Corominas Marc

ADC PROBLEM - MC908SQG4

Discussion created by Corominas Marc on Mar 19, 2009
Latest reply on Mar 19, 2009 by bigmac

Hi,

 

I'm using the MC908SQG4 (pdip 8 pins) for adquire two volatge levels using the ADC module. I don't need and interruption during the normal opreration so I decide to use a polling software solution, and here begins the problem. I'm just debbuging some test code  just to verify the adquisition method, and when I start the conversion as soon as i choose the input channel the COCO flag is set to 1, and finish the conversion process without result (ok result equals 0) here is the code

 

ADC configuration:

 

void initCAD(){

    //0001 1000
    ADCCFG_ADICLK=0;
    ADCCFG_MODE=2; //10 --> 10 bits
    ADCCFG_ADLSMP=1;
    ADCCFG_ADIV=0;
    ADCCFG_ADLPC=0;
   
      ADCSC2=0x00;
   
    //0001 1111
    ADCSC1_ADCH=0x1F;   
    ADCSC1_ADCO=0;
    ADCSC1_AIEN=0;
   
    //0000 0011 PTAD0+PTAD1
        
    APCTL1=0x03;
}

 

main loop:

 

 for(;:smileywink: {
 
    delay1ms();
    
    ADCSC1_ADCH=0x01;   --> here I select CH0 or CH1    and COCO flag is SET  
    while (!ADCSC1_COCO) ;
   
    ADCSC1_ADCH=0x1F; --> disable de ADC module   
    resL=ADCRL;
    resH=ADCRH; 
 
 
  } /* loop forever */

 

Anybody can help me? I miss something but I'm not abble to find it!

 

 

Thx for all,

 

 

Added p/n to subject.

Message Edited by NLFSJ on 2009-03-19 12:36 PM

Outcomes