Posted on January 02, 2014 at 18:26Hello everyone. I probably have some usual problem about i2c communication. Namely, I have the following code and trying to read MPU6050 WHO_AM_I register(http://www.invensense.com/mems/gyro/mpu6050.html). The address of MPU6050 is 0x68 << 1(0xD0) but when i try to read it i stuck at
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
The whole code is given:
//#include ''MPU6050.h''
#include ''stm32f4xx_i2c.h''
#include ''stm32f4xx_gpio.h''
#include ''stm32f4xx_rcc.h''
//int16_t AccelGyro[6]={0};
int main()
{
int i = 0;
GPIO_InitTypeDef GPIO_InitStruct;
I2C_InitTypeDef I2C_InitStruct;
u8* pBuffer;
// enable clock for SCL and SDA pins
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
// enable APB1 peripheral clock for I2C1
RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9; // we are going to use PB6 and PB7
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF; // set pins to alternate function
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz; // set GPIO speed
GPIO_InitStruct.GPIO_OType = GPIO_OType_OD; // set output to open drain --> the line has to be only pulled low, not driven high
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP; // enable pull up resistors
GPIO_Init(GPIOB, &GPIO_InitStruct); // init GPIOB
// Connect I2C1 pins to AF
GPIO_PinAFConfig(GPIOB, GPIO_PinSource8, GPIO_AF_I2C1); // SCL
GPIO_PinAFConfig(GPIOB, GPIO_PinSource9, GPIO_AF_I2C1); // SDA
// configure I2C1
I2C_InitStruct.I2C_ClockSpeed = 100000; // 100kHz
I2C_InitStruct.I2C_Mode = I2C_Mode_I2C; // I2C mode
I2C_InitStruct.I2C_DutyCycle = I2C_DutyCycle_2; // 50% duty cycle --> standard
I2C_InitStruct.I2C_OwnAddress1 = 0x00; // own address, not relevant in master mode
I2C_InitStruct.I2C_Ack = I2C_Ack_Enable; // disable acknowledge when reading (can be changed later on)
I2C_InitStruct.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_10bit; // set address length to 7 bit addresses
I2C_Init(I2C1, &I2C_InitStruct); // init I2C1
// enable I2C1
I2C_Cmd(I2C1, ENABLE);
/* While the bus is busy */
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY));
/* Send START condition */
I2C_GenerateSTART(I2C1, ENABLE);
/* Test on EV5 and clear it */
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
/* Send MPU6050 address for write */
I2C_Send7bitAddress(I2C1, 0xD0, I2C_Direction_Transmitter);
/* Test on EV6 and clear it */
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
/* Clear EV6 by setting again the PE bit */
I2C_Cmd(I2C1, ENABLE);
/* Send the MPU6050's internal address to write to */
I2C_SendData(I2C1, 0x75);
/* 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 MPU6050 address for read */
I2C_Send7bitAddress(I2C1, 0xD1, I2C_Direction_Receiver);
/* Test on EV6 and clear it */
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));
