1.2.2 1.9.1 Analog-to-Digital Converter (ADC)

Up to 12-bit resolution of the numerical output, signed or unsigned
Signed outputs left- or right-adjusted
Up to 5.14 Msps conversion rate per channel
Up to 4 Shared Analog ADC SAR cores (bound by limited CSR and pin-out resources) for an aggregate conversion rate of 20.5 Msps per entire ADC module by performing up to 4 conversions simultaneously
Up to 64 analog inputs (maximum of 16 channels per core).
Single-ended and/or differential inputs on a per channel basis for all channels.
Up to 16 trigger sources, off-chip hardware or on-chip hardware or software generated
Edge or level active triggering modes, to generate single conversions or bursts of conversions
A scan trigger per each shared Analog ADC SAR Core to start a scan cycle which can individually include or not any of the analog inputs assigned to that Analog ADC SAR Core
Up to 4 scan cycles running simultaneously
Any channel can select any of the 16 trigger sources or the scan trigger as its own trigger
The scan trigger itself can select any of the 16 trigger sources as its own source Programmable sampling time, individual for each shared Analog ADC SAR Core
Each analog input / channel output register can be read from an general dedicated APB output register (user writes the CORDYID and CHRDYID then reads the CHRDYDATA register).

Using The Library

Interrupt mode:

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

#define ADC_VREF                             (3.3f)

volatile uint32_t adc_data[3];
volatile bool adc_sequence_done = false;
volatile bool adc_ch2_done = false;
float adc_inp_vol;
// *****************************************************************************
// *****************************************************************************
// Section: Main Entry Point
// *****************************************************************************
// *****************************************************************************
void ADC_EventHandler(ADC_CORE_INT status, uintptr_t context)
{
    /* ADC1_CH0 and ADC1_CH1 are configured for scan trigger */
    if (status & ADC_CORE_INT_EOSRDY)
    {                
        adc_data[0] = ADC_ResultGet(ADC_CORE_NUM1, ADC_CH0);
        
        adc_data[1] = ADC_ResultGet(ADC_CORE_NUM1, ADC_CH1);
        
        adc_sequence_done = true;
    }
    /* ADC1_CH2 is configured for Global (Edge) Software trigger */
    if (status & ADC_CORE_INT_CHRDY_2)
    {
        adc_data[2] = ADC_ResultGet(ADC_CORE_NUM1, ADC_CH2);
        
        adc_ch2_done = true;
    }
}

int main ( void )
{
    /* Initialize all modules */
    SYS_Initialize ( NULL );
    
    printf("\r\n *********************************************** \r\n");
    printf("\r\n           ADC INTERRUPT DEMO \r\n");
    printf("\r\n *********************************************** \r\n");
    
    ADC_CORE1CallbackRegister(ADC_EventHandler, 0);    
    RTC_Timer32Start();

    while ( true )
    {
        if (SWITCH_Get() == 0)
        {
            // Wait for switch release
            while (SWITCH_Get() == 0);
            
            ADC_GlobalEdgeConversionStart();
        }
        
        if (adc_sequence_done == true) 
        {
			adc_sequence_done = false;
                                    
            adc_inp_vol = (uint16_t)adc_data[0] * ADC_VREF / 4095U;
            
            printf("\r\n ADC1_AIN0: ADC Count: 0x%03x, ADC Input Voltage = %d.%02d V \r\n", 
                    (uint16_t)adc_data[0], (int)adc_inp_vol, (int)((adc_inp_vol - (int)adc_inp_vol)*100.0));
            
            adc_inp_vol = (uint16_t)adc_data[1] * ADC_VREF / 4095U;
            
            printf("\r\n ADC1_AIN1: ADC Count: 0x%03x, ADC Input Voltage = %d.%02d V \r\n", 
                    (uint16_t)adc_data[1], (int)adc_inp_vol, (int)((adc_inp_vol - (int)adc_inp_vol)*100.0));
		}       
        if (adc_ch2_done == true)
        {
            adc_ch2_done = false;
            
            adc_inp_vol = (uint16_t)adc_data[2] * ADC_VREF / 4095U;
            
            printf("\r\n ADC1_AIN2: ADC Count: 0x%03x, ADC Input Voltage = %d.%02d V \r\n", 
                    (uint16_t)adc_data[2], (int)adc_inp_vol, (int)((adc_inp_vol - (int)adc_inp_vol)*100.0));
        }
    }

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

    return ( EXIT_FAILURE );
}

Polling mode:

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

#define ADC_VREF                             (3.3f)

// *****************************************************************************
// *****************************************************************************
// Section: Main Entry Point
// *****************************************************************************
// *****************************************************************************
uint32_t adc_data;
float adc_inp_vol;

int main ( void )
{
    /* Initialize all modules */
    SYS_Initialize ( NULL );
    
    while ( true )
    {
        ADC_GlobalEdgeConversionStart();
        
        while (ADC_ChannelResultIsReady(ADC_CORE_NUM1, ADC_CH0) == false);
        
        adc_data = ADC_ResultGet(ADC_CORE_NUM1, ADC_CH0);
        
        adc_inp_vol = (uint16_t)adc_data * ADC_VREF / 4095U;
            
        printf("ADC1_AIN0: ADC Count: 0x%03x, ADC Input Voltage = %d.%02d V\r", 
            (uint16_t)adc_data, (int)adc_inp_vol, (int)((adc_inp_vol - (int)adc_inp_vol)*100.0));
    }

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

    return ( EXIT_FAILURE );
}

Library Interface

ADC Controller peripheral library provides the following interfaces:

Functions


Name	Description
ADCx_Initialize	Initializes given instance of ADC peripheral
ADCx_Enable	Enables the ADC module
ADCx_Disable	Disables the ADC module
ADC_CompareEnable	Enables digital comparisons for the given channel on the specified ADC core
ADC_CompareDisable	Disables digital comparisons for the given channel on the specified ADC core
ADC_CompareWinThresholdSet	Configures the low and high threshold values for the comparator on the specified ADC core
ADC_CompareWinModeSet	Configures the low and high threshold values for the comparator on the specified ADC core
ADC_GlobalInterruptsStatusGet	Returns the global interrupt status
ADC_CoreInterruptsEnable	Enables the specified ADC core's interrupt
ADC_CoreInterruptsDisable	Disable the specified ADC core's interrupts
ADC_CoreInterruptsStatusGet	Returns the specified ADC core's interrupt status
ADC_CoreInterruptsStatusClear	Clears the specified ADC core's interrupt status
ADC_GlobalEdgeConversionStart	Generates global edge trigger and starts conversion on channels configured with Global edge as the trigger source
ADC_GlobalLevelConversionStart	Starts global level trigger and starts conversion on channels configured with Global level as the trigger source
ADC_GlobalLevelConversionStop	Stops global level trigger and stops conversion on channels configured with Global level as the trigger source
ADC_SyncTriggerEnable	Enables sync trigger defined by CTRLC.CNT value
ADC_SyncTriggerDisable	Disables sync trigger
ADC_SyncTriggerCounterSet	Configures the value of CTRLC.CNT register
ADC_SoftwareControlledConversionEnable	Enables software controlled conversion on the specified ADC core's channel
ADC_ChannelSamplingStart	Enables the Analog Mux Input and starts sampling on the ADC core and channel that was specified using the ADC_SoftwareControlledConversionEnable() API
ADC_ChannelSamplingStop	Stops sampling on the ADC core and channel that was specified using the ADC_SoftwareControlledConversionEnable() API
ADC_ChannelConversionStart	Starts conversion on the ADC core and channel that was specified using the ADC_SoftwareControlledConversionEnable() API
ADC_ChannelResultIsReady	Indicates whether ADC conversion is complete on the specified ADC core's channel
ADC_EOSStatusGet	Indicates whether End of scan interrupt flag is set on the specified ADC core
ADC_ResultGet	Returns the ADC conversion value for the specified ADC core channel
ADC_FIFORead	Returns a single ADC conversion value from the ADC FIFO
ADC_FIFOBufferRead	Returns multiple ADC conversion values from the ADC FIFO
ADC_GlobalCallbackRegister	Registers the global callback function
ADC_COREnCallbackRegister	Registers the ADC core specific callback function

Data types and constants


Name	Type	Description
ADC_CORE_INT_CMPHIT	Macro	Identifies ADC core interrupt status
ADC_FIFO_CORID_GET	Macro	Returns the ADC core id in the ADC FIFO data
ADC_FIFO_DATA_GET	Macro	Returns the ADC conversion resunt from the ADC FIFO data
ADC_FIFO_CHNID_GET	Macro	Returns the ADC channel id in the ADC FIFO data
ADC_FIFO_CNT_GET	Macro	Returns the current number of entries present in the ADC FIFO
ADC_GLOBAL_INT_CRRDY1	Macro	Identifies ADC global interrupt status
ADC_CHANNEL_NUM	Enum	Identifies ADC channel number
ADC_CORE_NUM	Enum	Identifies ADC core
ADC_CORE_CALLBACK	Typedef	Defines the function pointer data type and function signature for the adc peripheral core callback function
ADC_GLOBAL_CALLBACK	Typedef	Defines the function pointer data type and function signature for the adc peripheral global callback function
ADC_CORE_CALLBACK_OBJECT	Struct	ADC Core events Callback structure
ADC_GLOBAL_CALLBACK_OBJECT	Struct	ADC Global Callback structure