SPI raspberry pi (master) & arduino due (slave)

Question

我正在尝试与 SPI 通信 raspi 和到期。 Raspi 是主人，due 是奴隶。 我可以毫无问题地通过 SPI 从 raspi 发送字节到到期。 但是我在 DUE 方面需要的是，当我收到来自 Raspi 的数据时，我会从 DUE 向 Raspi 发送一个新数据。 这是我的代码；

Raspi QT 接线 pi（主）

#include <wiringPiSPI.h>
#include <QDebug>
#define SPI_CHANNEL 0
#define SPI_CLOCK_SPEED 500000

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    int fd = wiringPiSPISetupMode(SPI_CHANNEL, SPI_CLOCK_SPEED, 0); // Starting SPI
    if (fd == -1) {
        qDebug() << "Failed to init SPI communication.\n";
        return -1;
    }
    qDebug() << "SPI communication successfully setup.\n";


    unsigned char buf[2] = { 1, 2 }; // Char for sending to DUE
    wiringPiSPIDataRW(SPI_CHANNEL, buf, 2); // Sending and receiving data
    qDebug() << "Data returned: " << buf[0] << buf[1] << "\n";
    return a.exec();
}

Arduino DUE 代码（从属）

void setup() {
Serial.begin(250000);
//SPI serial recieve
REG_PMC_PCER0 |= PMC_PCER0_PID24;      // Power up SPI clock
REG_SPI0_WPMR = 0<<SPI_WPMR_WPEN;   //Unlock user interface for SPI

//Instance SPI0, MISO: PA25, (MISO), MOSI: PA26, (MOSI), SCLK: PA27, (SCLK), NSS: PA28, (NPCS0)
REG_PIOA_ABSR |= PIO_ABSR_P25;    // Transfer Pin control from PIO to SPI
REG_PIOA_PDR |= PIO_PDR_P25;        // Set MISO pin to an output

REG_PIOA_ABSR |= PIO_ABSR_P26;    // Transfer Pin control from PIO to SPI
REG_PIOA_PDR |= 0<<PIO_PDR_P26;  // Set MOSI pin to an input

REG_PIOA_ABSR |= PIO_ABSR_P27;     // Transfer Pin control from PIO to SPI
REG_PIOA_PDR |= 0<<PIO_PDR_P27;   // Set SCLK pin to an input

REG_PIOA_ABSR |= PIO_ABSR_P28;     // Transfer Pin control from PIO to SPI
REG_PIOA_PDR |= 0<<PIO_PDR_P28;   // Set NSS pin to an input

REG_SPI0_CR = 1;   // Enable SPI
REG_SPI0_MR = 0;   // Slave mode
// Receive Data Register Full Interrupt
SPI0->SPI_IER = SPI_IER_RDRF;
NVIC_EnableIRQ(SPI0_IRQn);

SPI0->SPI_CSR[0] = SPI_CSR_NCPHA|SPI_CSR_BITS_8_BIT;
}

void SPI0_Handler()
{    
  byte c = SPI0->SPI_RDR;
  SPI0->SPI_TDR = c;
}

使用这些代码，我可以成功地将字符从 Raspberry 发送到 DUE，但只能从 DUE 接收“0 0”。 但是如果我将 Raspberry pi 上的 MOSI 和 MISO 引脚连接在一起，我将无法成功接收/返回“1 2”

编辑： 我用 arduino MEGA 更改了 arduino DUE，并在 gammon 上使用了“SLAVE”草图...GAMMON SLAVE SKETCH 当然，覆盆子方面没有任何变化，一切都成功了。 所以问题出在 DUE 方面....

Answer 1

我检查了到期的数据表。 寄存器有一些错误。你可以试试这个：

void setup() {
    Serial.begin(115200);
    while(!Serial);

    //SPI serial recieve
    REG_PMC_PCER0 |= PMC_PCER0_PID24;       // Power up SPI clock
    REG_SPI0_WPMR = 0<<SPI_WPMR_WPEN;       //Unlock user interface for SPI

    //Instance SPI0, MISO: PA25, (MISO), MOSI: PA26, (MOSI), SCLK: PA27, (SCLK), NSS: PA28, (NPCS0)
    REG_PIOA_ABSR &= ~PIO_ABSR_P25;         // Transfer Pin control from PIO to SPI
    REG_PIOA_PDR |= PIO_PDR_P25;            // disable pio to control this pin (MOSI)

    REG_PIOA_ABSR &= ~PIO_ABSR_P26;         // Transfer Pin control from PIO to SPI
    REG_PIOA_PDR |= PIO_PDR_P26;            // disable pio to control this pin (MOSI)

    REG_PIOA_ABSR &= ~PIO_ABSR_P27;         // Transfer Pin control from PIO to SPI
    REG_PIOA_PDR |= PIO_PDR_P27;            // disable pio to control this pin (SCLK)

    REG_PIOA_ABSR &= ~PIO_ABSR_P28;         // Transfer Pin control from PIO to SPI
    REG_PIOA_PDR |= PIO_PDR_P28;            //disable pio to control this pin (NSS)

    REG_SPI0_CR = 1;                        // Enable SPI
    REG_SPI0_MR = 0;                        // Slave mode

    SPI0->SPI_IER = SPI_IER_RDRF;           //Receive Data Register Full Interrupt
    NVIC_EnableIRQ(SPI0_IRQn);

    SPI0->SPI_CSR[0] = SPI_CSR_NCPHA|SPI_CSR_BITS_8_BIT;    // Shift on falling edge and transfer 8 bits.
    Serial.println("START");
}

bool flag=false;
uint16_t DataReceived;
void SPI0_Handler()
{
    uint32_t status = SPI0->SPI_SR;
    if (status & SPI_SR_RDRF){
        DataReceived = SPI0->SPI_RDR & SPI_RDR_RD_Msk;
        flag=true;
    }
    if (status & SPI_SR_TDRE) {
        SPI0->SPI_TDR = (uint16_t)DataReceived;
    }
}

void loop() {
    if(flag){
        flag=false;
        Serial.println(DataReceived);
    }
}