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

#ifndef __AVR_ATtiny404__
#define __AVR_ATtiny404__
#endif

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

#define MAX_PIN_NUM 7

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


void ADC_Setup(void)
{
    //Clears control register A for ADC0
    RegEdit_SetNum((void *) &ADC0.CTRLA, 0x00);

    //Sets The sample accumulation number to 32.
    RegEdit_SetNum((void *) &ADC0.CTRLB, 0x5);

    //Sets the voltage reference to VDD or VCC.
    RegEdit_SetBit((void *) &ADC0.CTRLC, 4);

    //Sets the pre-scalar for the adc sample rate.
    RegEdit_SetBit((void *) &ADC0.CTRLC, 2);

    //Setup an Initalization delay.
    RegEdit_OR_Num((void *) &ADC0.CTRLD, (2<<5));

    //Set the bit for ADC variation during readings.
    RegEdit_SetBit((void *) &ADC0.CTRLD, 4);
}

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


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

    //Disable the pull-up resistor
    RegEdit_ClearBit((void *) &PORTA.OUT, pin_num); 
 
    //Disable input buffer
    //We do some kinda nasty address addition but it saves
    //memory and means we don't need a switch statment.
    RegEdit_SetBit(
            (void *) (&PORTA.PIN0CTRL)+pin_num,
            PORT_ISC_INPUT_DISABLE_gc
            );
 
}


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


void ADC_Disable()
{
    //Clear the enable ADC flag
    RegEdit_ClearBit((void *) &ADC0.CTRLA, 0);
}


void ADC_SetPin(uint8_t pin_num)
{
    if(IsInvalidPin(pin_num)){return;}
    RegEdit_ClearRegister((void *) &ADC0.MUXPOS);
    RegEdit_SetNum((void *) &ADC0.MUXPOS, pin_num);
}


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) )
    {
        ;
    }
   
    /* Clear the interrupt flag by writing 1: */
    ADC0.INTFLAGS = ADC_RESRDY_bm;
    
    uint16_t adc_val = (uint16_t) ADC0.RES;
    adc_val = adc_val >> 5;
    return adc_val; 
}


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