TMAG5273: need to read out a multiple of four registers to get a CRC?

Jonathan Navor

Genius 9475 points

Part Number: TMAG5273

Hi Team,

Kindly help us check our customer's concerns below.

I'm working with the TMAG5273 LowPower Linear 3D Hall Effect Sensor at the moment and have a question regarding CRC.

is it true, that I only get a CRC back if a read out at least 4 bytes?

hen I read out 3 bytes - 2 register bytes and the 3. byte I assumed would be the CRC, I don't get a CRC but a 3rd register byte (consecutive read). but if I read out 5 bytes, I get 4 register bytes, and the 5th byte the CRC.

I get a CRC at the correct position, whenever I read out 5 bytes (5 bytes read out --> 4 register bytes + 1 byte CRC).

Basically every 4 bytes I get a CRC. But I don't get a CRC if I only ready out 3 bytes. Instead of 2 register bytes + 1 byte CRC, I get 3 register bytes. When I read out 10 bytes, I get a CRC byte after every 4 bytes.

Therefore my question is, do I need to read out a multiple of four registers to get a CRC?

Best regards,

Jonathan

over 3 years ago

0 Alicia Rosenberger over 3 years ago

TI__Genius 14420 points

Hi Jonathan,

Do you know what kind of I2C read command your customer is using (Standard 3-Byte I2C Read, I2C Read Command for 16-Bit Data, I2C Read Command for 8-Bit Data)?

Best,

~Alicia

0 Roland Wiget over 3 years ago in reply to Alicia Rosenberger

Prodigy 30 points

Hi Alicia

We are using the Standard 3-Byte I2C Read command

0 Alicia Rosenberger over 3 years ago in reply to Roland Wiget

TI__Genius 14420 points

Hi Roland,

Thanks for clarifying. I am not sure if you noticed on page 18 of the datasheet, but the TMAG5273 requires 4 bytes of data to be read before generating a CRC byte. Standard 3-byte I2C is not supported for CRC. I have included a snippet from the datasheet below:

Let me know if you have any questions!

Best,

~Alicia

0 Roland Wiget over 3 years ago in reply to Alicia Rosenberger

Prodigy 30 points

Hi Alicia

Thanks for clarification. I did read that, but didn't get that it is not possible for less than 4 bytes. Anyway, standard 3-byte read command with crc works, if I read out 5 bytes (4 register bytes and 1 byte crc). Knowing that 4 bytes of data to be read out are required, helps to know, that we do the reading correctly :).

Thank you for your help

Best regards

Roland

Sensors

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TMAG5273: need to read out a multiple of four registers to get a CRC?