MSPM0G3507应用之ADC数据通过I2C接口进行传输

例程位于官方SDK下面，如下图所示：

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#include "ti_msp_dl_config.h"



/* Maximum size of TX packet */

#define I2C_TX_MAX_PACKET_SIZE (16)



/* Maximum size of RX packet */

#define I2C_RX_MAX_PACKET_SIZE (16)



/* Commands for the ADC sampling */

#define SAMPLE_ADC (0x01)

#define SEND_RESULTS (0x02)

#define SAMPLE_SEND_RESULTS (0x03)



/* Data sent to Controller in response to Read transfer, default set to 0xAA */

uint8_t gTxPacket[I2C_TX_MAX_PACKET_SIZE] = {0xAA};



/* Counters for TX length and bytes sent */

uint32_t gTxLen, gTxCount;



/* Data received from Controller during a Write transfer */

uint8_t gRxPacket[I2C_RX_MAX_PACKET_SIZE];



/* Counters for TX length and bytes sent */

uint32_t gRxLen, gRxCount, gCommandCount;



/* Boolean to know when a stop command was issued */

bool gStopReceived = false;



/* ADC variables:

 * gADCResult is the adc result taken from the Memory Register

 * NumberOfADCSamples is the count of total ADC samples to keep track for the gTxResult buffer

 */



uint16_t gADCResult;

uint8_t gNumberOfADCSamples = 0;

bool gCheckADC = false;



/* Process Command will take the command from the I2C Rx and parse which command is to be issued */

void processCommand(uint8_t cmd);



/* ADC Process will start the ADC and separate the ADC result into 8 bits to place into the Tx Packet buffer. */

void ADCProcess();



int main(void)

{

    SYSCFG_DL_init();



    /* Set LED to indicate start of transfer */

    DL_GPIO_setPins(GPIO_LEDS_PORT, GPIO_LEDS_USER_LED_1_PIN);



   /* Reset variables for the Tx, these are used in the I2C ISR */

    gTxCount = 0;

    gTxLen   = 0;

    DL_I2C_enableInterrupt(I2C_INST, DL_I2C_INTERRUPT_TARGET_TXFIFO_TRIGGER);



    /* Initialize variables to receive data inside RX ISR */

    gRxCount = 0;

    gRxLen   = I2C_RX_MAX_PACKET_SIZE;



    NVIC_EnableIRQ(I2C_INST_INT_IRQN);

    NVIC_EnableIRQ(ADC12_0_INST_INT_IRQN);





    while (1)

    {

        /* Sleep until the stop command is given from the I2C Controller */

        while(gStopReceived == false)

            __WFE();

        gStopReceived = false;



        /* Process given commands */

        for(uint16_t i = 0; i < gCommandCount; i++){

            processCommand(gRxPacket[i]);

        }

        gCommandCount = 0;

    }

}



/* Process the command given */

void processCommand(uint8_t cmd){



    switch(cmd){

        /* Sample the ADC */

        case SAMPLE_ADC:

            ADCProcess();

            break;

        /* Add 2 to the Tx Length, this equates to one more full result added to the TX transmission */

        case SEND_RESULTS:

            gTxLen += 2;

            break;

        /* Sample the ADC and increment the Tx Length. */

        case SAMPLE_SEND_RESULTS:

            ADCProcess();

            gTxLen += 2;

            break;

        default:

            break;

    }

}



/* Start the ADC process of sampling and storing into the TxPacket Buffer */

void ADCProcess(){



    /* Start the ADC Sampling */



    DL_ADC12_startConversion(ADC12_0_INST);



    /* Sleep until the ADC sampling and conversion is finished, then reset the boolean */

    while(gCheckADC == false){

        __WFI();

    }

    gCheckADC = false;



    /* Get the ADC result and place the upper byte and lower byte into the TxPacket, upper byte first */

    gADCResult = DL_ADC12_getMemResult(ADC12_0_INST, DL_ADC12_MEM_IDX_0);

    gTxPacket[gNumberOfADCSamples*2] = (uint8_t)((gADCResult >> 8) & 0xFF);

    gTxPacket[gNumberOfADCSamples*2 + 1] = (uint8_t)(gADCResult & 0xFF);



    /* Make sure the number of ADC samples does not go over the TxPacket size, if it does next sample will overwrite */

    gNumberOfADCSamples++;

    if(gNumberOfADCSamples*2 + 1 > I2C_TX_MAX_PACKET_SIZE)

    {

        gNumberOfADCSamples = 0;

    }

    DL_ADC12_enableConversions(ADC12_0_INST);



}





void ADC12_0_INST_IRQHandler(void) {

  switch (DL_ADC12_getPendingInterrupt(ADC12_0_INST)) {

  case DL_ADC12_IIDX_MEM0_RESULT_LOADED:

    gCheckADC = true;

    break;

  default:

    break;

  }

}





void I2C_INST_IRQHandler(void)

{

    static bool commandReceived = false;



    switch (DL_I2C_getPendingInterrupt(I2C_INST)) {

        case DL_I2C_IIDX_TARGET_START:

            /* Initialize RX or TX after Start condition is received */

            gTxCount = 0;

            gRxCount = 0;

            commandReceived   = false;

            /* Flush TX FIFO to refill it */

            DL_I2C_flushTargetTXFIFO(I2C_INST);

            break;

        case DL_I2C_IIDX_TARGET_RXFIFO_TRIGGER:

            /* Store received commands in buffer */

            commandReceived = true;

            while (DL_I2C_isTargetRXFIFOEmpty(I2C_INST) != true) {

                if (gRxCount < gRxLen) {

                    gRxPacket[gRxCount++] = DL_I2C_receiveTargetData(I2C_INST);

                } else {

                    /* Prevent overflow and just ignore data */

                    DL_I2C_receiveTargetData(I2C_INST);

                }

            }

            break;

        case DL_I2C_IIDX_TARGET_TXFIFO_TRIGGER:

            /* Fill TX FIFO with ADC Results */

            if (gTxCount < gTxLen) {

                gTxCount += DL_I2C_fillTargetTXFIFO(

                    I2C_INST, &gTxPacket[gTxCount], (gTxLen - gTxCount));

            } else {

                /*

                 * Fill FIFO with 0xAA if more data is requested than

                 * expected gTxLen

                 */

                while (DL_I2C_transmitTargetDataCheck(I2C_INST, 0xAA) != false)

                    ;

            }

            break;

        case DL_I2C_IIDX_TARGET_STOP:

            /* If commands were received, set the command count to RxCount and reset fifo */

            if (commandReceived == true) {

                gCommandCount = gRxCount;

                commandReceived = false;

                DL_I2C_flushTargetTXFIFO(I2C_INST);

            }



            /* Set Stop Received to true to allow the main loop to proceed */

            gStopReceived = true;

            /* Toggle LED to indicate successful RX or TX */

            DL_GPIO_togglePins(GPIO_LEDS_PORT, GPIO_LEDS_USER_LED_1_PIN);

            break;

        default:

            break;

    }

}