		'Set number of bits in result (10)
        Define ADC_CLOCK 3 		'Set clock source (3=rc)
        Define ADC_SAMPLEUS 50 	'Set sampling time in microseconds (50us)

        TRISA = %00000001       'Set PORTA.0 as input
        TRISB = %00000000       'Set PORTB as outputs
        TRISC = %00000000       'Set PORTC as outputs

        ANSEL  = %00000001      'Set PORTA.0 as analog
        ANSELH = %00000000      'The rest ports are digital
        ADCON0 = %11000001      'Set adc channel = AN0
        ADCON1 = %10000000  'SETUP ADC RIGHT JUSTIFY SET REFV to VDD & VSS		        
        	
        PORTA = 0
        PORTB = 0
        PORTC = 0

        light  var PORTA.3
        tc     var word

        '--------light is ON and initialize the LCD ---------
        pause  300
        high   light
        gosub  lcdrst
        lcdout $fe, $80,"TEST"
        gosub  lcdrst

        '---------------------PROGRAM------------------------
        MAIN:
        ADCON0.1=1
        gosub read_tc

        lcdout $fe, $80, #tc,"       " ' I put some space here when you go from large result to 1 digit result.
        pause 200
        goto main
        end

        '---------------------Read AN0------------------------
        read_tc:
        WHILE ADCON0.1 = 1:WEND  'WAIT FOR CONVERSION
             tc.HIGHBYTE = ADRESH
             tc.LOWBYTE  = ADRESL
        return
        '--------------------lcd reset------------------------
        lcdrst:
        lcdout, $fe, 1
        pause 10
        return

Ioannis