2021年03月11日 | STM32的i2c容易出的问题 和l3g4200d例程

调试了一晚上，终于一点点把stm32可怕的i2c消灭了，这里分享一下遇到的问题。

最严重的一次卡住居然是在这句话上

/* Send START condition */

I2C_GenerateSTART(I2C1, ENABLE);

/* Test on EV5 and clear it */

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

执行到第二句就怎么也过不去了，后来才很气愤的发现这是stm32的硬件bug，把fsmc关掉才能使用i2c1的非重影射引脚，关掉以后一切正常。害得我干瞪了两个小时屏幕。

第二次被卡住是在

I2C_Send7bitAddress(I2C1, 0xD2, I2C_Direction_Transmitter);

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

错误的原因是传输的地址要左移一位。虽然地址是7位的，但是必须在后面而不是前面补零，变成8位地址再传递。

第三次是在

I2C_GenerateSTOP(I2C1, ENABLE);//产生 I2Cx传输 STOP条件

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));

原因是必须要先产生终止再检查数据。仔细读手册就解决了这个问题

已经凌晨一点了，终于长舒一口气。这里把代码贴上来，是一个调试陀螺仪l3g4200d的程序，直接调用GYRO_Test()即可，但是必须先调用GYRO_Init()，初始化GPIO和RCC，并添加相应的头文件。

#define WHO_AM_I 0x0F

#define CTRL_REG1 0x20

#define CTRL_REG2 0x21

#define CTRL_REG3 0x22

#define CTRL_REG4 0x23

#define CTRL_REG5 0x24

#define REFERENCE 0x25

#define OUT_TEMP 0x26

#define STATUS_REG 0x27

#define OUT_X_L 0x28

#define OUT_X_H 0x29

#define OUT_Y_L 0x2A

#define OUT_Y_H 0x2B

#define OUT_Z_L 0x2C

#define OUT_Z_H 0x2D

#define FIFO_CTRL_REG 0x2E

#define FIFO_SRC_REG 0x2F

#define INT1_CFG 0x30

#define INT1_SRC 0x31

#define INT1_TSH_XH 0x32

#define INT1_TSH_XL 0x33

#define INT1_TSH_YH 0x34

#define INT1_TSH_YL 0x35

#define INT1_TSH_ZH 0x36

#define INT1_TSH_ZL 0x37

#define INT1_DURATION 0x38

void I2C_Configuration(void)

{

I2C_InitTypeDef I2C_InitStructure;

I2C_DeInit(I2C1);

/* I2C configuration */

I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;

I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;

I2C_InitStructure.I2C_OwnAddress1 = 0xD2;

I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;

I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;

I2C_InitStructure.I2C_ClockSpeed = 400000;

/* I2C Peripheral Enable */

I2C_Cmd(I2C1, ENABLE);

/* Apply I2C configuration after enabling it */

I2C_Init(I2C1, &I2C_InitStructure);

}

void GYRO_Write(INT8U addr, INT8U data)//write a byte to gyroscope

{

int dummy;

/* Send STRAT condition */

I2C_GenerateSTART(I2C1, ENABLE);

/* Test on EV5 and clear it */

while(I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT) != SUCCESS);

/* Send EEPROM address for write */

dummy=I2C1->SR1;

I2C_Send7bitAddress(I2C1, 0xD2, I2C_Direction_Transmitter);

/* Test on EV6 and clear it */

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

/* Send the EEPROM's internal address to write to */

I2C_SendData(I2C1, addr);

/* Test on EV8 and clear it */

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

/* Send the byte to be written */

I2C_SendData(I2C1, data);

/* Test on EV8 and clear it */

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

/* Send STOP condition */

I2C_GenerateSTOP(I2C1, ENABLE);

}

INT8U GYRO_Read(INT8U addr)//read a byte from gyroscope

{

INT8U data;

/* Send START condition */

I2C_GenerateSTART(I2C1, ENABLE);

/* Test on EV5 and clear it */

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

/* In the case of a single data transfer disable ACK before reading the data */

I2C_AcknowledgeConfig(I2C1, DISABLE);

/* Send EEPROM address for write */

I2C_Send7bitAddress(I2C1, 0xD2, I2C_Direction_Transmitter);

/* Test on EV6 and clear it */

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

/* Send the EEPROM's internal address to write to */

I2C_SendData(I2C1, addr);

/* Test on EV8 and clear it */

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

/* Send STRAT condition a second time */

I2C_GenerateSTART(I2C1, ENABLE);

/* Test on EV5 and clear it */

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

/* Send EEPROM address for read */

I2C_Send7bitAddress(I2C1, 0xD2, I2C_Direction_Receiver);

/* Test on EV6 and clear it */

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));

/* Send STOP Condition */

I2C_GenerateSTOP(I2C1, ENABLE);

/* Test on EV7 and clear it */

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));

/* Read a byte from the EEPROM */

data = I2C_ReceiveData(I2C1);

return data;

}

void GYRO_Init(){

I2C_Configuration();

GYRO_Write(CTRL_REG1, 0xEF);

GYRO_Write(CTRL_REG2, 0x00);

GYRO_Write(CTRL_REG3, 0x08);

GYRO_Write(CTRL_REG4, 0x10);

GYRO_Write(CTRL_REG5, 0x00);

}

void GYRO_Test(){

int value1=0,value2=0,value3=0;

value1= GYRO_Read(OUT_X_H)*0x100 + GYRO_Read(OUT_X_L);

if(value1 > 0x7FFF)

value1=value1-0x10000;

value2= GYRO_Read(OUT_Y_H)*0x100 + GYRO_Read(OUT_Y_L);

if(value2 > 0x7FFF)

value2=value2-0x10000;

value3= GYRO_Read(OUT_Z_H)*0x100 + GYRO_Read(OUT_Z_L);

if(value3 > 0x7FFF)

value3=value3-0x10000;

printf("%d %d %dn",value1,value2,value3);

}

运行结果（串口接到的部分数据）：

20 33 -51

16 15 -60

19 36 -74

51 -227 -29

-6 34 -32

23 -252 -61

5 26 -40

16 36 -75

34 48 -52

-2 27 -35