void SPI_RCC_config(void)

{

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1,ENABLE);

}

void SPI_GPIO_config(void)

{

GPIO_InitTypeDef GPIO_InitStructure;;

GPIO_InitStructure.GPIO_Pin=GPIO_Pin_5;//SCK

GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;

GPIO_Init(GPIOA,&GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin=GPIO_Pin_7;//MOSI

GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;

GPIO_Init(GPIOA,&GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin=GPIO_Pin_6;//MISO

GPIO_InitStructure.GPIO_Mode=GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOA,&GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin=GPIO_Pin_8;//cs

GPIO_InitStructure.GPIO_Mode=GPIO_Mode_Out_PP;

GPIO_Init(GPIOA,&GPIO_InitStructure);

}

void SPI_configuration(void)

{

SPI_InitTypeDef SPI_InitStructure;

SPI_InitStructure.SPI_Direction=SPI_Direction_2Lines_FullDuplex;//設(shè)置SPI單向或者雙向的數(shù)據(jù)模式:SPI設(shè)置為雙線雙向全雙工

SPI_InitStructure.SPI_Mode=SPI_Mode_Master;//設(shè)置SPI工作模式:設(shè)置為主SPI

SPI_InitStructure.SPI_DataSize=SPI_DataSize_8b;//設(shè)置SPI的數(shù)據(jù)大小:SPI發(fā)送接收8位幀結(jié)構(gòu)

SPI_InitStructure.SPI_CPOL=SPI_CPOL_High;//選擇了串行時鐘的穩(wěn)態(tài):時鐘懸空高

SPI_InitStructure.SPI_CPHA=SPI_CPHA_2Edge;//數(shù)據(jù)捕獲于第二個時鐘沿

SPI_InitStructure.SPI_NSS=SPI_NSS_Soft;//NSS信號由硬件（NSS管腳）還是軟件（使用SSI位）管理:內(nèi)部NSS信號有SSI位控制

SPI_InitStructure.SPI_BaudRatePrescaler=SPI_BaudRatePrescaler_256;//定義波特率預(yù)分頻的值:波特率預(yù)分頻值為256

SPI_InitStructure.SPI_FirstBit=SPI_FirstBit_MSB;//指定數(shù)據(jù)傳輸從MSB位還是LSB位開始:數(shù)據(jù)傳輸從MSB位開始

SPI_InitStructure.SPI_CRCPolynomial=7;//CRC值計算的多項式

SPI_Init(SPI1,&SPI_InitStructure);

SPI_Cmd(SPI1, ENABLE);//使能SPI外設(shè)

}

//SPIx 讀寫一個字節(jié)

//TxData:要寫入的字節(jié)

//返回值:讀取到的字節(jié)

u8 SPI_SendByte(u8 byte)

{

while(SPI_I2S_GetFlagStatus(SPI1,SPI_I2S_FLAG_TXE)==RESET);

SPI_I2S_SendData( SPI1,byte);

while(SPI_I2S_GetFlagStatus(SPI1,SPI_I2S_FLAG_RXNE)==RESET);

return SPI_I2S_ReceiveData(SPI1);

}

//SPI 速度設(shè)置函數(shù)

//SpeedSet:

//SPI_BaudRatePrescaler_2 2分頻 (SPI 36M@sys 72M)

//SPI_BaudRatePrescaler_8 8分頻 (SPI 9M@sys 72M)

//SPI_BaudRatePrescaler_16 16分頻 (SPI 4.5M@sys 72M)

//SPI_BaudRatePrescaler_256 256分頻 (SPI 281.25K@sys 72M)

void SPIx_Speedhigh(void)

{

SPI_InitTypeDef SPI_InitStructure;

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_2;

SPI_InitStructure.SPI_FirstBit=SPI_FirstBit_MSB;

SPI_InitStructure.SPI_CRCPolynomial=7;

SPI_Init(SPI1,&SPI_InitStructure);

SPI_Cmd(SPI1, ENABLE);

}

void SPIx_Speedlow(void)

{

SPI_InitTypeDef SPI_InitStructure;

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);

SPI_Cmd(SPI1, ENABLE);

}

重難點：關(guān)于SPI_NSS可以選用三中配置

1：硬件主、從模式：浮空輸入或帶上拉輸入或帶下拉輸入

2：硬件主模式/NSS輸出管理

3：軟件模式 可作普通IO口

我們一般選用軟件模式，用一個IO做CS端