I2C Slave Address Set Problem

[Omerbzkt]

I'm trying to read data from my I2C sensor, the MLX90614 sensor, using a STM32F411CEU6. When I examined the MLX90614 datasheet, I saw that the I2C clock speed should be a maximum of 100kHz and I configured the clock accordingly. However, after the start condition is set, although I write the slave address to the I2C_DR register, I cannot get the address set flag. I leave the code I wrote below. Thank you if you help. Enjoy your work.

[Omerbzkt]

Duplicate - merged.

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I'm trying to read data from my I2C sensor, the MLX90614 sensor, using a STM32F411CEU6. When I examined the MLX90614 datasheet, I saw that the I2C clock speed should be a maximum of 100kHz and I configured the clock accordingly. However, after the start condition is set, although I write the slave address to the I2C_DR register, I cannot get the address set flag. I leave the code I wrote below. Thank you if you help. Enjoy your work.

[Techn]

May be you can try with HAL libraries to program, so that the error detection is easier. Once logic is fully established you can test your register based prigramming. 

[padawan]

Hi,

The code is difficult to read. Why don't you use the HAL_functions for the first tests?
About the hardware: 1st question are the pullups available? The internal pullup of the ports is not sufficient. (should be about 3k3).
The Melexis sends 3 bytes when reading.

i have a little different sensor (MLX90615)

 

 

I2C_HandleTypeDef *_i2c = &hi2c1;// your i2c port
uint8_t _adr = 0xB4;
uint8_t _ret =0xFF;
_ret= (HAL_I2C_IsDeviceReady(_i2c,_adr,3,200) == HAL_OK);

 

Code as example, not testet.

 

int16_t	mlx90615::getID(uint8_t addr)
{


	uint16_t _ret= 0xFFFF;
	uint8_t _rbuff[5]={0,0,0,0,0};
	uint8_t _sbuff = 0x1C; // MLX_regID1
	HAL_StatusTypeDef _Hal;

	_Hal=(HAL_I2C_Mem_Read (_i2c, addr, _sbuff ,I2C_MEMADD_SIZE_8BIT,_rbuff,5,100));
		if (_Hal==HAL_OK)
			{
			_ret = ((_rbuff[1]<<8)& (_rbuff[0]));
			}

		return _ret;

}

 

May be this helps.

padawan