ADF EXPRESS DEV-BOARD
German Tutorial: https://www.arduino-hausautomation.de/2014/pro-mini-klone-bootloader-flashen/
English Tutorial: https://electronics.stackexchange.com/questions/96805/how-to-program-arduino-nano-pro-mini-pro-micro-clone-that-has-no-usb-port
and you need the Firmware that can be found here http://amiga.robsmithdev.co.uk/instructions
After all you can add your FTDI UART to USB and use the Software.
Watch out that you need at least 7,5V DC to run the PCB, if you run more Voltage like 12V the 7805 regulator is getting hot, do not forget to add a Heatsink.
Normally ypu don’t need 12V for the most Floppy Drives, 5V+ are mostly used.