Hi,
I'm using a BQ78350-R1 which is controlled by a MCU via SMBus. I found out some strange behaviour when I attempt to turn on CHG and DSG FETs with the Hostfetcontrol command.
I hope someone can help me with this problem or have seen similar behaviour:
1. bq78350-R1 FETs CHG and DSG are activated, device in „Discharge state“
2. bq78350-R1 detects Error Overtemp Discharge (simulated error start)
3. MCU reads Errorflag OTD=1 from bq78350-R1
4. MCU reads HCFET=0 from bq78350-R1
5. MCU reads XCHG=0 XDSG=1 from bq78350-R1
6. MCU sends HostFETControl to bq78350-R1: (0x2B, 0x97, 0x11), 5ms Delay, (0x2B, 0x01, 0x00), 5ms Delay
7. MCU reads HCFET=1 from bq78350-R1
8. bq78350-R1 detects Error Overtemp Discharge gone (simulated error end)
9. MCU reads OTD=0 from bq78350-R1
10. MCU switches from its internal „Error state“ to "Discharge state“
11. MCU reads FET_EN=1 from bq78350-R1
12. MCU reads HCFET=1 from bq78350-R1
13. MCU reads XCHG=0 XDSG=0 from bq78350-R1
14. MCU wants to turn on FETs CHG and DSG. MCU sends HostFETControl to bq78350-R1: (0x2B, 0x97, 0x11), 5ms Delay, (0x2B, 0x03, 0x00), 5ms Delay
15. MCU reads HCFET=1 from bq78350-R1
16. MCU reads XCHG=0 XDSG=0 from bq78350-R1 17. FETs CHG and DSG are not active
In some rare cases (about 1 out of 15) the following expected happens:
15. MCU reads HCFET=0 from bq78350-R1
16. MCU reads XCHG=0 XDSG=0 from bq78350-R1 17. FETs CHG and DSG are active
I'am also attached a screenshot of the SMB communication during this process.
So you can see I have no problem with "enable" the Hostfetcontrol, my problem occurs when I try to "disable" the Hostfetcontrol.
Many thanks in advance,
BR, Pat
