Why HAL_I2C_Mem_Read returns only 0?

[ATavo.1]

Hi,

I am using stm32f1 and HUT21D sensor (Temperature and humidity sensor). The sensor use i2c for communication.

I am using IAR and cubeMX.

For cube: I used default setting for i2c.

For IAR: I shared the main.c below.

Can anyone help on why only get 0.

#I2C​ #[STM32 MCUs]​ 

[Tesla DeLorean]

Does the function return an error or success code?

If HTU21D_RX_DATA is filled with a different data pattern, does it return that?

That would be indicative that the device is not responding.

Check wiring, pins used, pull-ups, and slave address

[Tesla DeLorean]

Slave address, and register address look correct, is it timing out, or not responding at all?

Have you scoped the pins?

[ATavo.1]

I used the debug and I didn't get any errors and I only get zero.I checked the pull-ups and the slave address is 0x40.

It seems okay.

The data sheet for the sensor is attached below.

[Tesla DeLorean]

The array defaults would be zero.

Any other registers in the part readable?

[ATavo.1]

sadly no.

[MFran.4]

Scoping the pins is a good idea.

What does HAL_I2C_MemRead return as status? (stat = HAL_I2C_Memread(...) )

[ATavo.1]

I

[ATavo.1]

It show HAL_ERROR

[ATavo.1]

It works fine. No timing out or any error in debug but the return of the HAL_I2C_Mem_Read is HAL_Error.