一、开启时钟,开启SPI和GPIO的时钟
二、初始化GPIO口,其中SCK和MOSI是由硬件外设控制的输出信号,配置为复用推挽输出
MISO是硬件外设的输入信号,配置为上拉输入,SS是软件控制的输出信号,配置为通用推挽输出
三、配置SPI外设,使用结构体调用SPI_Init
四、开关控制,调用SPI_Cmd,使能
void SPI_I2S_SendData(SPI_TypeDef* SPIx, uint16_t Data);//写DR数据寄存器
uint16_t SPI_I2S_ReceiveData(SPI_TypeDef* SPIx);//读DR
步骤
一、等待TXE为1,发送寄存器为空
二、软件写入数据置SPI_DR
三、等待RENE为1
四、读取DR
MySPI.c
#include "stm32f10x.h" // Device header
void MySPI_W_SS(uint8_t BitValue) //ss = cs
{
GPIO_WriteBit(GPIOA , GPIO_Pin_4, (BitAction)BitValue);
}
void MySPI_Init(void)
{
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
GPIO_InitTypeDef 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);
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | 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);
SPI_InitTypeDef SPI_InitStructure;
SPI_InitStructure.SPI_Mode = SPI_Mode_Master; //指定为主机
SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex; //双线全双工
SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b; //8位数据帧
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB; //高位先行
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_128;
SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge; //第一个边沿开始采样CPHA=0
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
SPI_InitStructure.SPI_CRCPolynomial = 7;
SPI_Init(SPI1, &SPI_InitStructure);
SPI_Cmd(SPI1 , ENABLE);
MySPI_W_SS(1);
}
void MySPI_Start(void)
{
MySPI_W_SS(0);
}
void MySPI_Stop(void)
{
MySPI_W_SS(1);
}
uint8_t MySPI_SwapByte(uint8_t ByteSend) //交换字节
{
while (SPI_I2S_GetFlagStatus(SPI1 , SPI_I2S_FLAG_TXE) != SET);
SPI_I2S_SendData(SPI1 , ByteSend);
while (SPI_I2S_GetFlagStatus(SPI1 , SPI_I2S_FLAG_RXNE) != SET);
return SPI_I2S_ReceiveData(SPI1);
}