Question from a dummy in electronics: how do you "flash" this kind of chip (i.e. inject inside, the compiled FPC code)? Is an Arduino required with its "EDI", before this kind of electronic "test" board?
I can't speak for that specific chip, but by and large you need something like Avrdude plus a little interface box that costs about a fiver (some of which need a firmware update before they're useful, links if you're interested).
If the chip has been set up ("fuse bits" which are actually rewritable) to ignore that protocol, there's another that uses a special AVR debug mode.
And if that's disabled there's JTAG.
If you've got the Arduino IDE then by default it assumes that there's a loader at the top of Flash which talks 5V serial to a PC. That doesn't stop you from taking the generated .hex file and getting it into Flash some other way.
MarkMLl