代码收藏家技术教程 2024-09-27

STM32之间SPI通信数据传输详解

利用STM32F103C6T6最小系统板实现SPI的通信，其中肯定会有一主一从。这里我利用面包板进行连接，从机32会有OLED屏幕显示接收内容，来验证数据的对错。实物图如下：

其中杜邦线接线部分为：主机PA4接从机PA4、主机PA5接从机PA5、主机PA6接从机PA6以及主机PA7接从机PA7。这里MISO接MISO以及MOSI接MOSI是因为我们配置库函数中将主机32配置为主机，则他就是MISO中的MI，从机32配置为从机，那么它就是MISO中的SO，所以如此接线。

现在展示从机库函数配置部分（头文件含有Master是因为刚开时命名错了）：

#include "STM32_SPI_Master.h"

void STM32_SPI_Master_Init(void)
{
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
	
	GPIO_InitTypeDef GPIO_InitStructure;
	
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	
	GPIO_Init(GPIOA, &GPIO_InitStructure);
	
	SPI_InitTypeDef SPI_InitStructure;
	SPI_StructInit(&SPI_InitStructure);
	SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_128;
	SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
	SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
	SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
	SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_RxOnly;
	SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
	SPI_InitStructure.SPI_Mode = SPI_Mode_Slave;
	SPI_InitStructure.SPI_CRCPolynomial = 7;
	SPI_Init(SPI1, &SPI_InitStructure);
	
	SPI_Cmd(SPI1, ENABLE);
	
	SPI_I2S_ClearITPendingBit(SPI1, SPI_I2S_IT_RXNE);
	SPI_I2S_ITConfig(SPI1, SPI_I2S_IT_RXNE, ENABLE);
	
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
	
	NVIC_InitTypeDef NVIC_InitStructure;
	NVIC_InitStructure.NVIC_IRQChannel = SPI1_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
	NVIC_Init(&NVIC_InitStructure);
}

我们配置从机为SPI通信模式0，双线只接受模式，高位在前，8位数据帧。采用中断的方式接收数据。

其中IO口模式配置十分重要，MOSI、CLK和NSS要配置为上拉或者浮空输入。MISO要配置为复用推挽输出。

接下来是主机的SPI标准库函数配置：

#include "STM32_SPI_Slave.h"

void STM32_SPI_W_CS(BitAction BitValue)
{
	GPIO_WriteBit(GPIOA, GPIO_Pin_4, BitValue);
}

void STM32_SPI_Slave_Init(void)
{
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
	
	GPIO_InitTypeDef GPIO_InitStructure;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOA, &GPIO_InitStructure);
	
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOA, &GPIO_InitStructure);
	
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOA, &GPIO_InitStructure);		
	
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOA, &GPIO_InitStructure);		

	SPI_InitTypeDef SPI_InitStructure;
	SPI_StructInit(&SPI_InitStructure);
	SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_128;
	SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
	SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
	SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
	SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
	SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
	SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
	SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
	SPI_InitStructure.SPI_CRCPolynomial = 7;
	SPI_Init(SPI1, &SPI_InitStructure);
	
	SPI_Cmd(SPI1, ENABLE);
}

void STM32_SPI_Start(void)
{
	STM32_SPI_W_CS(0);
}

void STM32_SPI_Stop(void)
{
	STM32_SPI_W_CS(1);
}

void STM32_SPI_SendData(uint8_t Data)
{
	while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) != SET);
	SPI_I2S_SendData(SPI1, Data);
	while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) != SET);
	SPI_I2S_ReceiveData(SPI1);
}

void STM32_SPI_Send(uint8_t Data)
{
	STM32_SPI_Start();
	STM32_SPI_SendData(Data);
	STM32_SPI_Stop();
}

SPI结构通赋值中的SPI模式、波特率分频、CRC多项式检验、数据帧和什么位在前从机和主机赋值要相同。

GPIO口模式配置其中MOSI、CLK要为复用推挽输出、MISO要为上拉或浮空输入、NSS要为推挽输出。NSS一定要是推挽输出，不能为复用推挽输出（复用推挽输出对于推挽输出的区别为除了能当普通IO口，还可以给SPI等外设使用）。我们这里NSS利用软件模拟即可。

主函数部分就是给从机发送数据1。

编写完程序后分别将程序下载进对应的单片机里，观察现象：