STM32的SPI主从通信程序实列 -

#include "sys.h" //系统子函数
#include "usart.h"//串口子函数
#include "delay.h" //延时子函数
//PA4 SPI1_NSS
//PA5 SPI1_SCK
//PA6 SPI1_MISO
//PA7 SPI1_MOSI
// SPI总线速度设置
#define SPI_SPEED_2 0
#define SPI_SPEED_8 1
#define SPI_SPEED_16 2
#define SPI_SPEED_256 3
u8 Master_Temp =0;
void SPI1_Init(void); //初始化SPI口
void SPI1_SetSpeed(u8 SpeedSet); //设置SPI速度
u8 SPI1_ReadWriteByte(u8 TxData);//SPI总线读写一个字节
int main(void)
{
SystemInit();
delay_init(72); //延时初始化
NVIC_Configuration();
uart_init(9600);//串口初始化为9600
SPI1_Init(); //SPI1初始化
SPI1_SetSpeed(SPI_SPEED_256);
while(1)
{
// SPI1_ReadWriteByte(0x55);
SPI1_ReadWriteByte(0x78);
printf("Master_Temp =%x\r\n",Master_Temp);
delay_ms(100);
}
}
//SPI口初始化
//这里针是对SPI1的初始化
void SPI1_Init(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
RCC->APB2ENR|=1<<0; //复用
RCC->APB2ENR|=1<<2; //PORTA时钟使能
RCC->APB2ENR|=1<<12; //SPI1时钟使能
//这里只针对SPI口初始化
GPIOA->CRL&=0X000FFFFF;
GPIOA->CRL|=0XBBB00000;//PA5.6.7复用
GPIOA->ODR|=0X7<<5; //PA5.6.7上拉
SPI1->CR1|=0<<10;//全双工模式
SPI1->CR1|=1<<9; //软件nss管理
SPI1->CR1|=1<<8;
SPI1->CR1|=1<<2; //SPI主机
SPI1->CR1|=0<<11;//8bit数据格式
SPI1->CR1|=1<<1; //空闲模式下SCK为1 CPOL=1
SPI1->CR1|=1<<0; //数据采样从第二个时间边沿开始,CPHA=1
SPI1->CR1|=0<<3; //Fsck=Fcpu/256
SPI1->CR1|=0<<7; //MSBfirst
SPI1->CR2|=1<<6; //接收缓冲区非空中断使能
NVIC_InitStructure.NVIC_IRQChannel = SPI1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
SPI_I2S_ITConfig(SPI1,SPI_I2S_IT_RXNE,ENABLE);
SPI_Cmd(SPI1, ENABLE); //使能SPI外设
SPI1_ReadWriteByte(0xff);//启动传输
}
//SPI 速度设置函数
//SpeedSet:
//SPI_SPEED_2 2分频 (SPI 12M --sys 24M)
//SPI_SPEED_8 8分频 (SPI 3M --sys 24M)
//SPI_SPEED_16 16分频 (SPI 1.5M --sys 24M)
//SPI_SPEED_256 256分频 (SPI 905.6K --sys 24M)
void SPI1_SetSpeed(u8 SpeedSet)
{
SPI1->CR1&=0XFFC7;//Fsck=Fcpu/256
if(SpeedSet==SPI_SPEED_2)//二分频
{
SPI1->CR1|=0<<3;//Fsck=Fpclk/2=36Mhz
}else if(SpeedSet==SPI_SPEED_8)//八分频
{
SPI1->CR1|=2<<3;//Fsck=Fpclk/8=9Mhz
}else if(SpeedSet==SPI_SPEED_16)//十六分频
{
SPI1->CR1|=3<<3;//Fsck=Fpclk/16=4.5Mhz
}else //256分频
{
SPI1->CR1|=7<<3; //Fsck=Fpclk/256=281.25Khz 低速模式
}
SPI1->CR1|=1<<6; //SPI设备使能
}
//SPIx 读写一个字节
//TxData:要写入的字节
//返回值:读取到的字节
u8 SPI1_ReadWriteByte(u8 TxData)
{
u8 retry=0;
while((SPI1->SR&1<<1)==0)//等待发送区空
{
retry++;
if(retry>200)return 0;
}
SPI1->DR=TxData; //发送一个byte
retry=0;
while((SPI1->SR&1<<0)==0) //等待接收完一个byte
{
retry++;
if(retry>200)return 0;
}
return SPI1->DR; //返回收到的数据
}
u8 SPI1_ReadByte(u8 TxData)
{
u8 retry=0;
while((SPI1->SR&1<<0)==0) //等待接收完一个byte
{
retry++;
if(retry>200)return 0;
}
return SPI1->DR; //返回收到的数据
}
void SPI1_IRQHandler(void)
{
if((SPI1->SR&1<<0)==1)
{
Master_Temp =
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