I'm investigating developing a board with a USB-C connector, tied to a USB 3.0 hub, which would have various downstream ports connected to an MCU, thumbdrive, etc. My question is about the four pairs of SS TX/RX signals on the connector. I understand the CC pins can be used to determine the connector/cable orientation. So would I need to use switches to select between the TX1/RX1 and TX2/RX2 pairs based on the state of the CC pins, and connect the outputs to the hub? Are there components that incorporate all this (detecting the CC and switching the USB-C signals to provide the SS TX/RX pairs)?
Are the second set of SS pairs used only by USB 3.2 devices?
I'm looking at TUSB8040A from TI currently for the hub, and PI3USB302-A from Diodes for switches. Any thoughts or other suggestions?
Best Answer
USB Type-C connector should be wired in accord with "USB Type-C connector specifications". The latest specifications are a part of "USB 3.2" package release (zip format), which can be found on USB.org website. The document has 240 pages and explains several variants how the Type-C connector should be wired.
To make it clear, it is not that "CC pins can be used", the CC pins MUST BE USED to determine orientation and proper selection of Tx/Rx pairs for multiplexing.
Since this particular hub doesn't support native Type-C interface, additional ICs must be used. To start, look at Texas Instruments portfolio of Type-C support. Several other companies as Rohm, Fairchildsemi, Cypress, STMicroelectronics, VIA, etc. etc. offer ICs to support Type-C finctionality.
You can also look at hubs that support Type-C multiplexing natively, I believe VIA already makes some (look up VL821).