STM32F746 - DISCO I2C HAL_TIMEOUT

Question

I am attempting to implement I2C interface on the STM32F7-Discovery Board using the a VEML 6070 UV light sensor (https://www.vishay.com/docs/84277/veml6070.pdf).

The 7-bit slave address for the device is 0x38. The addresses for data access are 0x71(LSB) and 0x73(MSB)

I am not able to write or read any data from the master. When I check the HAL_Status it returns HAL_Timeout.

Some of my code is shown below:

EDIT:

void VEML6070_Init(void){

char data[1];

HAL_I2C_Master_Receive(&hi2c1, 0x18<<1, data, 1, 150); 

data[0] = 0x06;

HAL_I2C_Master_Transmit(&hi2c1, 0x38<<1, data, 1, 150);

}

int main(void)  {  
 unsigned int rawUV;
 char lcd_buf[5]
 uint8_t address[1];
 uint8_t MSBdata[1];
 uint8_t LSBdata[1];
 SystemClock_Config();
 MX_I2C1_Init();
 MX_GPIO_Init();

 VEML6070_Init();

 address[0] = 0x02;

 HAL_I2C_Mem_Write(&hi2c1, 0x38<<1, 0x70, I2C_MEMADD_SIZE_8BIT, address, 1, 150)

 HAL_I2C_Mem_Read(&hi2c1, 0x38<<1, 0x73, I2C_MEMADD_SIZE_8BIT, MSBdata, 1, 150)

 HAL_I2C_Mem_Read(&hi2c1, 0x38<<1, 0x71, I2C_MEMADD_SIZE_8BIT, LSBdata, 1, 150)

 rawUV = MSBdata[0]<<8 | LSBdata[0];
 sprintf(lcd_buf, "%d ", rawUV);
 //GLCD_DrawString (0, 7*24, lcd_buf);
}

Does anybody have experience of implementing I2C with the STM32F7 boards, and if so are you able to shed any light on why I may be getting 'HAL_TIMEOUT'? Is it a case of me using the wrong register addresses, or is it something more complex?

Thanks.

Edit:

I have now altered the code to use the correct protocol, but I am still finding a 'HAL_TIMEOUT'.

HAL_I2C_Master_Transmit(&hi2c1, 0x38<<1, address, 1, 150);

HAL_I2C_Master_Receive(&hi2c1, 0x39<<1, MSBdata, 1, 150);

HAL_I2C_Master_Receive(&hi2c1, 0x38<<1, LSBdata, 1, 150);

Any other suggestions?

Answer 1

The protocol is wrong. It is not register based to a single slave address so you can't use the Mem_Write and Mem_Read functions. What you have is there are three different slave addresses for single byte for command, MSB and LSB data.