[General] CCS811 Hardware ID reading issues

[nikhilsukhdev]

Hi, I have been working with the CCS811 for a while now. I have interfaced the sensor to the STM-32 L1072 chipset. While trying to read the hardware ID from the HW_ID register addressed at 0x20, I am getting a value as 0x80 instead of 0x81. I am using I2c for communication between the sensor and the microcontroller. Is there anything that I am missing? Could somebody please help me out with this issue?

 

[KlausST]

Hi,

How do you think we can help you?
We have nothing to verify.

What about giving informations that we can verify, like
* code
* schematic
* flow chart
* scope pictures of I2C signals
...

Klaus

 

[nishant_sahay]

Hi,

How do you think we can help you?
We have nothing to verify.

What about giving informations that we can verify, like
* code
* schematic
* flow chart
* scope pictures of I2C signals
...

Klaus

On the serial monitor we are getting the ID as 0x80 but, on CRO the hardware ID it 0x81, with a gap between the 8th and 9th pulse, and we are missing the NAK signal as specified in the Application Note.

We are currently using this function to read the register 0x20:

HAL_I2C_Mem_Read(&hi2c1, CCS811_ADDRD, CCS811_HW_ID, SIZE_1, RD_buf, SIZE_1, I2C_TIMEOUT);
// CCS811_ADDRD = 0xB5
// CCS811_HW_ID = 0x20

 

[nishant_sahay]

Issue in using I2C Protocol while reading Hardware ID of CCS811

Hi ,
I am integrating CCS811 with STM32L072xx. I am reading the Hardware ID of it, so for the same I am monitoring the clock pulses on the SCL line. When the Hardware ID has to be received on SDA line, there is a gap between 8th and 9th pulse for the same in the SCL line. What can be the issue for that?

 

[KlausST]

Re: Issue in using I2C Protocol while reading Hardware ID of CCS811

Hi,

The gap is no problem ... I'm rather sure it is within specification. In doubt read the specification.
Mind: This is not an "asynchronous" interface, thus you don't need a known and fixed bit rate.

But I recommend to use a lower ohmic pullup at both lines ... your rise time is rather high.

Klaus