Other Parts Discussed in Thread: TPS65987D, BQ25703, BQSTUDIO
Team,
I have a customer from the prior post designing with TPS65987D and BQ25703. They have based a large part of our design on the reference design TIDUE65A.
By analyzing the flash bin file and reading the registers, they figured out that the mask value (not terribly well described) affects what loads were. In the GUI tool, they discovered that the radio button “Share Settings Across All Devices” under the Device Initialization Chain should be checked. It appears to alter the mask value to 0xFF and that loads everything as it should. They gave us the feedback that aspect of the GUI is very poorly described.
Now they can run their alpha like the TPS and BQ combined demo boards. They can run the alpha off of battery or USB-C, or run the alpha from USB-C and charge the battery as well. So far so good.
Now they are trying to get the OTG (device as a source) feature working, as they need to support plugging in a thumb drive as well. They are struggling to get this functioning correctly. Here is what they are doing with the eval boards:
The eval boards are set up the way they were to get the charging capability running as noted above. They have the BQ eval board connected via I2C1 to the TPS eval board. Vsys on the TPS eval is connected to the Vin on the BQ eval board. Their battery is connected to the battery terminals on the BQ board.
They have connected the 3V3 supply on the BQ eval board to the P3V3 on the TPS eval board, because if they understand it correctly, 3.3V should be available to keep the TPS digital control core alive or it will be constantly starting from a dead battery state. They configured the TPS GUI using the app note SLVAE18.
When they first connect the battery with nothing attached to the USB-C, everything powers up. If they connect a peripheral to the USB-C (usb mouse in this case), it powers up as expected. They can connect and disconnect it multiple times and it behaves properly.
Next, they connect up their charger to the USB-C port, and begin charging their battery. However, once they disconnect their charger and reconnect the mouse, the mouse no longer powers up. The charger works anytime they connect it, but the USB peripheral no longer works when ever they connect it. One other thing they noticed is that on the TPS eval board, the GPIO14 does turn on, indicating that PDO_0 has been negotiated (that is what it is configured to do in the GUI) but they do not see any traffic on the I2C to the BQ board. I believe that they should see something based on the GUI App configuration data table. However, I do notice that the GPIO PDO event choices list are index 0 (PDO_0, PDO_1..) where as the App Config Data Table PDO negotiation choices are indexed 1.
Any thoughts?
