DE1 FPGA FTDI conflict with other devices

You don't mention what software tools you're trying to use as part of your 'communication'. However, the Altera tools support multiple 'USB-Blasters' (this includes dev kits such as yours) allowing you to specify which one to use for each application. On the command line you'd typically add a "--cable" option to do so. E.g.

nios2-terminal.exe --cable="USB-Blaster "

The USB-Blaster on the DE1-SoC kit I currently have connected appears as "DE-SoC [USB-1]" - your board may appear as something similar.

Failing that there is a utility that FTDI offer that allows you to reprogram the EEPROM inside an FTDI device. note: this carries risks in that, if not careful, you could render your hardware unreachable.

Read about and download the utility from here: ftdi - ft_prog (http://www.ftdichip.com/support/utilities.htm#ft_prog)

This could allow you to change the identity of one of your FTDI devices such that whatever software you're using doesn't consider it a valid device to use. You may well (almost certainly) have to make a complementary change to whatever software you're using to communicate with this FTDI device with the altered ID. disclaimer - I've not done this part myself but have successfully used the FT_PROG utility to reprogram and use FTDI devices for communications.

Happy New Year,

Alex