BQ78Z100: transaciton time of BQ78Z100

1. to ensure you get the correct results that wait time is needed.

2. the results you read back being correct is how to check

thanks

Onyx

Hi Onyx-san,

Thank you for the reply. He is my customer.

In his system, BQ78Z100 and TMS570 are tied with I2C. He sees some I2C communication error even when the interval is 100ms. He says as longer interval, the number of error gets smaller.

1. Could you please let us know how the communication error happens when the interval is too short?

2. Could you please tell us theory or equation which may helps customer determine their interval? Asking because they don't want to determine the interval based on their heat run.

Regards,

Itoh

1.pls see section 10.3.2 of the document below:

http://www.ti.com/lit/ug/sluub65a/sluub65a.pdf 

typically depending on the speed of the line, there might be a need to increase the delay to avoid getting garbage data.

2. Usually, by trial and error to find a sweet spot that works

thanks

Onyx

Hi Onyx-san,

Why do you recommend me to read BQ27542 RTM? Does it have same architecture as BQ78Z100? My customer says BQ78Z100 TRM does not have description about I2C interval. How are they related each other?

Regards,

Itoh

Hello Itoh-san,

The gauge devices are similar. We have not updated the bq78z100 TRM yet. However, the recommendation for all gauge devices is no more than 2 I2C standard command transactions per second. In reality, you can send a lot more, but our recommendation is no more than 2 on the TRM.

Hello Kang-san,

The TRM describes that the host must not issue "all" standard commands more than two times per second. I'm a little confused about this sentence.

Is it OK to issue "all" commands on the table 15-1 two times per second? Or, only issuing two commands from table 15-1 per second is recommended?

Best regards,

Itoh