Hello,
We are currently experiencing an issue in which the BQ25155 does not properly respond to a request for I2C register 0x6F. Normally, the device responds with 0x35. However, when VIN is applied for a brief moment to bring the device out of ship mode, then quickly removed, we notice the device responds with the value of 0x19 at reg 0x6F. The 0x19 response is confirmed with external scope sniffer decode as well.
This issue seems very similar to BQ25155: I2C reading operation problem
This issue is deterministic and can be replicated with the following steps:
- Put the BQ25155 in to shipmode
- Apply 5V to VIN for a brief moment to bring the device out of shipmode
- Wait for a short time (20 secs)
- Apply 1.8V to VIO
- Apply pull up to VIO on SCL and SCA
- Wait 100ms
- Apply pull up to VIO on /LP
- Wait 2ms
- Request reg 0x6F
- Read 0x19
When VIN is steadily applied and never removed in step #2 above, then 0x35 is read from reg 0x6F in step #10.
We have duplicated this issue across several duplicate devices. We have not yet reduced the issue to a minimum necessary circuit yet, but I am sure we will get there eventually.
I just wanted to reach out and see if there were any thoughts on why we might be seeing this or published part errata that we could download.
Thank you,
James
