mc33772c assign CIDs

[kevinyuee]

Hi,
    I am currently connecting the mc33664 and then the mc33772c through the mcu, I am currently in the mode of connecting mc33664 and then mc33772c through the mcu. Now, I can get the correct response by sending the instruction to read the init register, but after I tried to write the cid and read it, I failed to get the correct response.
   Is it normal that I keep sending without changing the read instruction (without modifying the message counter) and still get a response.

kevinyuee_0-1752547683334.png

    The following is a situation where I attempted to write the cid but received no response, while reading the init register also got a response. Moreover, other instructions sent thereafter can also receive the same response, unless an instruction to read the init register is sent here again, in which case the response data will be updated.

kevinyuee_1-1752547826969.png

[JozefKozon]

Hi Kevinyuee,

INIT Register Read Works

• This suggests that the default CID (usually 0x00) is still active.
• The message counter and CRC are likely correct for this command.

Writing the CID requires:

• A valid message counter (incremented from the last successful message).
• A correct CRC.
• The correct frame format for the CID assignment command.

Please refer to the sections 9.3.2 and 9.3.3 in the full MC33772C full datasheet, for description of the Idle and Init modes. 

With Best Regards,

Jozef

[kevinyuee]

Hi,

  I power the mc33772c through wiring. Will this method affect my reading and writing of the mc33772c chip, assign CIDs.

kevinyuee_0-1752649773184.png

[JozefKozon]

Hi Kevin,

yes, this might be the reason. Please refer to the section 5.2 in the MC33772C datasheet. Depending which MC33772C version you are using, there is a minimum number of Cells which must be connected to the BCC (Battery Cell Controller). Usually minimum number of Cells is 3. However even for the MC33772CTC0AE version, the CT and CB pins cannot be left floating.

JozefKozon_0-1752653968155.png

Please also refer to the AN12536. 

JozefKozon_1-1752654057536.png

With Best Regards,

Jozef

[kevinyuee]

Hi,
    I have connected the battery now, but still can't write the cid successfully. And by reading the FAULT1 STATUS$24 register, I observe that there is also fault detection after I execute the write instruction. I don't have an external EEPROM, so setting I2C ERR FLT to 1 should be normal.
    My waveform is also normal. I really don't know why it can't be written correctly.

image.png

kevinyuee_0-1752751832970.png

[JozefKozon]

Hi Kevin,

are you using our Evaluation boards? If yes, please state the full product numbers. If you are using your own design, please share your schematic with voltage levels and part values to check.

With Best Regards,

Jozef

[kevinyuee]

Hi,
   I have sent the schematic diagram as an attachment to your private message last Friday.Have you received it? Are there any questions?
Best wish
Kevin

[JozefKozon]

Hi Kevin,

thank you for the schematic. Yes, I have received it. I will check it and I will come back.

With Best Regards,

Jozef

[JozefKozon · Accepted solution]

Hi Kevin,

I have checked your schematic, it seems to be correct. However I don't see how the individual BCC grounds are connected. Please make sure, that the BCC grounds are connected to the negative pole of the lowest Cell in the 6 Cell battery. Please refer to the schematic attached. 

JozefKozon_0-1753077984635.png

JozefKozon_1-1753077999631.png

If the EEPROM is not present, the I2C ERR FLT should be ignored.

For start, please disconnect the higher BCCs and try to write only to the first BCC, with the 6 Cell battery connected to only the first BCC. Something as below.

JozefKozon_2-1753078569430.png

With Best Regards,

Jozef