4.1.2.3 12-bit ADCC

API Prototypes for the ADCC driver.

• void ADCC_Initialize (void)

  Initializes the ADC module. This routine will be called before any other ADC routine.

• void ADCC_StartConversion (adcc_channel_t channel)

  Starts an A/D conversion on the selected channel.

• bool ADCC_IsConversionDone (void)

  Checks if the ongoing A/D conversion is complete.

• adc_result_t ADCC_GetConversionResult (void)

  Retrieves the result of the latest A/D conversion.

• adc_result_t ADCC_GetSingleConversion (adcc_channel_t channel)

  Retrieves the result of a single A/D conversion on the given channel.

• void ADCC_StopConversion (void)

  Stops an ongoing A/D conversion.

• void ADCC_SetStopOnInterrupt (void)

  Enables the Stop On Interrupt bit.

• void ADCC_DischargeSampleCapacitor (void)

  Discharges the input sample capacitor by setting the channel to AVss.

• void ADCC_LoadAcquisitionRegister (uint16_t acquisitionValue)

  Loads the ADC Acquisition Time Control register with the specified value.

• void ADCC_SetPrechargeTime (uint16_t prechargeTime)

  Loads the ADC Precharge Time Control register with the specified value.

• void ADCC_SetRepeatCount (uint8_t repeatCount)

  Loads the repeat counter with the specified value.

• uint8_t ADCC_GetCurrentCountofConversions (void)

  Retrieves the current value of the ADC Repeat Count register.

• void ADCC_ClearAccumulator (void)

  Clears the accumulator.

• uint24_t ADCC_GetAccumulatorValue (void)

  Retrieves the 18-bit value of the ADC accumulator.

• bool ADCC_HasAccumulatorOverflowed (void)

  Determines if the ADC accumulator has overflowed.

• uint16_t ADCC_GetFilterValue (void)

  Retrieves the value of the ADC Filter register.

• uint16_t ADCC_GetPreviousResult (void)

  Retrieves the value of the ADC Previous register.

• void ADCC_DefineSetPoint (uint16_t setPoint)

  Sets the value of the ADC Threshold setpoint.

• void ADCC_SetUpperThreshold (uint16_t upperThreshold)

  Sets the value of the ADC Upper Threshold register.

• void ADCC_SetLowerThreshold (uint16_t lowerThreshold)

  Sets the value of the ADC Lower Threshold register.

• uint16_t ADCC_GetErrorCalculation (void)

  Retrieves the value of the ADC Setpoint Error register.

• void ADCC_EnableDoubleSampling (void)

  Enables the Double Sampling bit.

• void ADCC_EnableContinuousConversion (void)

  Enables continuous conversion.

• void ADCC_DisableContinuousConversion (void)

  Disables continuous conversion.

• bool ADCC_HasErrorCrossedUpperThreshold (void)

  Determines if the ADC error has crossed the upper threshold.

• bool ADCC_HasErrorCrossedLowerThreshold (void)

  Determines if the ADC error is less than the lower threshold.

• uint8_t ADCC_GetConversionStageStatus (void)

  Retrieves the multi-stage status.

API Implementations for the ADCC driver.

ADCC Generated Driver File

• void ADCC_Initialize (void)

  Initializes the ADC module. This routine will be called before any other ADC routine.

• void ADCC_StartConversion (adcc_channel_t channel)

  Starts an A/D conversion on the selected channel.

• bool ADCC_IsConversionDone (void)

  Checks if the ongoing A/D conversion is complete.

• adc_result_t ADCC_GetConversionResult (void)

  Retrieves the result of the latest A/D conversion.

• adc_result_t ADCC_GetSingleConversion (adcc_channel_t channel)

  Retrieves the result of a single A/D conversion on the given channel.

• void ADCC_StopConversion (void)

  Stops an ongoing A/D conversion.

• void ADCC_SetStopOnInterrupt (void)

  Enables the Stop On Interrupt bit.

• void ADCC_DischargeSampleCapacitor (void)

  Discharges the input sample capacitor by setting the channel to AVss.

• void ADCC_LoadAcquisitionRegister (uint16_t acquisitionValue)

  Loads the ADC Acquisition Time Control register with the specified value.

• void ADCC_SetPrechargeTime (uint16_t prechargeTime)

  Loads the ADC Precharge Time Control register with the specified value.

• void ADCC_SetRepeatCount (uint8_t repeatCount)

  Loads the repeat counter with the specified value.

• uint8_t ADCC_GetCurrentCountofConversions (void)

  Retrieves the current value of the ADC Repeat Count register.

• void ADCC_ClearAccumulator (void)

  Clears the accumulator.

• uint24_t ADCC_GetAccumulatorValue (void)

  Retrieves the 18-bit value of the ADC accumulator.

• bool ADCC_HasAccumulatorOverflowed (void)

  Determines if the ADC accumulator has overflowed.

• uint16_t ADCC_GetFilterValue (void)

  Retrieves the value of the ADC Filter register.

• uint16_t ADCC_GetPreviousResult (void)

  Retrieves the value of the ADC Previous register.

• void ADCC_DefineSetPoint (uint16_t setPoint)

  Sets the value of the ADC Threshold setpoint.

• void ADCC_SetUpperThreshold (uint16_t upperThreshold)

  Sets the value of the ADC Upper Threshold register.

• void ADCC_SetLowerThreshold (uint16_t lowerThreshold)

  Sets the value of the ADC Lower Threshold register.

• uint16_t ADCC_GetErrorCalculation (void)

  Retrieves the value of the ADC Setpoint Error register.

• void ADCC_EnableDoubleSampling (void)

  Enables the Double Sampling bit.

• void ADCC_EnableContinuousConversion (void)

  Enables continuous conversion.

• void ADCC_DisableContinuousConversion (void)

  Disables continuous conversion.

• bool ADCC_HasErrorCrossedUpperThreshold (void)

  Determines if the ADC error has crossed the upper threshold.

• bool ADCC_HasErrorCrossedLowerThreshold (void)

  Determines if the ADC error is less than the lower threshold.

• uint8_t ADCC_GetConversionStageStatus (void)

  Retrieves the multi-stage status.

• typedef uint16_t adc_result_t

  Used for the result of the A/D conversion.

• typedef __uint24 uint24_t

• enum adcc_channel_t { channel_OPA1 = 0x39, channel_DAC2 = 0x3a, channel_VSS = 0x3b, channel_Temp = 0x3c, channel_DAC1 = 0x3d, channel_FVR_Buffer1 = 0x3e, channel_FVR_Buffer2 = 0x3f }

  Contains the available ADC channels.

ADCC Generated Driver API Header File

For new users it is recommended to start with the Timer0, UART and Data Streamer, since these components are used to support other use cases.

An ADC conversion is taken every 100 ms, on the selected analog channel. After each ADC conversion a LED is toggled and the ADC Result is sent to PC terminal using printf.

Note: Before each conversion is started, the sample capacitor is first discharged, by connecting it to the ground potential of the microcontroller.

After configuring the components as described above, click 'Generate' to generate the code. Then add the following code snippets to your application:

/* Required header files for UART Example 1 */
#include "mcc_generated_files/system/system.h"

int main(void)
{
    SYSTEM_Initialize();
    
    uint16_t volatile adcResult;

    while(1)
    {
        ADCC_DischargeSampleCapacitor();   //Discharge capacitor voltage by connecting the VSS channel
        adcResult = ADCC_GetSingleConversion(channel_ANC3); //Get the conversion result
        LED_Toggle();
        printf("The ADC Result is: %d\r\n",adcResult);

        __delay_ms(100);  
    }
}

After configuring the components as described above, click 'Generate' to generate the code. Then add the following code snippets to your application:

D,1,1,adcResult
B,1,1,adcSampleCount

#include "mcc_generated_files/system/system.h"

/* Create a pointer of type TMR_INTERFACE and assign it to the address of the Timer0 TMR_INTERFACE struct.
This enables us to get access the portable API interface, which ensures that it's easy to change the peripheral instance the timer runs on. */
const struct TMR_INTERFACE *Timer = &Timer0;
volatile bool SEND_FRAME = false;

void Timer_Callback_100ms(void){
    ADCC_DischargeSampleCapacitor();   //Discharge capacitor voltage by connecting the VSS channel
    Data_Streamer.adcResult = ADCC_GetSingleConversion(channel_ANC3); //Get the conversion result
    Data_Streamer.adcSampleCount++;
    LED_Toggle();
    SEND_FRAME = true;
}

int main(void)
{
    SYSTEM_Initialize();
    
    Data_Streamer.adcSampleCount = 0;
    Data_Streamer.adcResult = 0;
    
    Timer->TimeoutCallbackRegister(Timer_Callback_100ms);
    
    INTERRUPT_GlobalInterruptEnable();

    while(1)
    {
        if(SEND_FRAME){
            WriteFrame();
            SEND_FRAME = false;
        }
    }
}

A change (above a set threshold) in the ADC result between successive conversions, represents a "spike". When a spike is detected, an callback updates the adcResult_lastSpike and adcSpikeCount variables.

Tested using PIC18F16Q41 CNANO board and potentiometer. When quickly turning the potentiometer a spike is detected.

After configuring the components as described above, click 'Generate' to generate the code. Then add the following code snippets to your application:

D,1,1,adcResult
D,1,1,adcResult_lastSpike
B,1,1,adcSpikeCount

#include "mcc_generated_files/system/system.h"
const struct TMR_INTERFACE *Timer = &Timer0;
volatile bool SEND_FRAME = false;

void ADCC_Callback_SpikeThreashold(void){
    Data_Streamer.adcResult_lastSpike = ADCC_GetConversionResult();
    Data_Streamer.adcSpikeCount++;
    LED_Toggle();
    DebugIO_Toggle();
    SEND_FRAME = true;
}

void Timer_Callback_100ms(void){
    ADCC_DischargeSampleCapacitor();         //Discharge capacitor voltage by connecting the VSS channel
    Data_Streamer.adcResult =  ADCC_GetSingleConversion(channel_ANC3); //Replace with suitable analog input - consulting your schematic 
    FRAME_SEND = true;
}

int main(void)
{
    SYSTEM_Initialize();
    
    Data_Streamer.adcSpikeCount = 0;
    Data_Streamer.adcResult_lastSpike = 0;
    Data_Streamer.adcResult = 0;

    Timer->TimeoutCallbackRegister(Timer_Callback_100ms);
    ADCC_SetADTIInterruptHandler(ADCC_Callback_SpikeThreashold);
    INTERRUPT_GlobalInterruptEnable();

    while(1)
    {
        if(SEND_FRAME){
            WriteFrame();
            SEND_FRAME = false;
        }
    }
}

Observe the change in sensitivity with the following settings...