BQ27421-G1: Please describe how the DM_CODE (control command, sub-addr 0x0004) is derived

Doug Young

Part Number: BQ27421-G1
Other Parts Discussed in Thread: BQSTUDIO

Hi,

I would like to read the DM_CODE from a bq27421-g1 gas gauge IC and compare it to a DM_CODE stored in my application's FLASH memory. If the DM_CODE values match, it will be assumed that the device's data memory parameters match those stored in the application FLASH. Else if the DM_CODE values are not equal, the data memory in the bq27421-g1 would be updated with the parameters stored in FLASH.

1. Is comparing DM_CODE values a valid method of determining if the contents of a device's data memory matches the contents of a golden image for the bq27421-g1?

2. Does the DM_CODE change as data memory parameters such as the RA table are updated over time?

3. How is the DM_CODE created?

Thank you for your help.

Sincerely,

Doug Young

over 8 years ago

0 Dominik Hartl11 over 8 years ago

TI__Guru 61126 points

1. The DM_CODE is just a value stored in data class 64, offset 3. It will not change automatically. You can change it for your specific golden image to a value of your choice and then test it in your program.

2. No. It is a static number.

3. It's 0x00 for the -G1A and 0x10 for the -G1B version. You can change this number in bqStudio to any 8-bit value and this will become part of the golden image.

0 Doug Young over 8 years ago in reply to Dominik Hartl11

Intellectual 315 points

Thank you Dominik, you did a great job answering my questions!

Is there any chance this information could make its way to the next release of the technical reference manual?

0 Dominik Hartl11 over 8 years ago in reply to Doug Young

TI__Guru 61126 points

Doug,

I'll let the team know.

Regards,
Dominik.

Power management

Power management forum

BQ27421-G1: Please describe how the DM_CODE (control command, sub-addr 0x0004) is derived