SGP40 sensor

[er3481]

Hi

I am trying to read the SGP40 VOC sensor with the code below, but i can't read the raw data. I can transmit the command but when i try to receive data, it can not receive. I am using STM32F103 mcu. Any advise .

uint8_t SGP40_ReadVOC(void)
{
 uint8_t cmd[2] = {0x26, 0x0F}; 
 uint8_t rx_buf[6];
 uint16_t voc_raw = 0;

 HAL_Delay(250); 

 if (HAL_I2C_Master_Transmit(&hi2c1, 0xB2, cmd, 2, HAL_MAX_DELAY) != HAL_OK)
 { 
 return 0xFF;
 }

 HAL_Delay(30); 

 if (HAL_I2C_Master_Receive(&hi2c1, 0xB3, rx_buf, 6, HAL_MAX_DELAY) != HAL_OK)
 { 
 return 0xFF;
 }

 voc_raw = (rx_buf[0] << 8) | rx_buf[1];

 return voc_raw >> 8; 
}

 

[Andrew Neil]

---

@er3481 wrote:

the SGP40 VOC sensor

---

You mean this: https://sensirion.com/products/catalog/SGP40 ?

 

Please give details of your hardware; show schematics.

Have you looked at the I2C lines with an oscilloscope and/or analyser to see what - if anything - is happening?

 

Are you sure you have the correct I2C address, and correctly shifted as HAL requires?