BQ40Z50-R1: SMB returned bytes by BQ

Sebastian Manz

Part Number: BQ40Z50-R1
Other Parts Discussed in Thread: BQ40Z50, BQSTUDIO

Hello,

when I send a SBS command via smbus to the bq40z50, I receive some bytes besides the data I wanted to read, which I have no info about. I'm using Battery Management Studio "Read Block" = 0x51 (Safety Status) and Battery Management Studio shows the answer (block) 0x 00 00 00 00. However an I2C bus analyzer shows the answer 0x 02 00 00 00 00 D8 or something like this. So it seems that the last byte is some kind of checksum and byte 1 to 4 is the data but I don't know what to make of the first byte. Could you please explain the purpose of this byte or point me to the associated documentation?

Thanks,

Sebastian

over 8 years ago

0 Haidar Hamoo over 8 years ago

TI__Expert 4065 points

Hi Sebastian,
Please refer to the TRM of bq40Z50, attached below, section 12.7.37 ManufacturerAccess() 0x0051 SafetyStatus, for more details.
www.ti.com/.../sluua43a.pdf
Regards,
Haidar

0 Damian Lewis over 8 years ago

TI__Mastermind 34775 points

Hi Sebastian,

bqStudio read block is configure to read back max 32 bytes. The first two bytes are the memory address read followed by 32 bytes of data.

Please refer to bq40z50 Data Memory Programming for Mass Production for examples. If you are going to use a micro later to communicate here's a document on SMBus protocols in including read block.

7571.smbus1p10_spec.pdf

0 Sebastian Manz over 8 years ago in reply to Damian Lewis

Intellectual 470 points

Thanks for your response. I'm going to have a look at the SMBus Spec.

Power management

Power management forum

BQ40Z50-R1: SMB returned bytes by BQ