[参考译文] ADC128S102EVM：将 ADC128S102EVM 与 MSP-EXP430FR5969配合使用- ADC 输出不一致

https://e2e.ti.com/support/data-converters-group/data-converters/f/data-converters-forum/1004872/adc128s102evm-using-the-adc128s102evm-with-msp-exp430fr5969---the-adc-output-is-not-consistent

我在 调试模式下启动 MSP430FR5969 Launchpad 使用外部源在其中一个模拟输入(通常为缓冲输入3)上设置电压(<1.5V)。 通过 SPI 总线的读取电压正确。 我让它循环几次、然后更改同一输入上的输入电压(<1.5V) 、我仍然获得旧的电压读数。  或 在 SPI 位1446上获得固定值。 我正在使用 Launchpad FR5969和插入的 ADC128S102EVM。 我无法使 ADC EVM 作为通过跳线电缆连接的单独实体工作。  以下是我的代码(我知道我在 ISR 中做了很多工作-我的代码的最终版本将不会)：

#include "driverlib.h"

 
#define ADCVREF 2895 // ADC Vref - measured as 2.895V on the EVM

#define Port_4_nADC_CS                 (0x04)          //  P4.2. !CS for ADC128S102

 
volatile static int index = 0;

volatile unsigned short spiRxDataArr[8] = {0,0,0,0,0,0,0,0};

volatile unsigned char spiTxDataArr[] = {0x00, 0x08, 0x10, 0x18, 0x20,0x28, 0x30, 0x38, 0x00};

volatile static int msbLsbTX = 1;

volatile static int msbLsbRX = 1;

volatile static int firstFlag = 1;

volatile unsigned short adcmVoltage[8] = {0,0,0,0,0,0,0,0};

 

void main(void)

{

    //Stop watchdog timer

    WDT_A_hold(WDT_A_BASE);

 

    /*

     * Select Port 1

     * Set Pin 0 as output

     */

    GPIO_setAsOutputPin(

        GPIO_PORT_P1,

        GPIO_PIN0

    );

    /*

    * Select Port 1

    * Set Pin 0 to output Low.

    */

    GPIO_setOutputLowOnPin(

        GPIO_PORT_P1,

        GPIO_PIN0

    );

 

    //Set DCO frequency to 16 MHz DCO setting

    CS_setDCOFreq(CS_DCORSEL_1,CS_DCOFSEL_4);

    //Select DCO as the clock source for SMCLK with no frequency divider

    CS_initClockSignal(CS_SMCLK,CS_DCOCLK_SELECT,CS_CLOCK_DIVIDER_1);

     /*

    * Select Port 2

    * Set Pin 2 to input Secondary Module Function, (UCB0CLK).

    */

    GPIO_setAsPeripheralModuleFunctionInputPin(

        GPIO_PORT_P2,

        GPIO_PIN2,

        GPIO_SECONDARY_MODULE_FUNCTION

    );

 

    /*

    * Select Port 1

    * Set Pin 6, 7 to input Secondary Module Function, (UCB0TXD/UCB0SIMO, UCB0RXD/UCB0SOMI).

    */

    GPIO_setAsPeripheralModuleFunctionInputPin(

        GPIO_PORT_P1,

        GPIO_PIN6 + GPIO_PIN7,

        GPIO_SECONDARY_MODULE_FUNCTION

    );

 

    /*

    * Disable the GPIO power-on default high-impedance mode to activate

    * previously configured port settings

    */

    PMM_unlockLPM5();

 

    P4DIR |= 0x04;  //  Configure P4.2 (/ADC_CS) as an output.

 

    //Initialize Master

    EUSCI_B_SPI_initMasterParam param1 = {0};

    param1.selectClockSource = EUSCI_B_SPI_CLOCKSOURCE_SMCLK;

    param1.clockSourceFrequency = CS_getSMCLK();

    param1.desiredSpiClock = 8000000; // 8 MHz clock (min requirement for adc128s102)

    param1.msbFirst = EUSCI_B_SPI_MSB_FIRST;

    param1.clockPhase = EUSCI_B_SPI_PHASE_DATA_CHANGED_ONFIRST_CAPTURED_ON_NEXT;

    param1.clockPolarity = EUSCI_B_SPI_CLOCKPOLARITY_INACTIVITY_HIGH;

    param1.spiMode = EUSCI_B_SPI_3PIN;

    EUSCI_B_SPI_initMaster(EUSCI_B0_BASE, &param1);

 

    //Enable SPI module

    EUSCI_B_SPI_enable(EUSCI_B0_BASE);

    EUSCI_B_SPI_clearInterrupt(EUSCI_B0_BASE, EUSCI_B_SPI_RECEIVE_INTERRUPT);

    // Enable USCI_B0 RX interrupt

    EUSCI_B_SPI_enableInterrupt(EUSCI_B0_BASE, EUSCI_B_SPI_RECEIVE_INTERRUPT);

 

    //Wait for slave to initialize

    __delay_cycles(100);

 

    P4OUT |= Port_4_nADC_CS;  // /ADC_CS frames the SPI transmission.  Initialize here.

    __delay_cycles(2000);

    P4OUT &= ~Port_4_nADC_CS;

 

    //USCI_B0 TX buffer ready?

    while (!EUSCI_B_SPI_getInterruptStatus(EUSCI_B0_BASE, EUSCI_B_SPI_TRANSMIT_INTERRUPT)) ;

     //Transmit Data to slave (MSB) - Get the process started

    EUSCI_B_SPI_transmitData(EUSCI_B0_BASE, spiTxDataArr[index]);

    msbLsbTX = 0;

 

    __bis_SR_register(LPM0_bits + GIE);      // CPU off, enable interrupts

    __no_operation();                       // Remain in LPM0 */

}

 

 

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)

#pragma vector=USCI_B0_VECTOR

__interrupt

#elif defined(__GNUC__)

__attribute__((interrupt(USCI_B0_VECTOR)))

#endif

void USCI_B0_ISR (void)

{

    volatile unsigned char temp = 0x00; // need to get rid of this - easy to see data in debug

    switch (__even_in_range(UCB0IV, USCI_SPI_UCTXIFG))

    {

        // first 4 bits are zeros, then 12 bit data

        case USCI_SPI_UCRXIFG:      // UCRXIFG

            //USCI_B0 TX buffer ready?

            while (!EUSCI_B_SPI_getInterruptStatus(EUSCI_B0_BASE, EUSCI_B_SPI_TRANSMIT_INTERRUPT));

             if (firstFlag){ // skip collecting the first 16 bits - garbage

                if(!msbLsbRX){

                    firstFlag = 0;

                    msbLsbRX = 1;

                    index++;

                }

                else

                    msbLsbRX = 0;

            }

            else{

                if(msbLsbRX){//MSB

                    temp = EUSCI_B_SPI_receiveData(EUSCI_B0_BASE);

                    spiRxDataArr[index-1] = spiRxDataArr[index-1] | temp << 8;

                    msbLsbRX = 0;

                }

                else{//LSB

                    temp =  EUSCI_B_SPI_receiveData(EUSCI_B0_BASE);

                    spiRxDataArr[index-1] = spiRxDataArr[index-1] | temp;

                    // SPI bits * Vref (2895 mV)/4096

                    adcmVoltage[index-1] = (unsigned short) (((unsigned long)spiRxDataArr[index-1] * ADCVREF)>>12); // divide by 4096

                    msbLsbRX = 1;

                    index++;

                    if (index > 8)

                        index = 1;

                }

 

            }

             //Send next value

            if(!msbLsbTX){ //LSB

                EUSCI_B_SPI_transmitData(EUSCI_B0_BASE,0x00);

                msbLsbTX = 1;

                P4OUT |= Port_4_nADC_CS;

            }

            else{ //MSB

                P4OUT &= ~Port_4_nADC_CS;

                EUSCI_B_SPI_transmitData(EUSCI_B0_BASE,spiTxDataArr[index]);

                msbLsbTX = 0;

            }

 

            break;

        default:

            break;

    }

}