1.uart
（1）一些最基本的原理以及通信方式
首先其工作原理是将数据以串行方式进行发的，接收的时候将数据转换为并行数据。利用异步通信所以不需要时钟线适用于不同芯片、芯片对模块之间的控制。因此需要设置好波特率（115200、9500）数据位、停止位、奇偶效验位。
（2）实际应用中的一些具体操作
在实际应用中不管你是要发数据还是要收数据，首先得拿出一个空余的存储空间出来（buff）对uart进行初始化，首先对其映射的引脚进行初始化，设置波特率，中断的优先级，收或者发、数据位、停止位、奇偶效验位。最后利用定时器或者其他方式一直往buff里面写入数据，并且判断buff是否被填满，填满即可发送给所需要接受的设备即可。
收数据也需初始化上述的一系列操作，就依据发数据时所设定的波特率、数据位、停止位、奇偶效验位，等进行解包读取真实数据。
在我们一般的使用过程之中通常将其封装为8位，第一位和最后一位作为数据包的判断位，第一位如果正确将这个数据包进行解读，解读到最后一位如果也正确就对这个数据获取进行下一步的运用。如果第一位和最后一位有错误则对数据进行丢弃。
（3）具体代码如下
uart.c
#include "sys.h"
#include "usart.h"
#include "led.h"
#include "delay.h"
//
//Èç¹ûʹÓÃucos,Ôò°üÀ¨ÏÂÃæµÄÍ·Îļþ¼´¿É.
RingBuff_t Uart2_RingBuff,Uart1_RingBuff,Uart3_RingBuff;//´´½¨Ò»¸öringBuffµÄ»º³åÇø
uint16_t distance = 0;
//¼ÓÈëÒÔÏ´úÂë,Ö§³Öprintfº¯Êý,¶ø²»ÐèҪѡÔñuse MicroLIB
#if 1
#pragma import(__use_no_semihosting)
//±ê×¼¿âÐèÒªµÄÖ§³Öº¯Êý
struct __FILE
{ int handle;
}; FILE __stdout;
//¶¨Òå_sys_exit()ÒÔ±ÜÃâʹÓðëÖ÷»úģʽ
void _sys_exit(int x)
{ x = x;
}
//Öض¨Òåfputcº¯Êý
int fputc(int ch, FILE *f)
{ while((USART1->SR&0X40)==0);//Ñ»··¢ËÍ,Ö±µ½·¢ËÍÍê±Ï USART1->DR = (u8) ch; return ch;
}
#endif//³õʼ»¯IO ´®¿Ú1
//bound:²¨ÌØÂÊ
void uart_init(u32 bound){//GPIO¶Ë¿ÚÉèÖÃGPIO_InitTypeDef GPIO_InitStructure;USART_InitTypeDef USART_InitStructure;NVIC_InitTypeDef NVIC_InitStructure;RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE); //ʹÄÜGPIOAʱÖÓRCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);//ʹÄÜUSART1ʱÖÓ//´®¿Ú1¶ÔÓ¦Òý½Å¸´ÓÃÓ³ÉäGPIO_PinAFConfig(GPIOA,GPIO_PinSource9,GPIO_AF_USART1); //GPIOA9¸´ÓÃΪUSART1GPIO_PinAFConfig(GPIOA,GPIO_PinSource10,GPIO_AF_USART1); //GPIOA10¸´ÓÃΪUSART1//USART1¶Ë¿ÚÅäÖÃGPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10; //GPIOA9ÓëGPIOA10GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//¸´Óù¦ÄÜGPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //ËÙ¶È50MHzGPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //ÍÆÍ츴ÓÃÊä³öGPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //ÉÏÀGPIO_Init(GPIOA,&GPIO_InitStructure); //³õʼ»¯PA9£¬PA10//USART1 ³õʼ»¯ÉèÖÃUSART_InitStructure.USART_BaudRate = bound;//²¨ÌØÂÊÉèÖÃUSART_InitStructure.USART_WordLength = USART_WordLength_8b;//×Ö³¤Îª8λÊý¾Ý¸ñʽUSART_InitStructure.USART_StopBits = USART_StopBits_1;//Ò»¸öֹͣλUSART_InitStructure.USART_Parity = USART_Parity_No;//ÎÞÆæżУÑéλUSART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//ÎÞÓ²¼þÊý¾ÝÁ÷¿ØÖÆUSART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //ÊÕ·¢Ä£Ê½USART_Init(USART1, &USART_InitStructure); //³õʼ»¯´®¿Ú1USART_Cmd(USART1, ENABLE); //ʹÄÜ´®¿Ú1 USART_ClearFlag(USART1, USART_FLAG_TC);#if EN_USART1_RX USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);//¿ªÆôÏà¹ØÖжÏ//Usart1 NVIC ÅäÖÃNVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;//´®¿Ú1ÖжÏͨµÀNVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;//ÇÀÕ¼ÓÅÏȼ¶3NVIC_InitStructure.NVIC_IRQChannelSubPriority =1; //×ÓÓÅÏȼ¶3NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQͨµÀʹÄÜNVIC_Init(&NVIC_InitStructure); //¸ù¾ÝÖ¸¶¨µÄ²ÎÊý³õʼ»¯NVIC¼Ä´æÆ÷#endif
}void USART1_IRQHandler(void) //´®¿Ú1ÖжϷþÎñ³ÌÐò
{uint8_t rdata;if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET) { rdata = USART_ReceiveData(USART1);if(Write_RingBuff(&Uart1_RingBuff, rdata) == RINGBUFF_ERR){//»º³åÇøÂúµÆÁÁLED1=0;}else{LED1=1;}}
} void uart2_v831_init(uint32_t bound){//GPIO¶Ë¿ÚÉèÖÃGPIO_InitTypeDef GPIO_InitStructure;USART_InitTypeDef USART_InitStructure;NVIC_InitTypeDef NVIC_InitStructure;RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD,ENABLE); RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2,ENABLE);//´®¿Ú2¶ÔÓ¦Òý½Å¸´ÓÃÓ³ÉäGPIO_PinAFConfig(GPIOD,GPIO_PinSource6,GPIO_AF_USART2); GPIO_PinAFConfig(GPIOD,GPIO_PinSource5,GPIO_AF_USART2); //USART1¶Ë¿ÚÅäÖÃGPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_5; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//¸´Óù¦ÄÜGPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //ËÙ¶È50MHzGPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //ÍÆÍ츴ÓÃÊä³öGPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //ÉÏÀGPIO_Init(GPIOD,&GPIO_InitStructure);//USART2 ³õʼ»¯ÉèÖÃUSART_InitStructure.USART_BaudRate = bound;//²¨ÌØÂÊÉèÖÃUSART_InitStructure.USART_WordLength = USART_WordLength_8b;//×Ö³¤Îª8λÊý¾Ý¸ñʽUSART_InitStructure.USART_StopBits = USART_StopBits_1;//Ò»¸öֹͣλUSART_InitStructure.USART_Parity = USART_Parity_No;//ÎÞÆæżУÑéλUSART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//ÎÞÓ²¼þÊý¾ÝÁ÷¿ØÖÆUSART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //ÊÕ·¢Ä£Ê½USART_Init(USART2, &USART_InitStructure); //³õʼ»¯´®¿ÚUSART_Cmd(USART2, ENABLE); //ʹÄÜ´®¿Ú2 USART_ClearFlag(USART2, USART_FLAG_TC);USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);//¿ªÆôÏà¹ØÖжÏ//Usart2 NVIC ÅäÖÃNVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;//´®¿Ú2ÖжÏͨµÀNVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;//ÇÀÕ¼ÓÅÏȼ¶NVIC_InitStructure.NVIC_IRQChannelSubPriority =0; //×ÓÓÅÏȼ¶NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQͨµÀʹÄÜNVIC_Init(&NVIC_InitStructure); //¸ù¾ÝÖ¸¶¨µÄ²ÎÊý³õʼ»¯NVIC¼Ä´æÆ÷
}void USART2_IRQHandler(void) //´®¿Ú2ÖжϷþÎñ³ÌÐò
{uint8_t rdata;if(USART_GetITStatus(USART2, USART_IT_RXNE) != RESET){ rdata = USART_ReceiveData(USART2);if(Write_RingBuff(&Uart2_RingBuff, rdata) == RINGBUFF_ERR){//»º³åÇøÂúµÆÁÁLED1=0;}else{LED1=1;}}
} void uart3_init(uint32_t bound){//GPIO¶Ë¿ÚÉèÖÃGPIO_InitTypeDef GPIO_InitStructure;USART_InitTypeDef USART_InitStructure;NVIC_InitTypeDef NVIC_InitStructure;RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB,ENABLE); RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3,ENABLE);GPIO_PinAFConfig(GPIOB,GPIO_PinSource10,GPIO_AF_USART3); GPIO_PinAFConfig(GPIOB,GPIO_PinSource11,GPIO_AF_USART3); //USART1¶Ë¿ÚÅäÖÃGPIO_InitStructure.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//¸´Óù¦ÄÜGPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //ËÙ¶È50MHzGPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //ÍÆÍ츴ÓÃÊä³öGPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //ÉÏÀGPIO_Init(GPIOB,&GPIO_InitStructure);//USART3 ³õʼ»¯ÉèÖÃUSART_InitStructure.USART_BaudRate = bound;//²¨ÌØÂÊÉèÖÃUSART_InitStructure.USART_WordLength = USART_WordLength_8b;//×Ö³¤Îª8λÊý¾Ý¸ñʽUSART_InitStructure.USART_StopBits = USART_StopBits_1;//Ò»¸öֹͣλUSART_InitStructure.USART_Parity = USART_Parity_No;//ÎÞÆæżУÑéλUSART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//ÎÞÓ²¼þÊý¾ÝÁ÷¿ØÖÆUSART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //ÊÕ·¢Ä£Ê½USART_Init(USART3, &USART_InitStructure); //³õʼ»¯´®¿ÚUSART_Cmd(USART3, ENABLE); //ʹÄÜ´®¿Ú2 USART_ClearFlag(USART3, USART_FLAG_TC);USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);//¿ªÆôÏà¹ØÖжÏ//USART3 NVIC ÅäÖÃNVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;//´®¿Ú2ÖжÏͨµÀNVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=1;//ÇÀÕ¼ÓÅÏȼ¶NVIC_InitStructure.NVIC_IRQChannelSubPriority =0; //×ÓÓÅÏȼ¶NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQͨµÀʹÄÜNVIC_Init(&NVIC_InitStructure); //¸ù¾ÝÖ¸¶¨µÄ²ÎÊý³õʼ»¯NVIC¼Ä´æÆ÷
}void USART3_IRQHandler(void)
{uint8_t rdata;if(USART_GetITStatus(USART3, USART_IT_RXNE) != RESET){ rdata = USART_ReceiveData(USART3);if(Write_RingBuff(&Uart3_RingBuff, rdata) == RINGBUFF_ERR){//»º³åÇøÂúµÆÁÁLED1=0;}else{LED1=1;}}
} uint16_t get_distance(void)
{uint16_t mm = 0;uint8_t cmd = 0x55;static uint16_t i;i++;if(Uart3_RingBuff.Lenght == 2){i=0;uint8_t data = 0;Read_RingBuff(&Uart3_RingBuff, &data);mm = data;Read_RingBuff(&Uart3_RingBuff, &data);mm = mm << 8 | data;//delay_us(1000);usart_send(USART3,&cmd,1);} if(i==100 || Uart3_RingBuff.Lenght > 2){ //Ò»ÃëRingBuff_Init(&Uart3_RingBuff);usart_send(USART3,&cmd,1);}return mm;
}uint8_t DataDecode(RingBuff_t *ringbuff, uint8_t *data1, uint8_t *data2)
{static uint8_t uart_dec_count;static uint8_t uart_rec_data[5];uint8_t ret = 1;if(Read_RingBuff(ringbuff, &uart_rec_data[uart_dec_count]) == RINGBUFF_ERR){return 1;}if((uart_dec_count == 0)&&(uart_rec_data[uart_dec_count] != 0x55)) { //¼ì²âµÚÒ»¸öÊý¾ÝÊÇ·ñΪ0x55uart_rec_data[uart_dec_count] = 0; } else if((uart_dec_count == 1)&&(uart_rec_data[uart_dec_count] != 0xaa)){ //¼ì²âµÚ¶þ¸öÊý¾ÝÊÇ·ñΪ0xaauart_rec_data[uart_dec_count] = 0;uart_rec_data[uart_dec_count-1] = 0;uart_dec_count = 0;} else if((uart_dec_count == 4)&&(uart_rec_data[uart_dec_count] != 0xfa)){uart_rec_data[uart_dec_count] = 0;uart_rec_data[uart_dec_count-1] = 0;uart_rec_data[uart_dec_count-2] = 0;uart_rec_data[uart_dec_count-3] = 0;uart_rec_data[uart_dec_count-4] = 0;uart_dec_count = 0;} else {if(uart_dec_count == 4)//³É¹¦½ÓÊÕÒ»Ö¡Êý¾Ý{*data1 = uart_rec_data[2];*data2 = uart_rec_data[3];ret = 0;}uart_dec_count ++;if(uart_dec_count == 5){uart_dec_count = 0;}}return ret;
}
/* ½ÓÊÕjson×Ö·û´® */
int8_t receiveJson(RingBuff_t *ringbuff, char *str)
{static uint8_t reading,j;uint8_t readbuff,ok = 0;if(Read_RingBuff(&Uart1_RingBuff,&readbuff) == RINGBUFF_OK){if(readbuff == '{'){reading = 1;str[j++] = readbuff;ok = 0;}else if(readbuff == '}' && reading == 1){reading = 0;str[j++] = readbuff; str[j++] = '\0';ok = 1;}else if(reading == 1){str[j++] = readbuff;}else {j = 0;reading = 0;ok = 0;}}return ok;
}void usart_send(USART_TypeDef* USARTx, uint8_t*data, uint8_t len)
{uint8_t i;for(i=0;i<len;i++){while(USART_GetFlagStatus(USARTx,USART_FLAG_TC)==RESET); USART_SendData(USARTx,data[i]);}
}/**
* @brief RingBuff_Init
* @param RingBuff_t *ringbuff
* @return void
* @note ³õʼ»¯»·Ðλº³åÇø
*/
void RingBuff_Init(RingBuff_t *ringbuff)
{//³õʼ»¯Ïà¹ØÐÅÏ¢ringbuff->Head = 0;ringbuff->Tail = 0;ringbuff->Lenght = 0;
}/**
* @brief Write_RingBuff
* @param uint8_t data
* @return FLASE:»·Ðλº³åÇøÒÑÂú£¬Ð´Èëʧ°Ü;TRUE:дÈë³É¹¦
* @note Íù»·Ðλº³åÇøдÈëuint8_tÀàÐ͵ÄÊý¾Ý
*/
uint8_t Write_RingBuff(RingBuff_t *ringbuff, uint8_t data)
{if(ringbuff->Lenght >= RINGBUFF_LEN) //Åжϻº³åÇøÊÇ·ñÒÑÂú{return RINGBUFF_ERR;}ringbuff->Ring_data[ringbuff->Tail]=data;ringbuff->Tail = (ringbuff->Tail+1)%RINGBUFF_LEN;//·ÀÖ¹Ô½½ç·Ç·¨·ÃÎÊringbuff->Lenght++;return RINGBUFF_OK;
}/**
* @brief Read_RingBuff
* @param uint8_t *rData£¬ÓÃÓÚ±£´æ¶ÁÈ¡µÄÊý¾Ý
* @return FLASE:»·Ðλº³åÇøûÓÐÊý¾Ý£¬¶Áȡʧ°Ü;TRUE:¶ÁÈ¡³É¹¦
* @note ´Ó»·Ðλº³åÇø¶ÁÈ¡Ò»¸öu8ÀàÐ͵ÄÊý¾Ý
*/
uint8_t Read_RingBuff(RingBuff_t *ringbuff, uint8_t *rData)
{if(ringbuff->Lenght == 0)//ÅжϷǿÕ{return RINGBUFF_ERR;}*rData = ringbuff->Ring_data[ringbuff->Head];//ÏȽøÏȳöFIFO£¬´Ó»º³åÇøÍ·³öringbuff->Head = (ringbuff->Head+1)%RINGBUFF_LEN;//·ÀÖ¹Ô½½ç·Ç·¨·ÃÎÊringbuff->Lenght--;return RINGBUFF_OK;
}
uart.h
#ifndef __USART_H
#define __USART_H
#include "stdio.h"
#include "stm32f4xx_conf.h"
#include "sys.h" #define EN_USART1_RX 1 //ʹÄÜ£¨1£©/½ûÖ¹£¨0£©´®¿Ú1½ÓÊÕ#define RINGBUFF_LEN (100) //¶¨Òå×î´ó½ÓÊÕ×Ö½ÚÊý
#define RINGBUFF_OK 1
#define RINGBUFF_ERR 0 typedef struct
{uint16_t Head; uint16_t Tail;uint16_t Lenght;uint8_t Ring_data[RINGBUFF_LEN];
}RingBuff_t;extern uint8_t RecCoorFlag;
extern RingBuff_t Uart2_RingBuff,Uart1_RingBuff,Uart3_RingBuff;
extern uint16_t distance;void uart_init(u32 bound);
void uart2_v831_init(uint32_t bound);
void uart3_init(uint32_t bound);
void usart_send(USART_TypeDef* USARTx, uint8_t*data, uint8_t len);void RingBuff_Init(RingBuff_t *ringbuff);
uint8_t Write_RingBuff(RingBuff_t *ringbuff, uint8_t data);
uint8_t Read_RingBuff(RingBuff_t *ringbuff, uint8_t *rData);
uint8_t DataDecode(RingBuff_t *ringbuff, uint8_t *data1, uint8_t *data2);
int8_t receiveJson(RingBuff_t *ringbuff, char *str);uint16_t get_distance(void);#endif2.spi
（1）原理
SPI协议使用四个信号线进行通信：主设备的主输出（MOSI），主输入（MISO），时钟线（SCK）和片选线（SS）。
- 主设备向从设备发送数据：主设备选中一个从设备，通过片选线SS将其选中。然后，主设备通过主输出线（MOSI）将数据发送给从设备。同时，主设备通过时钟线（SCK）提供时钟信号来同步数据传输。
- 主设备接收从设备的数据：主设备向从设备发送时钟信号，从设备通过主输入线（MISO）将数据传输给主设备。
- 数据传输完成后，主设备通过将片选线（SS）拉高来释放从设备。
SPI协议支持全双工通信，意味着主设备和从设备可以同时发送和接收数据。（同步通信、全双工通信方式）
（2）实际操作和注意事项
首先设置成主机模式，然后对于的io口初始化映射即可。设置单向或者双向数据模式、设置spi的数据大小、设置时钟线空闲时候的电平状态，设置数据采样方式，设定波特率，最后使能spi。（也是和uart一样需要将数据存放到一个固定的buff中，然后对其进行下一步的处理或者运用。）我们最常用的spi也就是7zhen0.96寸的oled。
（3）代码
spi.c
void SPI1_Init(void)
{ GPIO_InitTypeDef GPIO_InitStructure;SPI_InitTypeDef SPI_InitStructure;RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);//ʹÄÜGPIOBʱÖÓRCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);//ʹÄÜSPI1ʱÖÓ//GPIOFB3,4,5³õʼ»¯ÉèÖÃGPIO_InitStructure.GPIO_Pin = GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5;//PB3~5¸´Óù¦ÄÜÊä³ö GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//¸´Óù¦ÄÜGPIO_InitStructure.GPIO_OType = GPIO_OType_PP;//ÍÆÍìÊä³öGPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;//100MHzGPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;//ÉÏÀGPIO_Init(GPIOB, &GPIO_InitStructure);//³õʼ»¯GPIO_PinAFConfig(GPIOB,GPIO_PinSource3,GPIO_AF_SPI1); //PB3¸´ÓÃΪ SPI1GPIO_PinAFConfig(GPIOB,GPIO_PinSource4,GPIO_AF_SPI1); //PB4¸´ÓÃΪ SPI1GPIO_PinAFConfig(GPIOB,GPIO_PinSource5,GPIO_AF_SPI1); //PB5¸´ÓÃΪ SPI1//ÕâÀïÖ»Õë¶ÔSPI¿Ú³õʼ»¯RCC_APB2PeriphResetCmd(RCC_APB2Periph_SPI1,ENABLE);//¸´Î»SPI1RCC_APB2PeriphResetCmd(RCC_APB2Periph_SPI1,DISABLE);//Í£Ö¹¸´Î»SPI1SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex; //ÉèÖÃSPIµ¥Ïò»òÕßË«ÏòµÄÊý¾Ýģʽ:SPIÉèÖÃΪ˫ÏßË«ÏòÈ«Ë«¹¤SPI_InitStructure.SPI_Mode = SPI_Mode_Master; //ÉèÖÃSPI¹¤×÷ģʽ:ÉèÖÃΪÖ÷SPISPI_InitStructure.SPI_DataSize = SPI_DataSize_8b; //ÉèÖÃSPIµÄÊý¾Ý´óС:SPI·¢ËͽÓÊÕ8λ֡½á¹¹SPI_InitStructure.SPI_CPOL = SPI_CPOL_High; //´®ÐÐͬ²½Ê±ÖӵĿÕÏÐ״̬Ϊ¸ßµçƽSPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge; //´®ÐÐͬ²½Ê±Öӵĵڶþ¸öÌø±äÑØ£¨ÉÏÉý»òϽµ£©Êý¾Ý±»²ÉÑùSPI_InitStructure.SPI_NSS = SPI_NSS_Soft; //NSSÐźÅÓÉÓ²¼þ£¨NSS¹Ü½Å£©»¹ÊÇÈí¼þ£¨Ê¹ÓÃSSI룩¹ÜÀí:ÄÚ²¿NSSÐźÅÓÐSSIλ¿ØÖÆSPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256; //¶¨Ò岨ÌØÂÊÔ¤·ÖƵµÄÖµ:²¨ÌØÂÊÔ¤·ÖƵֵΪ256SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB; //Ö¸¶¨Êý¾Ý´«Êä´ÓMSBλ»¹ÊÇLSBλ¿ªÊ¼:Êý¾Ý´«Êä´ÓMSBλ¿ªÊ¼SPI_InitStructure.SPI_CRCPolynomial = 7; //CRCÖµ¼ÆËãµÄ¶àÏîʽSPI_Init(SPI1, &SPI_InitStructure); //¸ù¾ÝSPI_InitStructÖÐÖ¸¶¨µÄ²ÎÊý³õʼ»¯ÍâÉèSPIx¼Ä´æÆ÷SPI_Cmd(SPI1, ENABLE); //ʹÄÜSPIÍâÉèSPI1_ReadWriteByte(0xff);//Æô¶¯´«Êä
}
//SPI1ËÙ¶ÈÉèÖú¯Êý
//SPIËÙ¶È=fAPB2/·ÖƵϵÊý
//@ref SPI_BaudRate_Prescaler:SPI_BaudRatePrescaler_2~SPI_BaudRatePrescaler_256
//fAPB2ʱÖÓÒ»°ãΪ84Mhz£º
void SPI1_SetSpeed(u8 SPI_BaudRatePrescaler)
{assert_param(IS_SPI_BAUDRATE_PRESCALER(SPI_BaudRatePrescaler));//ÅжÏÓÐЧÐÔSPI1->CR1&=0XFFC7;//λ3-5ÇåÁ㣬ÓÃÀ´ÉèÖò¨ÌØÂÊSPI1->CR1|=SPI_BaudRatePrescaler; //ÉèÖÃSPI1ËÙ¶È SPI_Cmd(SPI1,ENABLE); //ʹÄÜSPI1
}
//SPI1 ¶Áдһ¸ö×Ö½Ú
//TxData:ҪдÈëµÄ×Ö½Ú
//·µ»ØÖµ:¶ÁÈ¡µ½µÄ×Ö½Ú
u8 SPI1_ReadWriteByte(u8 TxData)
{ while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET){}//µÈ´ý·¢ËÍÇø¿Õ SPI_I2S_SendData(SPI1, TxData); //ͨ¹ýÍâÉèSPIx·¢ËÍÒ»¸öbyte Êý¾Ýwhile (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET){} //µÈ´ý½ÓÊÕÍêÒ»¸öbyte return SPI_I2S_ReceiveData(SPI1); //·µ»Øͨ¹ýSPIx×î½ü½ÓÊÕµÄÊý¾Ý }spi.h
#ifndef __SPI_H
#define __SPI_H
#include "sys.h"void SPI1_Init(void); //³õʼ»¯SPI1¿Ú
void SPI1_SetSpeed(u8 SpeedSet); //ÉèÖÃSPI1ËÙ¶È
u8 SPI1_ReadWriteByte(u8 TxData);//SPI1×ÜÏ߶Áдһ¸ö×Ö½Ú#endif3.i2c
(1)原理
I2C 是一种串行通信协议，用于连接微控制器或其他集成电路之间的通信。I2C协议使用两个信号线进行通信：串行数据线（SDA）和串行时钟线（SCL）。
I2C的工作原理如下：
- 主设备发送数据：主设备先发送起始信号，即将SDA从高电平拉低，然后再将SCL拉高。接着，主设备通过SDA线发送地址和数据位，每一位都在SCL的上升沿或下降沿进行采样。
- 从设备接收数据：从设备在SCL的上升沿或下降沿采样SDA线上的数据位。
- 主设备接收数据：主设备将SDA线拉低并将SCL线拉高，从设备将数据位写到SDA线上。接着，主设备在SCL的上升沿或下降沿采样数据位。
- 数据传输完成后，主设备发送停止信号，即将SDA从低电平拉高，然后再将SCL拉高。
I2C协议支持多主设备，即多个主设备可以在总线上进行通信。每个设备都有唯一的地址，主设备通过地址选择要与之通信的设备。I2C协议的传输速度相对较慢，但适用于短距离通信。
（2）日常的使用
首先i2c分为软件I2C和硬件I2C在一般的日常使用是使用软件i2c，因为I2C不能连接太多的设备，不存在像spi那么多的io口，只有数据线和时钟线，软件代码部分就相对复杂一点。最开始还是需要io初始化映射，然后设置I2C的开始和停止信号，设置应答信号，最后进行数据的发送接收。
（3）代码
MPUIIC.C
#include "mpuiic.h"
#include "delay.h"//MPU IIC ÑÓʱº¯Êý
void MPU_IIC_Delay(void)
{delay_us(2);
}//³õʼ»¯IIC
void MPU_IIC_Init(void)
{ GPIO_InitTypeDef GPIO_InitStructure;RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE);//ÏÈʹÄÜÍâÉèIO PORTBʱÖÓ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1|GPIO_Pin_0; // ¶Ë¿ÚÅäÖÃGPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT; //ÍÆÍìÊä³öGPIO_InitStructure.GPIO_OType = GPIO_OType_PP;GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //IO¿ÚËÙ¶ÈΪ50MHzGPIO_Init(GPIOA, &GPIO_InitStructure); //¸ù¾ÝÉ趨²ÎÊý³õʼ»¯GPIO GPIO_SetBits(GPIOA,GPIO_Pin_1|GPIO_Pin_0); }
//²úÉúIICÆðʼÐźÅ
void MPU_IIC_Start(void)
{MPU_SDA_OUT(); //sdaÏßÊä³öMPU_IIC_SDA=1; MPU_IIC_SCL=1;MPU_IIC_Delay();MPU_IIC_SDA=0;//START:when CLK is high,DATA change form high to low MPU_IIC_Delay();MPU_IIC_SCL=0;//ǯסI2C×ÜÏߣ¬×¼±¸·¢ËÍ»ò½ÓÊÕÊý¾Ý
}
//²úÉúIICÍ£Ö¹ÐźÅ
void MPU_IIC_Stop(void)
{MPU_SDA_OUT();//sdaÏßÊä³öMPU_IIC_SCL=0;MPU_IIC_SDA=0;//STOP:when CLK is high DATA change form low to highMPU_IIC_Delay();MPU_IIC_SCL=1; MPU_IIC_SDA=1;//·¢ËÍI2C×ÜÏß½áÊøÐźÅMPU_IIC_Delay();
}
//µÈ´ýÓ¦´ðÐźŵ½À´
//·µ»ØÖµ£º1£¬½ÓÊÕÓ¦´ðʧ°Ü
// 0£¬½ÓÊÕÓ¦´ð³É¹¦
u8 MPU_IIC_Wait_Ack(void)
{u8 ucErrTime=0;MPU_SDA_IN(); //SDAÉèÖÃΪÊäÈë MPU_IIC_SDA=1;MPU_IIC_Delay(); MPU_IIC_SCL=1;MPU_IIC_Delay(); while(MPU_READ_SDA){ucErrTime++;if(ucErrTime>250){MPU_IIC_Stop();return 1;}}MPU_IIC_SCL=0;//ʱÖÓÊä³ö0 return 0;
}
//²úÉúACKÓ¦´ð
void MPU_IIC_Ack(void)
{MPU_IIC_SCL=0;MPU_SDA_OUT();MPU_IIC_SDA=0;MPU_IIC_Delay();MPU_IIC_SCL=1;MPU_IIC_Delay();MPU_IIC_SCL=0;
}
//²»²úÉúACKÓ¦´ð
void MPU_IIC_NAck(void)
{MPU_IIC_SCL=0;MPU_SDA_OUT();MPU_IIC_SDA=1;MPU_IIC_Delay();MPU_IIC_SCL=1;MPU_IIC_Delay();MPU_IIC_SCL=0;
}
//IIC·¢ËÍÒ»¸ö×Ö½Ú
//·µ»Ø´Ó»úÓÐÎÞÓ¦´ð
//1£¬ÓÐÓ¦´ð
//0£¬ÎÞÓ¦´ð
void MPU_IIC_Send_Byte(u8 txd)
{ u8 t; MPU_SDA_OUT(); MPU_IIC_SCL=0;//ÀµÍʱÖÓ¿ªÊ¼Êý¾Ý´«Êäfor(t=0;t<8;t++){ MPU_IIC_SDA=(txd&0x80)>>7;txd<<=1; MPU_IIC_SCL=1;MPU_IIC_Delay(); MPU_IIC_SCL=0; MPU_IIC_Delay();}
}
//¶Á1¸ö×Ö½Ú£¬ack=1ʱ£¬·¢ËÍACK£¬ack=0£¬·¢ËÍnACK
u8 MPU_IIC_Read_Byte(unsigned char ack)
{unsigned char i,receive=0;MPU_SDA_IN();//SDAÉèÖÃΪÊäÈëfor(i=0;i<8;i++ ){MPU_IIC_SCL=0; MPU_IIC_Delay();MPU_IIC_SCL=1;receive<<=1;if(MPU_READ_SDA)receive++; MPU_IIC_Delay(); } if (!ack)MPU_IIC_NAck();//·¢ËÍnACKelseMPU_IIC_Ack(); //·¢ËÍACK return receive;
}MPUIIC.H
#ifndef __MPUIIC_H
#define __MPUIIC_H
#include "sys.h"
/
//IO·½ÏòÉèÖÃ#define MPU_SDA_IN() {GPIOA->MODER&=~(3<<(1*2));GPIOA->MODER|=0<<1*2;} //PA1ÊäÈëģʽ
#define MPU_SDA_OUT() {GPIOA->MODER&=~(3<<(1*2));GPIOA->MODER|=1<<1*2;} //PA1Êä³öģʽ//IO²Ù×÷º¯Êý
#define MPU_IIC_SCL PAout(0) //SCL
#define MPU_IIC_SDA PAout(1) //SDA
#define MPU_READ_SDA PAin(1) //SDA //IICËùÓвÙ×÷º¯Êý
void MPU_IIC_Delay(void); //MPU IICÑÓʱº¯Êý
void MPU_IIC_Init(void); //³õʼ»¯IICµÄIO¿Ú
void MPU_IIC_Start(void); //·¢ËÍIIC¿ªÊ¼ÐźÅ
void MPU_IIC_Stop(void); //·¢ËÍIICÍ£Ö¹ÐźÅ
void MPU_IIC_Send_Byte(u8 txd); //IIC·¢ËÍÒ»¸ö×Ö½Ú
u8 MPU_IIC_Read_Byte(unsigned char ack);//IIC¶ÁÈ¡Ò»¸ö×Ö½Ú
u8 MPU_IIC_Wait_Ack(void); //IICµÈ´ýACKÐźÅ
void MPU_IIC_Ack(void); //IIC·¢ËÍACKÐźÅ
void MPU_IIC_NAck(void); //IIC²»·¢ËÍACKÐźÅvoid IMPU_IC_Write_One_Byte(u8 daddr,u8 addr,u8 data);
u8 MPU_IIC_Read_One_Byte(u8 daddr,u8 addr); #endif
