Recently a, Ultra96-V2 user on the 96boards support forums asked the question "I was wondering if it was possible to connect to the UART directly via jumper leads? Anyone do this?"
This is a good question, and it got me thinking. If you don't need the JTAG interface, and thus aren't using the Avnet USB UART/JTAG AdapterAvnet USB UART/JTAG Adapter, then yes you can still use the UART. You do still need an adapter of some sort, though, because the UART Rx and Tx signals cannot be connected directly to a RS-232RS-232 serial port. A PC’s UART is usually RS-232RS-232, and as such the signaling for the Rx and Tx is often -12V to +12V. The signaling for the Ultra96-V2 UART, on the other hand, is 0V to +3.3V.
You can, however, make your own USB UART adapter fairly easily like this person did on the Element14 forums:
Building a USB UART Serial Adapter
You can also follow this tutorial on Hackster.io:
https://www.hackster.io/LogicTronix/how-to-connect-ultra96-fpga-with-ftdi-uart-arduino-module-9799ba
You will need to purchase a 3.3V TTL UART adapter like these:
Microchip MCP2221A UART ModuleMicrochip MCP2221A UART Module
USB UART Adapter CableUSB UART Adapter Cable
NXP MCU LinkNXP MCU Link
Keep in mind the UART connector on the Ultra96-V2 is 2.0mm spacing so you will need jumper wires that can convert this to the more standard 0.1" spacing:
https://www.amazon.com/gp/product/B0143YRKUQ/
https://www.amazon.com/gp/product/B00M5WLZDW
There is more good information here about UART adapter options for the Ultra96-V2 board:
Ultra96-V2
Buy Ultra96-V2Buy Ultra96-V2
Ultra96-V2 I-grade
Buy Ultra96-V2 I-gradeBuy Ultra96-V2 I-grade
Ultra96-V2 4A Power Supply
Buy Ultra96-V2 4A Power SupplyBuy Ultra96-V2 4A Power Supply
Ultra96-V2 JTAG/UART Adapter
Buy Ultra96-V2 JTAG/UART AdapterBuy Ultra96-V2 JTAG/UART Adapter
96Boards Click Mezzanine Starter Kit
Buy 96Boards Click Mezzanine Starter KitBuy 96Boards Click Mezzanine Starter Kit