spi.c

LWIP在STM32裸机上的移植

//F_CS      : PA4
//SPI1_CLK  : PA5
//SPI1_MISO : PA6
//SPI1_MOSI : PA7

#include "spi.h"
#include <stdio.h>

/*******************************************************************************
* Function Name  : SPI_FLASH_Init
* Description    : Initializes the peripherals used by the SPI FLASH driver.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void SPI_Configuration(void)
{
  	SPI_InitTypeDef  SPI_InitStructure;
  
  	RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
  
	GPIOA->CRL &= 0X0000FFFF; 
	GPIOA->CRL |= 0XBBB30000;	//GPIO_Mode_AF_PP	    	
//	GPIOA->ODR |= 7<<5; 
	GPIOA->ODR |= 1<<4;			//F_CS -> PA4

  	/* Deselect the FLASH: Chip Select high */
//	SPI_FLASH_CS_HIGH();

  	/* SPI1 configuration */
  	SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
  	SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
  	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_BaudRatePrescaler = SPI_BaudRatePrescaler_256;
  	SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
  	SPI_InitStructure.SPI_CRCPolynomial = 7;
  	SPI_Init(SPI1, &SPI_InitStructure);

  	/* Enable SPI1  */
  	SPI_Cmd(SPI1, ENABLE);
}

/*******************************************************************************
* Function Name  : SPI_SendByte
* Description    : Sends a byte through the SPI interface and return the byte
*                  received from the SPI bus.
* Input          : byte : byte to send.
* Output         : None
* Return         : The value of the received byte.
*******************************************************************************/
u8 SPI_SendByte(u8 byte)
{
  /* Loop while DR register in not emplty */
  while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);

  /* Send byte through the SPI1 peripheral */
  SPI_I2S_SendData(SPI1, byte);

  /* Wait to receive a byte */
  while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);

  /* Return the byte read from the SPI bus */
  return SPI_I2S_ReceiveData(SPI1);
}