BQ32000: Issue with BQ32000 RTC Communication Using MSPM0L2228 (Bit-Banged I2C at 4 MHz)

Part Number: BQ32000
Other Parts Discussed in Thread: MSPM0L2228

Dear Support Team,

I am currently interfacing the BQ32000 RTC with the MSPM0L2228 microcontroller.

System details:

• MCU: MSPM0L2228

• MCU Clock Frequency: 4 MHz

• Communication Method: Software (bit-banged) I2C

• RTC Device: BQ32000

The I2C communication is working correctly during initialization and for some time afterward. However, after running for a while, the RTC starts returning garbage values (invalid time/date data). Then, without resetting the system, it again starts returning proper RTC values.

This behavior repeats intermittently.

Additional observations:

• No hardware reset is applied to the RTC during the issue.

• Pull-up resistors are properly connected on SDA and SCL.

• The issue appears randomly after stable communication.

Could you please help me understand:

1. Possible causes for intermittent garbage data from BQ32000?

2. Whether 4 MHz MCU clock may affect software I2C timing stability?

3. If there are specific timing requirements or bus recovery recommendations for this device?

4. Any known issues when using bit-banged I2C with BQ32000?

Please let me know if you need scope captures, I2C waveforms, or register dumps for further analysis.

Looking forward to your guidance.

Surya.