We are developing a wireless charger with additional wireless-to-USB gateway functionality.
We have a design where we use the STWB2-HP as a wireless power transmitter - works fine most of the time.
In parallel, we implemented an ESP32-S3 with BT and WiFi.
We use a USB2 compatible USB-C connector.
USB power is used for the whole system.
CC lines are connected to the STWBC2-HP.
Data lines are connected to the ESP32.
On Windows and Linux machines, the data connection works as expected. The STWBC Studio interface reports USB-BC and USB-PD power modes at 5V, depending on the connected host devices.
With a PD wall adapter, all power modes (PD: 5V, 9V, 20V) are available and charging works.
However, when we connect our hardware to a MacOS machine (Macbook Pro M1 2021 or Mac mini), the device is visible for about 1 second and then disappears. The power to the USB port stays on and charging works as expected. Only the data lines are disabled on the USB host (manually resetting the ESP has no effect on the USB connection - unlike non-Apple machines)
We narrowed it down to the CC pin handling between STWBC and the Mac. After the ESP is detected, it is listed in the list of USB devices for about 1 second. The "console" log shows the handling of various CC states and ends with the USB port being disabled. There is no obvious message about excessive power consumption or other errors.
With a USB hub between the charging station and the Mac, everything works. Also, connecting directly to the ESP (STWBC bypassed and 5k1 resistors on both CC lines) works fine.
Anyone got any ideas?
I would be grateful for help. Thanks.
