SPI based on firmware library

SPI Structure

typedef struct
{
    
  uint16_t SPI_Direction;           // Direction  
  uint16_t SPI_Mode;                // Pattern 
  uint16_t SPI_DataSize;            // data size 
  uint16_t SPI_CPOL;                // Clock polarity 
  uint16_t SPI_CPHA;                // Clock phase 
  uint16_t SPI_NSS;                 //NSS position 
  uint16_t SPI_BaudRatePrescaler;   // Baud rate 
  uint16_t SPI_FirstBit;            // Select whether the data transmission direction starts high or low  
  uint16_t SPI_CRCPolynomial;       //CRC Check bit 
}SPI_InitTypeDef;

SPI The configuration process

① Configure pins , Can make the clock 
void GPIO_Init(GPIO_TypeDef* GPIOx, GPIO_InitTypeDef* GPIO_InitStruct);
② initialization SPI, Set the working mode 
void SPI_Init(SPI_TypeDef* SPIx, SPI_InitTypeDef* SPI_InitStruct);

③ Can make SPIx
void SPI_Cmd(SPI_TypeDef* SPIx, FunctionalState NewState);


④SPI To transmit data 
void SPI_I2S_SendData(SPI_TypeDef* SPIx, uint16_t Data); uint16_t SPI_I2S_ReceiveData(SPI_TypeDef* SPIx);


⑤ see SPI Transmission status 
FlagStatus SPI_I2S_GetFlagStatus(SPI_TypeDef* SPIx, uint16_t SPI_I2S_FLAG);

initialization SPI

void SPI2_Init(void)//SPI2 initialization   Main mode 
{
    
	SPI_InitTypeDef  SPI_InitStructure;
	GPIO_InitTypeDef GPIO_InitStructure;
	
	/* Enable SPI1 and GPIOA clocks */
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);
	
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2,ENABLE);

	/* Configure SPI1 pins: NSS, SCK, MISO and MOSI */
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;//SCK MOSI 
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;//PB13/14/15 Multiplexing push pull output  
	GPIO_Init(GPIOB, &GPIO_InitStructure);
  	GPIO_SetBits(GPIOB,GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15);//PB13/14/15 Pull up 
	
	/* SPI2 configuration */ 
	SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex; //SPI2 Set to two-wire full duplex 
	SPI_InitStructure.SPI_Mode = SPI_Mode_Master;	                   // Set up SPI2 Main mode 
	SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;                  //SPI Send receive 8 Bit frame structure 
	SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;	 		               // The serial clock does not operate in the state （ Free ） when , The clock is high 
	SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;		               // The second clock edge starts sampling data （ Here is the rising edge acquisition data ）
	SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;			               //NSS The signal is controlled by software （ Use SSI position ） management 
	SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_8; // Define the baud rate prescaler value : Baud rate prescaler value is 8, After frequency division, it is 9MHZ
	SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;				   // Data transfer from MSB Bit start high 
	SPI_InitStructure.SPI_CRCPolynomial = 7;						   //CRC The polynomial of the value calculation 
	SPI_Init(SPI2, &SPI_InitStructure);
	
	/* Enable SPI2 */
	SPI_Cmd(SPI2, ENABLE); 											  // Can make SPI1 peripherals 
}

Read and write bytes

u8 SPI2_ReadWriteByte(u8 Data)
{
    
	unsigned char t = 0;
	
	while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET) /*  Constantly check whether the flag is 0 Send empty  */
	{
    
		t++;
		
		if(t>=200)  /*  Overtime  */
		{
    
			return 0;
		}
	}
	
	SPI_I2S_SendData(SPI2, Data); /*  send data  */

	while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == RESET) /*  be equal to 0 That is, the reception is empty  */
	{
    
		t++;
		
		if(t>=200)
		{
    
			return 0;
		}
	}
	
	return  SPI_I2S_ReceiveData(SPI2);   /*  Return the received data  */

}

Set up SPI Baud rate
stay STM32 Firmware library and provided routines , You can see it everywhere assert_param() Use . If you open any of the routines stm32f10x_conf.h file , You can see that actually assert_param Is a macro definition ;
In the firmware library , Its function is to detect whether the parameter passed to the function is a valid parameter .
Illustrate with examples ：
　　assert_param(IS_USART_ALL_PERIPH(USARTx));　　
　 This code is used to check parameters USARTx Whether it works , among IS_USART_ALL_PERIPH(USARTx) Is a macro definition , as follows ：

#define IS_USART_ALL_PERIPH(PERIPH) (((PERIPH) == USART1) || \ ((PERIPH) == USART2) || \ ((PERIPH) == USART3) || \ ((PERIPH) == USART4) || \ ((PERIPH) == USART5) || \ ((PERIPH) == USART6) || \ ((PERIPH) == USART7) || \ ((PERIPH) == USART8))

The function of macro definition is parameter USARTx yes USART1~USART8 One of them , Said parameters USARTx It works , return true, Otherwise return to false.

void SPI2_SetSpeed(u8 SPI_BaudRatePrescaler)
{
    
	assert_param(IS_SPI_BAUDRATE_PRESCALER(SPI_BaudRatePrescaler)); /*  The parameter is frequency division  */
	
	SPI2->CR1 &= 0XFFC7; //&1111 1111 1100 0111 /*  hold D3~D4 Zero clearing 
	SPI2->CR1 |= SPI_BaudRatePrescaler; /*  Here is the handle. SPI_BaudRatePrescaler The value of is equal to SPI2->CR1 Press the value in 2 Add in hexadecimal  */
	/*  If SPI_BaudRatePrescaler The value of is 0x038, Binary numbers are 00111000 And 1111 1111 1100 0111 The result is 1111 1111 1111 1111->0XFFFF;*/ 
	
	SPI_Cmd(SPI2, ENABLE);

}