HDC3021-Q1: 0x37 0x81, Manufacturer ID I2C read fails

Jay Fetter

Prodigy 20 points

Part Number: HDC3021-Q1

Hi,

Trying to read from the manufacturer ID register seems to cause the I2C bus to hang.

Other register are working as expected.

Any thoughts?

5 months ago

0 Alex Thompson 5 months ago

TI__Expert 5670 points

Jay,

Are you discarding the CRC that is returned after reading the manufacturer ID by issuing a NACK before the CRC is given?

Regards

-Alex

0 Jay Fetter 5 months ago in reply to Alex Thompson

Prodigy 20 points

This is what my software team sent me:

So it looks like the NACK is there.

+1 Alex Thompson 5 months ago in reply to Jay Fetter

TI__Expert 5670 points

Jay,

Please try not issuing the NACK before the CRC is delivered, and accepting it. Then when the CRC is accepted, the NACK can be issued to end the read transaction. I am aware that the datasheet says that a user can use a NACK to disregard the CRC, but we have since learned that not accepting the returned CRC can cause a bug which holds the I2C bus low and wont let it go. We are in the process of correcting the datasheet.

Accepting the CRC should fix your issue.

Thanks

-Alex Thompson

Sensors

Sensors forum

HDC3021-Q1: 0x37 0x81, Manufacturer ID I2C read fails