Hi nico. We reviewed USB Type C about 2 years ago for a few months and back then there was a lot of chaos as we reviewed many non-compliant cables for power delivery. Reported a lot of our findings to silicon vendors and believe that the issues we observed have been fixed. Do not believe you are concerned about power delivery but more on signal integrity of this reversible connector.
This is a quick summary as there is a lot of good info on the net.
The XMOS IP is USB 2.0 based so you should prepare to support upto USB 2.0 HS (480 Mbps). Be sure to include support for ESD protection and in-rush current on the VBUS rail. This is required for all USB designs and numerous developers have reported damage to their XMOS devices without such protection.
On the USB Type C connector, there are 2 sets of mating pins - one layer on the type side of a blade and another copy on the bottom side. You can safely ignore the USB SS pins (Superspeed signal lines since you are not working with SS = USB 3.0 / USB 3.1 Gen 1 interface).
The signals marked in RED are of interest to your project.
Most articles on the net are just shorting D+ (top) to D+ (bottom) and respectively D- (top) to D- (bottom) and then feeding this single pair of signal lines to their downstream USB device with impedance controlled traces of 90 ohms. This solution may be sufficient for your project but will require thorough testing of the final design.
Microchip is noting that this does impact the signal integrity of the USB 2.0 signals. Reference:
http://ww1.microchip.com/downloads/en/A ... 01914B.pdf
We believe that a more elegant solution to improve the above interface is to insert a USB 2.0 signal mux. This mux will accept in signals from the top and bottom sides of the blade and then switch the mux based on the orientation of the USB connector. See Figure 4 in the above document. The detection of the connector orientation can get complex but believe that there are now single chip solutions for this purpose. Diodes Inc. mentions one but no datasheet - perhaps will release with a request to your local FAE.
https://www.diodes.com/products/connect ... 5USB30216A
* using this component + USB 2.0 signal mux = guaranteed solution but at an added expense
Recently, Cypress (who also has been working on assorted USB Type C solutions - early versions were not to spec when we did our initial review - assuming they have fixed the raised issues by now), check out their PSOC6 kit schematics which makes use of this same connector:
http://www.cypress.com/documentation/de ... ioneer-kit
Taken from their schematics:
They have also just shorted the USB 2.0 signals for their use and without an external mux. We recommend that C85 be 250+ volts. See Johanson caps @ 500v from Mouser:
https://www.mouser.com/Search/Refine.as ... +capacitor
Summary: Most of the industry is just shorting the top & bottom USB 2.0 signals and using in their design. This may be fine for the high speed signals on the XMOS IP but do pay attention to the USB 2.0 impedance controlled traces @ 90 ohms (be sure to inform your PCB shop of where these traces are on your design). Request for your PCB shop to verify these PCB traces are compliant by supplying a TDR test documentation. 4L PCB design is high recommended. ESD protection + in-rush protection is mandatory. Consider the low cost AP2331 for the in-rush protection on the VBUS rail.
https://www.diodes.com/assets/Datasheets/AP2331.pdf
* do confirm if the hold current is ample for your project - Diodes Inc. also offers higher current versions of this component
update
Also a few words on the USB Type C connector. To get started, consider to use a reliable brand through Digikey / Mouser. You can review offshore brands later once your widget is a hit. We are speaking from some experience on offshore sourcing where we met with a manufacturer of USB mini connectors and after ordering their MOQ of 2 T&R, the parts were found to be quite loose in our opinion. We did not want to use for our production. After some chatter between our companies, the CEO of this supplier requested the spec for the mating tension which we hijacked off a datasheet from Digikey. They rebuilt the parts and shipped to us in Canada at their expense. The next batch was ideal but we lost faith in the vendor. The savings were minimal after this exercise with this specific vendor. Recently sourced additional parts from a different source and they have been great for a medical product we recently sampled. Even though it may be expensive, start with local suppliers and consider to receive samples from offshore vendors before assuming that all connectors are created equal.
Be sure to check on the footprints and other physical details to be sure that you are not stuck with a single vendor or manufacturer for the connectors.
Here are the contact details of a vendor we have used in a few projects with excellent results:
http://www.homyet.com/en/products/cid_214.html
Seven Zhang /+86 15112386375
SHEN ZHEN HOMYET PARTS ELECTRONICS CO.,LTD
Tel:+86-755-83676824 29768399
Fax:+86-755-83676835 27888655
Add:306,E Building ,HuaChuangDa Industrial Park,Bao'an 42 District,Shenzhen , Guangdong Province,CHINA
Mail:
seven@homyet.com
Web:
www.homyet.com http://www.homyetparts.com
QQ: 2355400604 Skype:
sevenzhang07@hotmail.com
HONG KONG HOMYET PARTS ELECTRONICS CO.,LTD
Add:Unit 04, 7/F,Bright Way Tower, No.33 Mong Kok Rd, Kowloon, Hong Kong
Tel:00852--23892981
Fax:00852--35902333
Kumar