analog values on AN0

[picozero]

Hi
I am using a PIC16F690, programming wiht a MPLAB IDE of a startkit 2 in connection with a HITECH compiler for C.

What I'd like to do is to display on a 7segments a tension value coming from an Input. How can I read the exact value from the ADC ? I mean I receive 3.2V on AN0 and with a case I detect something 3<x<4 and I set the output of a 7segments as 3(0b1111001) . So far I was only able to read if it was High or Low:

 #include <htc.h>
 __CONFIG(MCLREN & UNPROTECT & WDTDIS  & INTIO);
 
 void main() 
 {
      ANSEL = 0b10010000;    // Select A/D inputs 
      ANSELH =0b00000000; 
      ADCON0 =0b00000000;    // left justified                    
 
      CM1CON0 = 0; //Turn off comparator
      CM2CON0 = 0; //Turn off comparator
      TRISA = 0b011101; //Set pin in output mode
      TRISB = 0; //Set pin in output mode
      TRISC = 0; //Set pin in output mode
 
     // ANALOG CHANNEL 1 (AN0)
     while(1==1)    
     {
              CHS0 = 1; // set channel AN0    
              GODONE = 1;    // start the A-to-D process     
              while(GODONE) continue; 
               int advalue = ADRESH;// A-to-D result to "advalue"
 
              //This "if" can be change in a case where depending the value I activate differently the 7segments
              if(advalue)
             {
                              PORTA =    0b11111111;
                              PORTB =    0b11111111;
                              PORTC =    0b11111111;
              }
              else
             {
                              PORTA =    0b00000000;
                              PORTB =    0b00000000;
                              PORTC =    0b00000000;
              } 
        }
 };

The strange thing is also that when I send a low value to AN0, the outputs don't turn off completely but it is like they dim a bit.
Thanks in advance

 

[RufusVS]

I think it is unusual to open an analog input signal as an output.
I think you've also misinterpreted CHS0. It is not a bit to select the channel, it is
one of a set of bits which selects a channel number. Read the data sheet more carefully and look at the diagrams.

To do an A/D conversion you have to:

Set the port as A/D input
Select an ADC conversion clock
TURN ON the ADC unit
Select the channel to convert
Set the go/done bit and wait for it to clear
Read the result

(Now that I typed that, I see it is almost verbatim of 9.2.6 of the data sheet)

ANSEL= 0b00000001;  // channel AN0 (RA0) as analog in (0bxxxxxxx1)
TRISA = 0b00000001; // set port as input (0bxxxxxxx1)
ADCON1 = 0b01110000; // use internal oscillator
ADCON0 = 0b00000001; // left justified, Vdd ref, Channel 0, ADON
ADC_WARMUP_DELAY(); // create a function or macro to wait a bit. (datasheet 9.3)
GODONE=1; // start conversion
while (GODONE) continue;
advalue = ADRESH;

Should about do it. (But I'm still new at this)

Rufus