Is it possible for the BQ27441 to enter an OTP PROGRAMMING state, similar to the BQ27411? If so, what conditions would cause this state transition to occur?
For our BQ27441 installation, on POR the ITPOR bit is set in the CONFIG_STATUS register, but the values loaded from ROM do not match those in the Technical Reference Manual:
What we actually read:
- Design Capacity: 424
- Design Energy: 1588
- Taper Voltage: 3200
- Taper Rate: 4
It appears that bits have been knocked down from the pre-programmed ROM values, suggesting that ROM is being unintentionally accessed and modified at some point. These values are always the same on subsequent POR.
The BQ27441 data briefly references some OTP capability but this is not mentioned in the Technical Reference Manual or other documentation. The BQ27441 does not appear to have a PROG pin.