FTDI Community

General Category => Discussion - Hardware => Topic started by: radioman85 on November 29, 2022, 12:22:50 PM

Title: FT231X vs. USB-C - doesn't work!
Post by: radioman85 on November 29, 2022, 12:22:50 PM

Hi there,

I have a HW design using USB-C receptacle and an FT231X behind it to establish a simple serial interface to the PC. Now, using a cable connected to a USB-A port on the PC the PC (using FT-Prog) reconginzes the FTDI chip of my HW. Connecting it to a USB-C port of the PC the PC (i.e. FT-Prog) is unable to find it. For USB-C I have connected a 5k1 resistor between CC1 and GND/CC2 and GND. Else there shouldn't be any difference, is there?

Well, this shouldn't be an issue anyway, as it is only required for certain power negotiation (correct me if I'm wrong).

Now, what could be wrong?

You can find necessary schematics attached.

Thank you in advance for any help!

Title: Re: FT231X vs. USB-C - doesn't work!
Post by: FTDI Community on November 29, 2022, 05:00:18 PM

Hello,

Please see TN_181 Type-C USB Connectors with FTDI Products (https://ftdichip.com/wp-content/uploads/2021/12/TN_181-Type-C-USB-Connectors-with-FTDI-Products.pdf) which should help you.

You are missing 5K1 resistors on the CC1 (A5) and CC2 (B5) lines which are required.

You may have got these mixed up with A8 and B8.

Also there should be 27ohm an 47pF on the USB data lines. I can see 22ohm in your design which is incorrect.
See AN_146 USB Hardware Design Guidelines for FTDI ICs (https://ftdichip.com/wp-content/uploads/2020/08/AN_146_USB_Hardware_Design_Guidelines_for_FTDI_ICs.pdf) for more details.

Best Regards,
FTDI Community

Title: Re: FT231X vs. USB-C - doesn't work!
Post by: radioman85 on December 01, 2022, 02:30:20 PM

Thx for your links. I'll go through them and see if I find something.