bq27421-G1 setting of BlockDataCheckSum()

K. Sasaki14

Can we update several Data memory parameters at same time if they are in same BlockData()?
In this case, should we calculate checksum value all together?

For example, when we change Design Capacity and Design Energy,
Does the equation of new checksum become as the following?
temp = mod(255 - OLD_Csum - OLD_DesCap_MSB - OLD_DesCap_LSB - OLD_DesEne_MSB - OLD_DesEne_LSB, 256)
NEW_Csum = 255 - mod(temp + NEW_DesCap_MSB + NEW_DesCap_LSB + NEW_DesEne_MSB + NEW_DesEne_LSB, 256)

Best Regards,
Kohei Sasaki

over 8 years ago

0 K. Sasaki14 over 8 years ago

Guru 10200 points

Hi team,

Could anyone answer for this question?

Best Regards,
Kohei Sasaki

0 Dominik Hartl11 over 8 years ago in reply to K. Sasaki14

TI__Guru 61536 points

Sasaki-san,

Yes, this is possible. The easiest way is to simply read the whole subclass into a data block on your host controller, modify the parameters that you want to modify, calculate the checksum and write the whole subclass back to the gauge.
If you just want to change a few bytes directly in the gauge then you can calculate the check sum like in your example.

Regards,
Dominik.

Power management

Power management forum

bq27421-G1 setting of BlockDataCheckSum()