I am designing a board around the RBp Compute and would like to add WiFi connectivity to this device. However, I do plan on using USB 2.0 for its datarate (e.g. to send and receive images), so the ESP32 and other modules with UART comm are not viable options. Has anyone made a out of the box wifi module work with the Compute? And if yes, which ones? The Raspberry forums weren't really helpful. Thanks!
The compute module has USB signals on the SODIMM connector.
USB_DM are the differential pair used for communication. You should be able to connect any USB device to these. Keep in mind that you will need to connect
GND line as well, and in case of host-powered devices (the vast majority of WiFi adapters) you'll need to provide 5V to the adapter as well.
Note that USB 2.0 signals have a much higher frequency than e.g. GPIO pins (480 MHz vs. single-digit MHz), so you should make any wires / PCB trances carrying these signals as short as possible (and of equal length within ~5mm tolerance). Ideally, you should use a twisted pair with 90 Ω ± 10% total impedance. In particular, USB 2.0 will not work over stray jumper wires.