USB-C Interface¶

This page provides tips for using the USB-C interface on the MitySOM-A5E Mini or Standard Development Kit as well as the MitySBC-A5E development board.

This project assumes that you have enabled the USB-C interface on the Agilex-5 SOM and have properly configured the linux device tree. The default FPGA and micro-SD card images should provide support for the USB-C interface.

Using the USB-C interface as an ethernet gadget.¶

The USB-C interface supports both upstream and downstream data modes. The following commands can be added to a script to enable the USB-C port as a downstream ethernet gadget. This will allow users to plug the USB-C port to a HOST PC running Windows or linux using a standard Type-C to Type-C or Type-A (USB 3) to Type-C cable and have an ethernet interface to the Agilex 5 HPS target.

# Set up NCM gadget
modprobe usb_f_ncm
cd /sys/kernel/config/usb_gadget
mkdir g1
cd g1
echo 0x1d6b > idVendor # Linux Foundation
echo 0x104 > idProduct # Ethernet Gagdet
mkdir configs/c.1
mkdir functions/ncm.usb0
ln -s functions/ncm.usb0/ configs/c.1/
echo 11000000.usb1 > UDC

This sets up a usb0 network interface; it won't get an IP address until you plug it into the PC, at which point the SOM statically sets its IP address to 10.1.47.2/24 and then acts as a DHCP server to assign the PC the address 10.1.47.1/24.

This is particularly useful with the MitySOM-A5E Standard Devkit, as the standard RJ-45 ethernet jack is not supported with Engineering Silicon devices due to device errata dealing with the HSIO LVDS serializer capabilities.

This provides an easy way to update files on a booted HPS filesystem microSD card that does not involve removing the microSD card and inserting it into a Host PC microSD slot card reader.