BQ76952: BQ76952 the first command sent through IIC after power-on returns NACK

Star Xu

Part Number: BQ76952

The first instruction sent through IIC after power-on returns NACK, and subsequent instructions are normal.

The normal timing is that after the host sends 0X3E, 76952 replies with ACK, as follows:

The error is as follows:

The error occurs when the command is sent for the first time after power-on. After the error is restored, the command sent after the bus is restored is normal.

The query is why the command for the first time after power-on is wrong. No matter how long I delay sending the command, the first command All errors will occur.

Thanks

Star

over 1 year ago

0 Max Verboncoeur over 1 year ago

TI__Mastermind 25880 points

Hi Star,

Does this occur with other commands, or only with the sequence you have captured above?

Regards,

Max Verboncoeur

0 Star Xu over 1 year ago in reply to Max Verboncoeur

TI__Genius 9645 points

Hi Max

Thanks for your reply.

The first command enters configmode and returns NACK.

Send the same command after 500ms and reply normally.

After power on, send a command to read the device name and reply NACK.

Send the same command after 500ms and reply normally.

Thanks

Star

+1 Max Verboncoeur over 1 year ago in reply to Star Xu

TI__Mastermind 25880 points

Hi Star,

I found this thread that details a similar issue: BQ76952: I2C Communication errors / Communication error received over time - Power management forum - Power management - TI E2E support forums.

You may try following the advice given in that thread and see if any of it works.

You may also try sending a direct command such as the Cell 1 Voltage command (see below for the example from the SDG) to see if the device responds differently.

Regards,

Max Verboncoeur