STM32如何配置使用SPI通信

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SPI是一种高速的，全双工，同步的通信总线，原理和使用简单，占用引脚资源少，是一种常用的通信方式。

STM32通常有2~3个SPI接口

根据STM32手册的使用方法：

1. Enable peripheral clock

2. Enable SCK, MOSI, MISO and NSS GPIOclocks

3. Peripherals alternate function:

 Connect the pin to the desired peripherals' AlternateFunction (AF)

 Call GPIO_Init() function.

4. Program the Polarity, Phase, First Data, Baud RatePrescaler, Slave Management,Peripheral Mode and CRC Polynomialvalues using the SPI_Init() function in SPI mode.

5. Configure the FIFO threshold usingSPI_RxFIFOThresholdConfig() to select at which hreshold the RXNEevent is generated.

6. Enable the NVIC and the corresponding interrupt using thefunction SPI_I2S_ITConfig() if you need to use interruptmode.

7. When using the DMA mode

 Configure the DMA using DMA_Init() function.

 Active the needed channel Request using SPI_I2S_DMACmd()function.

8. Enable the SPI using the SPI_Cmd() function .

9. Enable the DMA using the DMA_Cmd() function when using DMAmode.

10. To use the CRC Hardware calculation feature refer to thePeripheral CRC hardware Calculation subsection.

基于STM32F3discovery开发板，STM32F303VC

使用SPI1,从机连接的是L3GD20陀螺仪，引脚连接：

SPI1_MOSI——PA7

SPI1_SCK——PA5

SPI1_MISO——PA6

NSS——PE3

代码：

void SPI_GPIO_Config(void)

{

//将SPI1_MOSI—PA7,SPI1_SCK—PA5,SPI1_MISO—PA6引脚配置为对应复用功能

//NSS—PE3为从机片选引脚，配置为推挽输出

}

void SPI_Config(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_Low; //结合从机选择

SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge; //结合从机选择

SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;

SPI_InitStructure.SPI_BaudRatePrescaler =SPI_BaudRatePrescaler_8;

SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;

SPI_InitStructure.SPI_CRCPolynomial = 7;

SPI_I2S_DeInit(SPI1);

SPI_Init(SPI1,&SPI_InitStructure);

SPI_RxFIFOThresholdConfig(SPI1, SPI_RxFIFOThreshold_QF);

SPI_Cmd(SPI1,ENABLE);

}

然后就可以用SPI接口进行收发数据，具体收发方式要根据从机设备决定

需要的时候可以配置中断，DMA等功能

发送或接收数据前，先将相应从机的片选信号置零

SPI是两个设备移位寄存器的数据交换，接收数据前先向从机发送虚拟字节，收到的数据就是所要读取的数据

风子

2015,05,20

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