AD7683 + STM32F407 + SPI

Question

我有stm32f407discovery和ADC AD7683

我嘗試讀取一個16位的採樣值作爲3×8位的SPI值和使用一個比特移位，但我只在所有接收「1」 3 spi值。

有誰知道如何解決這個問題，或者問題出在哪裏？

#define CS_LOW GPIOA->BSRRH = GPIO_BSRR_BS_15; 
#define CS_HIGH GPIOA->BSRRL = GPIO_BSRR_BS_15; 

uint8_t DataHigh = 0; 
uint8_t DataMid = 0; 
uint8_t DataLow = 0; 
uint16_t result = 0; 
uint16_t res = 0; 
////////////////////////////////////////////////////////// 
void SPI_in() 
{ 
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE); 
    GPIO_InitTypeDef GPIO_InitStructure; 
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11; 
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; 
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; 
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; 
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; 
    GPIO_Init(GPIOC, &GPIO_InitStructure); 

    GPIO_PinAFConfig(GPIOC, GPIO_PinSource10, GPIO_AF_SPI3); 
    GPIO_PinAFConfig(GPIOC, GPIO_PinSource11, GPIO_AF_SPI3); 
    //GPIO_PinAFConfig(GPIOC, GPIO_PinSource12, GPIO_AF_SPI3); 

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE); 
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_15; // cs 
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT; 
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; 
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; 
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; 
    GPIO_Init(GPIOA, &GPIO_InitStructure); 

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI3, ENABLE); 
    SPI_InitTypeDef SPI_InitStructure; 
    SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_128; 
    SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge; 
    SPI_InitStructure.SPI_CPOL = SPI_CPOL_High; 
    SPI_InitStructure.SPI_CRCPolynomial = 7; 
    SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b; 
    SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_RxOnly; 
    SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB; 
    SPI_InitStructure.SPI_Mode = SPI_Mode_Master; 
    SPI_InitStructure.SPI_NSS = SPI_NSS_Soft; 

    SPI_Init(SPI3, &SPI_InitStructure); 
    //SPI_SSOutputCmd(SPI3, ENABLE); 
    SPI_Cmd(SPI3, ENABLE); 
    SPI_NSSInternalSoftwareConfig(SPI3, SPI_NSSInternalSoft_Set); 

    CS_HIGH; 
} 
void TIM_in() 
{ 
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE); 
    TIM_TimeBaseInitTypeDef TIM_Init; 
    TIM_Init.TIM_ClockDivision = TIM_CKD_DIV1; 
    TIM_Init.TIM_CounterMode = TIM_CounterMode_Up; 
    TIM_Init.TIM_Period = 10; 
    TIM_Init.TIM_Prescaler = 2000-1; 
    TIM_TimeBaseInit(TIM2, &TIM_Init); 
    NVIC_EnableIRQ(TIM2_IRQn); 
    TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE); 
    TIM_Cmd(TIM2, ENABLE); 
} 
/////////////////////////////////////////////////////////// 
void TIM2_IRQHandler(void) 
{ 
    if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET) 
    { 
     CS_LOW; 
     //while (SPI_I2S_GetFlagStatus(SPI3, SPI_I2S_FLAG_BSY) == SET) {} 
     if (SPI_I2S_GetFlagStatus(SPI3, SPI_I2S_FLAG_RXNE) == SET) 
     { 
      DataHigh = SPI_I2S_ReceiveData(SPI3); 
      //while (SPI_I2S_GetFlagStatus(SPI3, SPI_I2S_FLAG_RXNE) == SET) {} 
      DataMid = SPI_I2S_ReceiveData(SPI3); 
      //while (SPI_I2S_GetFlagStatus(SPI3, SPI_I2S_FLAG_RXNE) == SET) {} 
      DataLow = SPI_I2S_ReceiveData(SPI3); 
     } 
     CS_HIGH; 
     result = (DataHigh << 14) | (DataMid << 6) | (DataLow >> 2); 
     res = result >> 4; 
     DAC->DHR12R1 = res; 
     TIM_ClearITPendingBit(TIM2, TIM_IT_Update); 
    } 
} 

/////////////////////////////////////////////////////////// 
void DAC_in() 
{ 
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE); 
    GPIO_InitTypeDef GPIO_InitDAC; 
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE); 
    GPIO_InitDAC.GPIO_Pin = GPIO_Pin_4; 
    GPIO_InitDAC.GPIO_Mode = GPIO_Mode_AIN; 
    GPIO_Init(GPIOA, &GPIO_InitDAC); 

    DAC_InitTypeDef DAC_In; 
    DAC_In.DAC_LFSRUnmask_TriangleAmplitude = DAC_LFSRUnmask_Bit0; 
    DAC_In.DAC_OutputBuffer = DAC_OutputBuffer_Enable; 
    DAC_In.DAC_Trigger = DAC_Trigger_None; 
    DAC_In.DAC_WaveGeneration = DAC_WaveGeneration_None; 

    DAC_Init(DAC_Channel_1, &DAC_In); 
    DAC_Cmd(DAC_Channel_1, ENABLE); 
} 

int main(void) 
{ 
    SPI_in(); 
    TIM_in(); 
    DAC_in(); 
    while(1) 
    { 
    } 
} 

Answer 1

的SPI_I2S_ReceiveData（SPI3）函數是不會阻止並且僅返回當前存儲在SPI3數據寄存器中的值。您需要將一個字節加載到SPI3數據寄存器以啓動SPI外設發送該字節，然後您需要等待，直到RXNE標誌置位，然後您將獲得如下所示的數據：

CS_LOW; 
SPI_I2S_SendData(SPI3, 0xFF); //Send dummy byte to start SPI transaction 
while(SPI_I2S_GetFlagStatus(SPI3, SPI_I2S_FLAG_RXNE) == RESET); 
DataHigh = SPI_I2S_ReceiveData(SPI3); 
while(SPI_I2S_GetFlagStatus(SPI3, SPI_I2S_FLAG_RXNE) == RESET); 
DataMid = SPI_I2S_ReceiveData(SPI3); 
while(SPI_I2S_GetFlagStatus(SPI3, SPI_I2S_FLAG_RXNE) == RESET); 
DataLow = SPI_I2S_ReceiveData(SPI3); 
CS_HIGH; 

//Do stuff with data