Host is PC and slave is Renesas RX111
We have a working solution (Rx111 board to PC over USB), without isolator.
We have evaluated by adding an ADUM3160 module in between and it works fine. The module I used is USB Isolator Module ADUM3160 USB Digital Isolation USB to USB Voltage – 52Pi Store
Now we have designed the board by adding ADUM4160, since we needed higher isolation and single board solution, assuming 3160 and 4160 have identical pinouts. But somehow communications are not happening.
We have 2 USB firmwares to test communication, one is our custom implementation, and the other is USB Boot loader provided by Renesas, Both do not work. We have added an additional opto isolator to have USB_VBUS to the microcontroller to change state when the USB is connected.
Based on observations of both the D+ and D- lines of both the designs, we see D+ and D- lines are complementary in the working design, but with the ADUM4160 design D- looks to be stuck at zero. This has been observed in 3 prototype boards, so it is not a single board issue.
