SPI_I2S_ReceiveData始终返回0xff或0x00 [英] SPI_I2S_ReceiveData always returns 0xff or 0x00

问题描述

我想创建固件到stm32f4，以便在主板移动时使指示灯闪烁。但是 SPI_I2S_ReceiveData 始终返回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。

I want to create firmware to stm32f4 discovery wich flashes the lights, when the board moves. But SPI_I2S_ReceiveData always returns 0xff or 0x00. I think the problem is in my SPI initialization but I do not know where exactly it is.

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;
}

推荐答案

首先，您不需要指定您的加速度计。我猜是ST LISxx。

在这种情况下，向加速度计的数据传输不正确。

First, you don't specify your accelerometer. I can guess, that it is ST LISxx.
In this case, there is incorrect data transfer to accelerometer.

正确的写入顺序：

-激活chipselect

-写寄存器编号

-写寄存器值

-禁用chipselect

使用类似的顺序读取每个寄存器。

Correct write sequence:
- activate chipselect
- write register number
- write register value
- deactivate chipselect
Use similar sequence to read each register.

接下来，ST不建议您使用算法进行低级SPI传输：

Next, ST not recommend your algo for low-level SPI transfer:

请勿使用BSY标志来处理每个数据发送或接收。最好改用TXE和RXNE标志

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

（请参阅参考手册）。只需使用

(see Reference manual). Use simply

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

此外，我正在使用CPOL = 0& CPHA = 0 SPI设置（我不知道，它将如何与您的CPOL = 1，CPHA = 1一起工作）。

Also, i am working with LIS3DH with CPOL=0 & CPHA = 0 SPI settings (i don't know, how it will work with your CPOL=1, CPHA=1).

提示：要检查SPI通信，请尝试读取WHO_AM_I寄存器-已启用awally，并且始终具有已知值。

Hint: to check SPI communication, try to read WHO_AM_I register - it is alawys enabled and always have known value.

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