SPI_I2S_ReceiveData 总是 returns 0xff 或 0x00

Question

我想创建固件到 stm32f4 发现，当电路板移动时它会闪烁。但是 SPI_I2S_ReceiveData 总是 returns 0xff 或 0x00。我认为问题出在我的 SPI 初始化中，但我不知道它到底在哪里。

这是我的代码。

#include <stm32f4xx.h>
#include <stm32f4xx_rcc.h>
#include <stm32f4xx_gpio.h>
#include <stm32f4xx_spi.h>
#include <stm32f4xx_i2c.h>

void InitLEDs(void);

void InitSPI(void);

void Delay(int iTicks);

void DiodeFlash(void);

unsigned short ReadACCELEROMETER(void);

unsigned char WriteSPI(unsigned char cbData);

int main(void)
{
    unsigned short cbPrevRead = 0;
    unsigned short cbCurrentRead = 0;

    InitLEDs();
    InitSPI();

    while(1)
    {
        cbCurrentRead = ReadACCELEROMETER();

        if (cbCurrentRead != cbPrevRead)
        {
            DiodeFlash();

            cbPrevRead = cbCurrentRead;
        }
    }
}


void InitLEDs(void)
{
    GPIO_InitTypeDef PortD;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);

    PortD.GPIO_Mode = GPIO_Mode_OUT;
    PortD.GPIO_OType = GPIO_OType_PP;
    PortD.GPIO_PuPd = GPIO_PuPd_NOPULL;
    PortD.GPIO_Speed = GPIO_Speed_100MHz;
    PortD.GPIO_Pin = GPIO_Pin_12 | GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;

    GPIO_Init(GPIOD, &PortD);
}


void InitSPI(void)
{
    GPIO_InitTypeDef PortA;
    GPIO_InitTypeDef PortE;

    SPI_InitTypeDef SPI1Conf;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);

    PortA.GPIO_Mode = GPIO_Mode_AF;
    PortA.GPIO_OType = GPIO_OType_PP;
    PortA.GPIO_Speed = GPIO_Speed_50MHz;
    PortA.GPIO_PuPd = GPIO_PuPd_NOPULL;
    PortA.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;

    GPIO_Init(GPIOA, &PortA);

    GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_SPI1);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1);


    PortE.GPIO_Mode = GPIO_Mode_OUT;
    PortE.GPIO_OType = GPIO_OType_PP;
    PortE.GPIO_Speed = GPIO_Speed_50MHz;
    PortE.GPIO_PuPd = GPIO_PuPd_NOPULL;
    PortE.GPIO_Pin = GPIO_Pin_3;

    GPIO_Init(GPIOE, &PortE);

    GPIOE->ODR = 0x0008; // Disable CS

    SPI1Conf.SPI_DataSize = SPI_DataSize_8b;
    SPI1Conf.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_64;
    SPI1Conf.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
    SPI1Conf.SPI_FirstBit = SPI_FirstBit_MSB; // ACCELEROMETER PROTOCOL
    SPI1Conf.SPI_Mode = SPI_Mode_Master;
    SPI1Conf.SPI_CPHA = SPI_CPHA_2Edge;
    SPI1Conf.SPI_CPOL = SPI_CPOL_High;
    SPI1Conf.SPI_CRCPolynomial = 7;
    SPI1Conf.SPI_NSS = SPI_NSS_Soft;
    SPI_Init(SPI1, &SPI1Conf);
    SPI_Cmd(SPI1, ENABLE);

    WriteSPI(0x23); WriteSPI(0xc9);
    WriteSPI(0x20); WriteSPI(0x97);
    WriteSPI(0x24); WriteSPI(0x00);

    WriteSPI(0x10); WriteSPI(0x00);
    WriteSPI(0x11); WriteSPI(0x00);
    WriteSPI(0x12); WriteSPI(0x00);
}


void Delay(int iTicks)
{
    while ((iTicks--) > 0);
}


void DiodeFlash(void)
{
    GPIO_Write(GPIOD, 1UL << 12);
    Delay(100000);
    GPIO_Write(GPIOD, 1UL << 13);
    Delay(100000);
    GPIO_Write(GPIOD, 1UL << 14);
    Delay(100000);
    GPIO_Write(GPIOD, 1UL << 15);
    Delay(100000);
    GPIO_Write(GPIOD, 0x0000);
}

unsigned short ReadACCELEROMETER(void)
{
    unsigned short nAxisX = 0x0000;
    unsigned short nAxisY = 0x0000;
    unsigned short nAxisZ = 0x0000;

    unsigned char cbAddress = 0x80;

    //**********************************************************
    // Forming X Value
    WriteSPI(cbAddress | 0x0f);
    nAxisX |= WriteSPI(0x00);

    WriteSPI(cbAddress | 0x2A);
    nAxisX |= WriteSPI(0x00) << 8;

    //**********************************************************
    // Forming Y Value
    WriteSPI(cbAddress | 0x2B);
    nAxisX |= WriteSPI(0x00);

    WriteSPI(cbAddress | 0x2C);
    nAxisX |= WriteSPI(0x00) << 8;

    //**********************************************************
    // Forming Z Value
    WriteSPI(cbAddress | 0x2D);
    nAxisX |= WriteSPI(0x00);

    WriteSPI(cbAddress | 0x2E);
    nAxisX |= WriteSPI(0x00) << 8;

    return nAxisX ^ nAxisY ^ nAxisZ;
}

unsigned char WriteSPI(unsigned char cbData)
{
    unsigned char cbResult = 0x00;

    GPIOE->ODR = 0x0000; // Enable CS

    // Wait for ready status
    while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_BSY) == SET);

    SPI_I2S_SendData(SPI1, cbData);

    // Wait for ready status
    while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_BSY) == SET);

    cbResult = SPI_I2S_ReceiveData(SPI1);

    GPIOE->ODR = 0x0008; // Disable CS

    return cbResult;
}

Answer 1

首先，您没有指定加速度计。我猜是ST LISxx.
在这种情况下，加速度计的数据传输不正确。

正确的写入顺序：
- 激活芯片选择
- 写寄存器号
- 写入寄存器值
- 停用芯片选择
使用相似的顺序读取每个寄存器。

接下来，ST 不推荐您的算法用于低级 SPI 传输：

Do not use the BSY flag to handle each data transmission or reception. It is better to use the TXE and RXNE flags instead

（参见参考手册）。简单地使用

SPIx->DR = out;  
while (!(SPIx->SR & SPI_SR_RXNE)) ;  
return SPIx->DR;

此外，我正在使用 LIS3DH，CPOL=0 & CPHA = 0 SPI 设置（我不知道，它如何与你的 CPOL=1，CPHA=1 一起工作）。

提示：要检查 SPI 通信，请尝试读取 WHO_AM_I 寄存器 - 它始终处于启用状态并且始终具有已知值。

Answer 2

因为你写了寄存器的地址，取消选择你的设备后，所以写的地址被清理掉了。在这种情况下，您必须这样做。

unsigned char WriteSPI(unsigned char cbData)
{
    unsigned char cbResult = 0x00;

    // Wait for ready status
    while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_BSY) == SET);

    SPI_I2S_SendData(SPI1, cbData);

    // Wait for ready status
    while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_BSY) == SET);

    cbResult = SPI_I2S_ReceiveData(SPI1);

    return cbResult;
}


unsigned char WriteReg(unsigned char cbAddress, unsigned char cbData)
{
    unsigned char cbResult = 0x00;

    GPIOE->ODR = 0x0000; // select device
    WriteSPI(cbAddress);
    cbResult = WriteSPI(cbData);
    GPIOE->ODR = 0x0008; // deselect device

    return cbResult;
}

unsigned char ReadReg(unsigned char cbAddress)
{
    unsigned char cbResult = 0x00;

    GPIOE->ODR = 0x0000; // select device
    WriteSPI(cbAddress);
    cbResult = WriteSPI(0x00);
    GPIOE->ODR = 0x0008; // deselect device

    return cbResult;
}

Answer 3

你的SPI初始化没有问题。主要错误是写寄存器地址。在读取寄存器值之前，您不得取消选择设备，而必须执行写地址 - 批量读取值。意思是

Select 设备。
写入寄存器地址。
读取寄存器值。
取消选择设备。

SPI_I2S_ReceiveData 总是 returns 0xff 或 0x00

SPI_I2S_ReceiveData always returns 0xff or 0x00

c

embedded

stm32