I am having a problem with a batch coming off from production. We have (and have been using) BQ27500-V120 parts that we then program with v1.30 before loading our *.dfi image.
Before starting we can go to the DataRAM or Data Flash screens and refresh settings and do not see anything that stands out. Our voltages appear correct and we appear to be able to communicate fine to the board.
We use the bqEasy software (v0.9.59) via the EV2300 to do this:
1. Write data block (I2C Command:00 DataBlock:000F) in the I2C screen to enter ROM mode
2. Select the bq27500_1_30.senc in the bq275xx Programming section and click on "Program"
Normally this works, but we are receiving error "Target not in ROM mode!" After this, we also cannot refresh the DataRAM menu without power-cycling the chip. I have tried unlocking the bq27500 prior to flashing with no success.
We have validated our test stand is okay by using a previously tested board and unlocking it, and have been able to flash it without issues.
So my questions are, what conditions must be set in order to enter ROM mode? How do the error messages "Target not in ROM mode!" differ from the error code we usually see when the 000f write is forgotten (Comm error code = 772)? What else should I be looking at as a potential fail point? What other information may I provide that can assist with any answers?
Working bq27500 chip markings: bq 2750 TI K 054P
current batch of bq27500's: bq 2750 TI K 181R
Thank you,
Marc