BQ78350-R1: ROM Mode commands and updating FW

Hi Joshua,

Are you needing to program different firmware to the device (for example some customers program BQ78350-R2 firmware if they need features only available in the R2)? This is the only reason you would need to use ROM mode since the address range 0x100000 onward is instruction flash and should not be written unless you need to update the firmware version.

In the past, some users have used ROM mode to update the firmware to the latest version. However, the latest version of the R1 firmware is available pre-loaded on the device if you order the BQ78350-R1A.

There are different commands for ROM mode that are not described in the TRM. I do have some example code I can share with you privately if you send me a friend request on E2E.

Best regards,

Matt

Hi Matt,

We have some units that were undergoing some in-house testing that we accidentally put into "Permanent Fail" mode (due to incorrect current threshold settings).  My understanding is that the only way to "reset" the BMS out of this mode is to re-program the firmware, as data flash writes are disabled once Permanent Fail is triggered.

Is there any documentation regarding the specific changes included in the updated R1A firmware?  How does this differ from the R2 firmware?

Thank you for the quick reply; I have sent you a friend request..

Hi Joshua,

I understand. In this case, you can send the command 0x0029 (Permanent Fail Data Reset) and then you should once again be able to write to data flash.

This thread explains the differences between R1, R1A, and R2 firmware: 

https://e2e.ti.com/support/power-management/f/196/t/879900

The only difference between R1 and R1A is the Shutdown routine is more robust for the R1A. We recommending using the R1A since it is functionally identical to the R1.

Let me know if you still need the code example for writing instruction flash.

Best regards,

Matt

Hi Matt,

So if I understand correctly, sending the 0x0029 (Permanent Fail Data Reset) clears the saved PF data and takes the gauge out of "Permanent Fail" mode, as if the mode was never triggered?

I would still like the example code to use for our internal testing.

I have one last question, about the Permanent Fail data stored in the Data Flash:

For e.g. Safety Alert, which bytes "A,B,C,D" correspond to which bits of the SatefyAlert register?

RSVD (Bits 31–21): Reserved
OC (Bit 20): Overcharge
CTOS (Bit 19): Charge Timeout Suspend
RSVD (Bit 18): Reserved
PTOS (Bit 17): Precharge Timeout Suspend
RSVD (Bits 16–15): Reserved
OCDL (Bit 14): Overcurrent During Discharge Latch
OTF (Bit 13): Overtemperature Fault
AFE_OVRD (Bit 12): AFE Alert
UTD (Bit 11): Undertemperature During Discharge
UTC (Bit 10): Undertemperature During Charge
OTD (Bit 9): Overtemperature During Discharge
OTC (Bit 8): Overtemperature During Charge
ASCDL (Bit 7): Short Circuit During Discharge Latch
ASCD (Bit 6): Short Circuit During Discharge
AOLDL (Bit 5): Overload During Discharge Latch
AOLD (Bit 4): Overload During Discharge
OCD (Bit 3): Overcurrent During Discharge
OCC (Bit 2): Overcurrent During Charge
COV (Bit 1): Cell Overvoltage
CUV (Bit 0): Cell Undervoltage

i.e. is Permanent Fail Safety Alert A bits 24-31 or bits 0-7?

Thank you,

Joshua