Other Parts Discussed in Thread: EV2400
Tool/software:
Hello,
I'm a university student working on my final engineering project using the BQ35100 fuel gauge with a custom PCB design. Due to budget constraints, I don't have access to the BQ35100 EVM or the EV2400 interface board.
Current Situation:
- I have successfully implemented I2C communication with the BQ35100 from my STM32 microcontroller
- The device is currently in ACCUMULATOR mode (Operation Config A = 0x80, GMSEL[1:0] = 00)
- I need to switch it to END-OF-SERVICE (EOS) mode (GMSEL[1:0] = 10)
What I've Tried:
- Successfully write to data flash address 0x41B1 (Operation Config A) to change value from 0x80 to 0x82
- Verified the write using checksum and length registers (MACDataSum/MACDataLen)
- Sent the RESET control command (0x0041) after writing
- Reading back immediately shows the old value (0x80)
- After a full power cycle (disconnecting power), the device still reads 0x80
Questions:
- Does the BQ35100 require a specific sequence beyond data flash write + reset to apply new configuration?
- Is it possible to change the gauging mode without BQ Studio or the evaluation module?
- Do I need to unseal the device first before writing to Operation Config A?
- Is there a hardware pin or sequence needed to force the device to reload from data flash?
- Are there any one-time-programmable (OTP) bits that might prevent configuration changes?
My Hardware Setup:
- Custom PCB with BQ35100
- STM32 microcontroller for I2C communication
- Li-SOCl2 primary battery
- GE pin is controlled and set HIGH before communication
Thank you.
