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##

# 3.44.2 Analog Digital Converter (ADC)

- 8-bit, 10-bit or 12-bit resolution

- Up to 1,000,000 samples per second (1 MSPS)

- Differential and single-ended inputs

- Five internal inputs

- Single, continuous, and sequencing options

- Windowing monitor with selectable channel

- Built-in internal reference and external reference options

- Event-triggered conversion for accurate timing (one event input)

- Optional DMA transfer of conversion settings or result

- Hardware gain and offset compensation

- Averaging and oversampling with decimation to support up to 16-bit result

- Selectable sampling time

- Flexible Power or Throughput rate management

## Using The Library

ADC Sample:

    #include <stddef.h>                     // Defines NULL
    #include <stdbool.h>                    // Defines true
    #include <stdlib.h>                     // Defines EXIT_FAILURE
    #include <stdio.h>
    #include "definitions.h"                // SYS function prototypes

    #define ADC_VREF                (3.3f)
    #define DAC_COUNT_INCREMENT     (31U)  // equivalent to 0.1V(0.1 / (3.3 / ((2^10) - 1)))
    #define DAC_COUNT_MAX           (1023U)

    uint16_t adc_count;
    float input_voltage;
    /* Initial value of dac count which is midpoint = 1.65 V*/
    uint16_t dac_count = 0x200;

    void switch_handler(uintptr_t context )
    {
        /* Write next data sample */
        dac_count = dac_count + DAC_COUNT_INCREMENT;

        if (dac_count > DAC_COUNT_MAX)
                dac_count=0;

        DAC_DataWrite(dac_count);
    }

    // *****************************************************************************
    // *****************************************************************************
    // Section: Main Entry Point
    // *****************************************************************************
    // *****************************************************************************

    int main ( void )
    {
        /* Initialize all modules */
        SYS_Initialize ( NULL );

        printf("\n\r---------------------------------------------------------");
        printf("\n\r                    ADC Sample Demo                 ");
        printf("\n\r---------------------------------------------------------\n\r");

        ADC0_Enable();
        SYSTICK_TimerStart();
        EIC_CallbackRegister(EIC_PIN_3, switch_handler, (uintptr_t) NULL);
        DAC_DataWrite(dac_count);
        while (1)
        {
            /* Start ADC conversion */
            ADC0_ConversionStart();

            /* Wait till ADC conversion result is available */
            while(!ADC0_ConversionStatusGet())
            {

            };

            /* Read the ADC result */
            adc_count = ADC0_ConversionResultGet();
            input_voltage = (float)adc_count * ADC_VREF / 4095U;

            printf("ADC Count = 0x%03x, ADC Input Voltage = %d.%02d V \r", adc_count, (int)input_voltage, (int)((input_voltage - (int)input_voltage)*100.0));

            SYSTICK_DelayMs(500);
        }

        /* Execution should not come here during normal operation */

        return ( EXIT_FAILURE );
    }

## Library Interface

Analog Digital Converter peripheral library provides the following interfaces:

Functions

Name | Description
--- | ---
ADCx_Initialize | Initializes given instance of ADC peripheral
ADCx_Enable | Enables given instance of ADC peripheral
ADCx_Disable | Disables given instance of ADC peripheral
ADCx_ChannelSelect | Selects ADC input channel
ADCx_ConversionStart | Starts the ADC conversion with the software trigger
ADCx_ConversionStatusGet | Returns the status of the conversion of the channel
ADCx_ConversionResultGet | Returns the conversion result of the channel
ADCx_ConversionSequenceIsFinished | Returns the status of automatic sequence conversion
ADCx_WindowMonitorStatusGet | Returns the status of the window monitor flag
ADCx_ComparisonWindowSet | Returns the status of automatic sequence conversion
ADCx_CallbackRegister | Registers the function to be called from interrupt

Data types and constants

Name | Type | Description
--- | --- | ---
ADC_STATUS | Enum | Identifies ADC interrupt flag status
ADC_POSINPUT | Enum | Identifies ADC positive input pin to select
ADC_NEGINPUT | Enum | Identifies ADC negative input pin to select
ADC_CALLBACK | Typedef | Defines the data type and function signature for the ADC peripheral callback function