Here is a very urgent and strange issue for our bq20z75.
Customer using the bq20z75 for a UPS. At first , that all things goes well for almost testing. However, today they found that the gauge reports the Voltage and Temperature very strange which is read by bqEVSW. It seems like that the SMBus engine was not working well . Sometimes reading the voltage all be 0. Here is the log from customer side. We measured the all LDO voltage is stable .
Reset command cannot make it getting well at all. Then we read the senc file out and programmed to another good board. We can see the same strange behavior. I also try to program the senc file to our EVM . The issue also occurred. It is not the hardware problem.
When looking the data flash in detail , we found portion of registers cleared to 0.
- Once the flash erasion issue occurred, does the data always be “0”, or the bit of registers would be either “1” or “0” unsure?
- Is the flash of bq20z45 NAND flash or EEPROM? I try to search about the erased status for NAND Flash, which is all “FF” at default . On this case, what we saw , part of data flash was setting back to “0”.
- For the SDA and SCL line of SMBus, are they connected to the Flash directly internal? That would give the path to the Flash memory by ESD/EMI to cause the erasion issue?