what is the problem

[nfs]

i use the ccs_compiler and i try to make a program who read the voltage from the ADC, compare it to a value and send me response throug led: this is the source:

#include <16F876.h>
/* Set configuration bits in the PIC processor */
#fuses XT, NOPROTECT, NOPUT, NOWDT, NOBROWNOUT, NOLVP, NOCPD, NOWRT

#device adc=10
#device *=16
#use delay (clock=4000000) #use standard_io ( a )
#use standard_io ( b )
#use standard_io ( c )
#define led1 PIN_A1
#define led2 PIN_A2
#define led3 PIN_A3
#define Vpp 1024
#define Vppmin 973
#define Vss 0
#define Vctq 921
#define tension_maxi_touche_0 34
#define tension_mini_touche_0 0
#define tension_maxi_touche_R 790
#define tension_mini_touche_R 750
#define tension_maxi_touche_plus 523
#define tension_mini_touche_plus 463
#define tension_maxi_touche_moins 287
#define tension_mini_touche_moins 245
#bit ADFM_BIT=0x9F.7
#bit PCFG3_BIT=0X9F.3
#bit PCFG2_BIT=0X9F.2
#bit PCFG1_BIT=0X9F.1
#bit PCFG0_BIT=0X9F.0
#byte ADCON0 = 0x1f
#byte ADCON1 = 0x9f
#bit start_ad = ADCON0.2
int16 us;
int16 ADCvaleur;
static char cADCflag; /* global variable */

void InitialiseADC (unsigned char ADC_Channel)
{
setup_port_a( RA0_ANALOG );
setup_adc( ADC_CLOCK_DIV_8 );
set_adc_channel( 0 );
}


void main( void )
{
long ADCvaleur;
int i, k;
output_low (led1);
output_low (led2);
output_low (led3);

InitialiseADC(0);
ADFM_BIT=1;
PCFG3_BIT=1;
PCFG2_BIT=1;
PCFG1_BIT=1;
PCFG0_BIT=0;


output_high (led1);
delay_ms(5000);
start_ad = 1;
ADCvaleur = 0x0000;
ADCvaleur = (unsigned int16)(read_ADC(0));
delay_us(50);
if (ADCvaleur<=921)
{
output_low (led1);
output_high(led2);
delay_ms(400);
output_low(led2);
}
else
{
output_high (led3);
delay_ms(500);
output_low (led3);
}
}

thanks
_________________
nfs

[Couch]

nfs

post the version of compiler you are using, and what specific problem are you seeing (eg. not compiling, wrong a/d value)? Add more info to your post.

[SherpaDoug]

Few of us are going to wade through your code without some hint as to what we should look for. Can you tell us what goes wrong? Does it compile? Do the LEDs ever light? Do they ever go out?

Consider adding some diagnostic output, maybe from a software UART to an unused pin to tell you what the PIC thinks it is doing. Just printing the name of a subroutine every time you enter it can work wonders.

Well one thing does stand out... I don't see any looping structure. It seems you code will run once though and STOP. If you want to keep checking the A/D over and over you will have to loop your code so it keeps running.
_________________
The search for better is endless. Instead simply find very good and get the job done.

[nfs]

version 3.168
and it compiled succesfully but when i want to simulate it the ADC unit isn't working. i simulate it with ISIS and i program it on the PIC.
_________________
nfs

[ttelmah]

[rnielsen]

Make sure you have a while(1) statement in there so the code does not fall off the end and cause the PIC to fall asleep.

Try this code and see if it works for you.

[SherpaDoug]

Even the code RNIELSON supplied will only read the A/D once each time power is applied. This MIGHT be what he wants... but I doubt it. I would assume he wants a while (1) around the whole sampling and display code so the lights will change as the voltage varies.
_________________
The search for better is endless. Instead simply find very good and get the job done.

[rnielsen]

True. I put the while() at the end so he could see if the lights would change after the 5 second delay.

If at first you don't succeed, PUNT!