fg004_a1/ADC.c

/*
 * Author: username
 * Date: 2024 
 * filename: ADC.c
 * description: module_purpose
 */

#include "ADC.h"
#include "RegEdit.h"
#include "avr/io.h"

static uint8_t porta_out;
static uint8_t porta_dir;

static bool IsInvalidPin(uint8_t pin_num){
    if(pin_num > 7){
        return true;
    }
    return false;
}


void ADC_Init(uint8_t pin_num)
{
    //Save the porta status.
    porta_out = PORTA.OUT;
    porta_dir = PORTA.DIR;
    
    if(IsInvalidPin(pin_num)){return;}

    //set the direction to input 
    RegEdit_SetBit((void *) &PORTA.DIRCLR, pin_num);

    //Disable the pull-up resistor
    RegEdit_SetBit((void *) &PORTA.OUTCLR, pin_num); 
 
    //Disable input buffer
    //We do some kind of nasty address addition but it saves
    //memory and means we don't need a switch statement.
    //PORT_ISC_INPUT_DISABLE_gc
    RegEdit_SetBit(
            (void *) (&PORTA.PIN0CTRL)+pin_num,
            PORT_ISC_INPUT_DISABLE_gc
            );
            /*
    RegEdit_OR_Num(
            (void *) (&PORTA.PIN0CTRL)+pin_num,
            PORT_ISC_INPUT_DISABLE_gc
        );*/
 
    //Ensure we use full 10bit resolution 
    RegEdit_ClearBit((void *) &ADC0.CTRLA, 2);

    //Use VDD as our voltage refernce.
    RegEdit_SetBit((void *) &ADC0.CTRLC, 4);

}


void ADC_Enable(uint8_t pin_num)
{
    if(IsInvalidPin(pin_num)){return;}

    //Use muxpos to select pins for ADC to connect.
    RegEdit_OR_Num((void *) &ADC0.MUXPOS, pin_num);

    //Set the enable bit in the CTRLA register
    RegEdit_SetBit((void *) &ADC0.CTRLA, 0);
}


void ADC_Disable()
{
    //Set for no ADC connections.
    RegEdit_ClearRegister((void *) &ADC0.MUXPOS);

    //Clear the enable ADC flag
    RegEdit_ClearBit((void *) &ADC0.CTRLA, 0);
    
    //Restore the port registers
    PORTA.OUT = porta_out;
    PORTA.DIR = porta_dir;
}


uint16_t ADC_ReadValue_Impl(uint8_t pin_num)
{
    RegEdit_SetNum((void *) &ADC0.COMMAND, ADC_STCONV_bm);

    /* Wait until ADC conversion done */
    //while ( !(ADC0.INTFLAGS & ADC_RESRDY_bm) )
    //while(!(RegEdit_IsBitSet((void *) &ADC0.INTFLAGS, ADC_RESSEL_bm)))
    while ( !(ADC0.INTFLAGS & ADC_RESRDY_bm) )
    {
        ;
    }
   
    /* Clear the interrupt flag by writing 1: */
    ADC0.INTFLAGS = ADC_RESRDY_bm;
 
    return (uint16_t) ADC0.RES;
}


//Set the default for the function pointer.
uint16_t (*ADC_ReadValue)(uint8_t pin_num) = ADC_ReadValue_Impl;