SPI 통신 (3)

SPI code

--------------------------------------------- header ---------------------------------------------

/* SPI header */

#define SPIy            SPI1

#define SPIy_GPIO       GPIOA

#define SPIy_SCKPin     GPIO_Pin_5

#define SPIy_MISOPin    GPIO_Pin_6

#define SPIy_MOSIPin    GPIO_Pin_7

#define DYMMY_BYTE      0x00

void GPIO_Configuration();

/* USART header */

#define GPIO_USART GPIOA

#define GPIO_USART_Rx_Pin GPIO_Pin_10

#define GPIO_USART_Tx_Pin GPIO_Pin_9

#define USARTy          USART1

#define USARTy_GPIO     GPIOA

#define USARTy_TxPin    GPIO_Pin_9

#define USARTy_RxPin    GPIO_Pin_10

#define USARTy_ClkPin   GPIO_Pin_8

void SerialPutChar (uint8_t c);

void Serial_PutString(uint8_t *s);

uint8_t USART_GetCharacter(USART_TypeDef* usart_p);

int fputc(int ch, FILE *f);

void USARTy_Init();

/* RCC header */

void RCC_Configuration();

/* SPI header */

void SPI_Configuration();

--------------------------------------------- RCC.c ---------------------------------------------

void RCC_Configuration()

{

  /* USART1, SPI1, USART1 SPI1 PORT clock enable */

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);

}

--------------------------------------------- GPIO.c ---------------------------------------------

void GPIO_Configuration()

{

  GPIO_InitTypeDef GPIO_InitStructure;

   

  /* Configure USARTy TX and USARTy CK pins as alterante function push-pull */

  GPIO_InitStructure.GPIO_Pin = GPIO_USART_Tx_Pin | USARTy_ClkPin;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

  GPIO_Init(USARTy_GPIO, &GPIO_InitStructure);

  

  /* Configure SPI1 pins : SCK, MISO and MOSI */

  GPIO_InitStructure.GPIO_Pin = SPIy_SCKPin | SPIy_MISOPin | SPIy_MOSIPin;

  GPIO_Init(SPIy_GPIO, &GPIO_InitStructure);

  

  /* Configure USARTy RX as input floating */

  GPIO_InitStructure.GPIO_Pin = USARTy_RxPin;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

  GPIO_Init(USARTy_GPIO, &GPIO_InitStructure);

}

위 코드는 stm사에서 제공하는 예제 코드를 사용하여 SPI USART 통신을 성공한 code이다. 그런데 이상한 것은 SPI slave 입장에서는 SPIy_SCKPin과 SPIy_MOSIPin이 input mode를 사용해야 하지 않을까?? 나중에 다시 코드를 바꾼 후 실험해봐야겠다.

--------------------------------------------- USART.c ---------------------------------------------

/* Private define ------------------------------------------------------------*/

#define TxBufferSize1   (countof(TxBuffer1) - 1)

#define TxBufferSize2   (countof(TxBuffer2) - 1)

/* Private variables ---------------------------------------------------------*/

uint8_t TxBuffer1[] = "USART Synchronous Example: USARTy -> SPIy using TXE and RXNE Flags";

uint8_t TxBuffer2[] = "USART Synchronous Example: SPIy -> USARTy using TXE and RXNE Flags";

uint8_t RxBuffer1[TxBufferSize2];

uint8_t RxBuffer2[TxBufferSize1];

__IO uint8_t NbrOfDataToRead1 = TxBufferSize2;

__IO uint8_t NbrOfDataToRead2 = TxBufferSize1;

__IO uint8_t TxCounter1 = 0, RxCounter1 = 0;

__IO uint8_t TxCounter2 = 0, RxCounter2 = 0;

USART_InitTypeDef USART_InitStructure;

USART_ClockInitTypeDef USART_ClockInitStructure; 

void USARTy_Init()

{

  /* USARTy configuration ------------------------------------------------------*/

  /* USARTy configured as follow:

        - BaudRate = 115200 baud  

        - Word Length = 8 Bits

        - One Stop Bit

        - No parity

        - Hardware flow control disabled (RTS and CTS signals)

        - Receive and transmit enabled

        - USART Clock Enabled

        - USART CPOL: Clock is active High

        - USART CPHA: Data is captured on the second edge 

        - USART LastBit: The clock pulse of the last data bit is output to 

                         the SCLK pin

  */

  USART_ClockInitStructure.USART_Clock = USART_Clock_Enable;

  USART_ClockInitStructure.USART_CPOL = USART_CPOL_High;

  USART_ClockInitStructure.USART_CPHA = USART_CPHA_2Edge;

  USART_ClockInitStructure.USART_LastBit = USART_LastBit_Enable;

  USART_ClockInit(USARTy, &USART_ClockInitStructure);

  USART_InitStructure.USART_BaudRate = 115200;

  USART_InitStructure.USART_WordLength = USART_WordLength_8b;

  USART_InitStructure.USART_StopBits = USART_StopBits_1;

  USART_InitStructure.USART_Parity = USART_Parity_No ;

  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;

  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

  USART_Init(USARTy, &USART_InitStructure);

  

  /* Configure the USARTy */

  USART_Init(USARTy, &USART_InitStructure);

  /* Enable the USARTy */

  USART_Cmd(USARTy, ENABLE);

}

--------------------------------------------- SPI.c ---------------------------------------------

void SPI_Configuration()

{

  SPI_InitTypeDef SPI_InitStructure;

  SPI_StructInit(&SPI_InitStructure);

  SPI_I2S_DeInit(SPIy);

  /* SPIy Config */

  SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;

  SPI_InitStructure.SPI_Mode = SPI_Mode_Slave;

  SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;

  SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;

  SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;

  SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;

  SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_LSB;

  

  /* Configure SPIy */

  SPI_Init(SPIy, &SPI_InitStructure);

  /* SPIy enable */

  SPI_Cmd(SPIy, ENABLE);

}

--------------------------------------------- main.c ---------------------------------------------

void main()

{

  RCC_Configuration();  

  GPIO_Configuration();

  SPI_Configuration();

  USARTy_Init();

    

  while(NbrOfDataToRead2--)

  {

    /* Write one byte in the USARTy Transmit Data Register */

    USART_SendData(USARTy, TxBuffer1[TxCounter1++]);

    /* Wait until end of transmit */

    

    //while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);

    

    while(USART_GetFlagStatus(USARTy, USART_FLAG_TC) == RESET)

    {

    }

    /* Wait the byte is entirely received by SPIy */  

    while(SPI_I2S_GetFlagStatus(SPIy, SPI_I2S_FLAG_RXNE) == RESET)

    {

    }

    /* Store the received byte in the RxBuffer2 */

    RxBuffer2[RxCounter2++] = SPI_I2S_ReceiveData(SPIy);

  }

  /* Clear the USARTy Data Register */

  USART_ReceiveData(USARTy);

  while(NbrOfDataToRead1--)

  {

    /* Wait until end of transmit */

    while(SPI_I2S_GetFlagStatus(SPIy, SPI_I2S_FLAG_TXE)== RESET)

    {

    }

    /* Write one byte in the SPIy Transmit Data Register */

    SPI_I2S_SendData(SPIy, TxBuffer2[TxCounter2++]);

    /* Send a Dummy byte to generate clock to slave */ 

    USART_SendData(USARTy, DYMMY_BYTE);

    /* Wait until end of transmit */

    while(USART_GetFlagStatus(USARTy, USART_FLAG_TC) == RESET)

    {

    }

    /* Wait the byte is entirely received by USARTy */

    while(USART_GetFlagStatus(USARTy, USART_FLAG_RXNE) == RESET)

    {

    }

    /* Store the received byte in the RxBuffer1 */

    RxBuffer1[RxCounter1++] = USART_ReceiveData(USARTy);

  }

  printf ("\r\nRxBuffer1 : %s \r\n", RxBuffer1);

  printf ("RxBuffer2 : %s \r\n", RxBuffer2);

  

  while(1)

  {

    

  }

}