Dear TI experts please, please help!!!
I would like to understand whats going on on the SMB-Bus between master EV2400 (USB-Module) and slave bq78350-R1 on my EVA-Board bq76930EVM.
(bq78350-R1 talks to bq76930, which is also on the board via i2c. But this i2c is not connected to EV2400 USB-Module).
The Users guide (SLVU925B) of the EVA-Board bq76930EVM describes how to turn on and off the FETs as a first step to get started:
<<<
Page 26
5.9 Device Control
Features are controlled by commands as described in the bq78350 TRM (SLUUAN7). One of the most
basic for operation as described in the quick start section is the FET enable which is toggled by the
ManufacturerAccess() 0x0022 command. The Manufacturer Access commands may be sent using the
Advanced Comm SMB view and the Write Word button...
>>>
I tried this and it worked well! Teriffic!
I have a LED+resistor connected to Pack+/- as load and the LED went on and off via this command.
But I have to understand whats going on on the bus in order to develop my application.
When sending the described command 0x00 0x0022 to 0x17 (Button "Write Word" in "Advanced comm SMB" of bqStudio) I measured the following:
Start 0x16 ACK 0x00 ACK 0x11 ACK 0x00 ACK 0x4B NACK STOP
When sending the described command 0x00 0x0022 to 0x16 (Button "Write Word" in "Advanced comm SMB" of bqStudio) I measured the following:
Start 0x16 ACK 0x00 ACK 0x11 ACK 0x00 ACK STOP
Now 2 questions:
1.
Why is there a difference in the observed signals between Adress 0x17 and 0x16?
Does 0x17 make sense at all when writing, it is not even put onto the bus?
2.
How can I understand the measurement, where is this command 0x0022 (ManufacturerAccess() - FETControl)?
Is there any document ehich can be of help here?
Kind regards
Michael