STM32F207 - SPI2 Master

[Elektroniker (Gast)]

Hallo, ich möchte mit dem STM32F207 Mikrocontroller die SPI 
Schnittstelle 2 als Master verwenden. Hierfür habe ich zunächst die SPI 
Schnittstelle 2 konfiguriert:

/* SPIx Communication boards Interface */
#define SPIx                           SPI2
#define SPIx_CLK                       RCC_APB1Periph_SPI2
#define SPIx_CLK_INIT                  RCC_APB1PeriphClockCmd
#define SPIx_IRQn                      SPI2_IRQn
#define SPIx_IRQHANDLER                SPI2_IRQHandler

#define SPIx_SCK_PIN                   GPIO_Pin_1
#define SPIx_SCK_GPIO_PORT             GPIOI
#define SPIx_SCK_GPIO_CLK              RCC_AHB1Periph_GPIOI
#define SPIx_SCK_SOURCE                GPIO_PinSource1
#define SPIx_SCK_AF                    GPIO_AF_SPI2

#define SPIx_MISO_PIN                  GPIO_Pin_2
#define SPIx_MISO_GPIO_PORT            GPIOI
#define SPIx_MISO_GPIO_CLK             RCC_AHB1Periph_GPIOI
#define SPIx_MISO_SOURCE               GPIO_PinSource2
#define SPIx_MISO_AF                   GPIO_AF_SPI2

#define SPIx_MOSI_PIN                  GPIO_Pin_3
#define SPIx_MOSI_GPIO_PORT            GPIOI
#define SPIx_MOSI_GPIO_CLK             RCC_AHB1Periph_GPIOI
#define SPIx_MOSI_SOURCE               GPIO_PinSource3
#define SPIx_MOSI_AF                   GPIO_AF_SPI2

#define TXBUFFERSIZE   (countof(TxBuffer) - 1)
#define RXBUFFERSIZE   TXBUFFERSIZE


GPIO_InitTypeDef GPIO_InitStructure;
SPI_InitTypeDef SPI_InitStructure;

static void SPI_Config(void);
void SPIx_IRQHANDLER(void);
uint8_t GetVar_NbrOfData(void);

uint8_t TxBuffer[];
__IO uint8_t Counter = 0x00;
__IO uint32_t TimeOut;

__IO uint8_t Tx_Idx = 0x00;
__IO uint8_t CmdStatus = 0x00;
__IO uint8_t NumberOfByte = 0x01;

int  TimeStep100ms = 100;
int  TimeStep200ms = 200;
int  TimeStep500ms = 500;
int  NextTime = 0;

void main (void)
{
/* SPI configuration ------------------------------------------------------*/
  SPI_Config();
  
  /* Initializes the SPI communication */
  SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
  SPI_Init(SPIx, &SPI_InitStructure);
  
  /* The Data transfer is performed in the SPI interrupt routine */
  /* Enable the SPI peripheral */
  SPI_Cmd(SPIx, ENABLE);

  while (1)
  {
      STM_EVAL_LEDToggle(LED2);
      
      /* Enable the Tx buffer empty interrupt */
      SPI_I2S_ITConfig(SPIx, SPI_I2S_IT_TXE, ENABLE);
            
      /* Waiting the end of Data transfer */
      while (Tx_Idx < GetVar_NbrOfData())
      {
      }   
      delay(1000);
  }
}

void SPIx_IRQHANDLER(void)
{
  /* SPI in Master Tramitter mode--------------------------------------- */
  if (SPI_I2S_GetITStatus(SPIx, SPI_I2S_IT_TXE) == SET)
  {
    if (Tx_Idx < GetVar_NbrOfData())
    {
      /* Send Transaction data */
      SPI_I2S_SendData(SPIx, TxBuffer[Tx_Idx++]);
    }
    else
    {
      /* Disable the Tx buffer empty interrupt */
      SPI_I2S_ITConfig(SPIx, SPI_I2S_IT_TXE, DISABLE);
    }
  }
}

uint8_t GetVar_NbrOfData(void)
{
  return NumberOfByte;
}

static void SPI_Config(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;

  /* Enable the SPI clock */
  SPIx_CLK_INIT(SPIx_CLK, ENABLE);

  /* Enable GPIO clocks */
  RCC_AHB1PeriphClockCmd(SPIx_SCK_GPIO_CLK | SPIx_MISO_GPIO_CLK | SPIx_MOSI_GPIO_CLK, ENABLE);

  /* Connect SPI pins to AF5 */  
  GPIO_PinAFConfig(SPIx_SCK_GPIO_PORT, SPIx_SCK_SOURCE, SPIx_SCK_AF);
  GPIO_PinAFConfig(SPIx_MOSI_GPIO_PORT, SPIx_MOSI_SOURCE, SPIx_MOSI_AF);

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_DOWN;

  /* SPI SCK pin configuration */
  GPIO_InitStructure.GPIO_Pin = SPIx_SCK_PIN;
  GPIO_Init(SPIx_SCK_GPIO_PORT, &GPIO_InitStructure);

  /* SPI  MOSI pin configuration */
  GPIO_InitStructure.GPIO_Pin =  SPIx_MOSI_PIN;
  GPIO_Init(SPIx_MOSI_GPIO_PORT, &GPIO_InitStructure);
 
  /* SPI configuration -------------------------------------------------------*/
  SPI_I2S_DeInit(SPIx);
  SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
  SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
  SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
  SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
  SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
  SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_2;
  SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
  SPI_InitStructure.SPI_CRCPolynomial = 7;
  
  /* Configure the Priority Group to 1 bit */                
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
  
  /* Configure the SPI interrupt priority */
  NVIC_InitStructure.NVIC_IRQChannel = SPIx_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}

Ich möchte zyklisch Daten via SPI senden. Allerdings kann ich kein 
Clocksignal sowie am SPI Output (MOSI) Signale messen. Wo könnte da das 
Problem liegen ? Müsste zuvor am Master ein Slave Teilnehmer am SPI Bus 
angehängt werden ?

[holger (Gast)]

>Wo könnte da das Problem liegen ?

Tx_Idx wird nirgendwo wieder auf 0 gesetzt.

[Elektroniker (Gast)]

Hi holger,

danke. Habs dann auch bemerkt. Nun funktioniert das Senden.

Ich habe bezüglich SPI noch zwei Fragen.

1) Wie wird auf dem SPI Master die Empfängerfunktionalität implementiert 
?

2) Kann für den SPI Master der DMA für das Senden und auch für das 
Empfangen von Nachrichten verwendet werden ?