Niklaus Wirth did the same, but his excuse was that he couldn't find a commercial box that would talk to his favourite (Xerox PARC souvenir) mouse.
Some people might have wimped out and just cobbled up a USB translator, but Wirth knew how to take care of things properly: he got an FPGA board, made a soft CPU, and then put all the stuff on top (his OS, his windowing system, his language toolchain, etc.) that would enable him to run his h/w design app and text editor, thereby allowing him to play with more soft CPU-designs ... but this time while using his favourite mouse.
that's hilarious and inspirational. i can barely imagine the work it took just to get a reliable system with basic UART i/o. i can't imagine how much additional work it took before the system was sophisticated enough to even justify a mouse as a peripheral.
Some people might have wimped out and just cobbled up a USB translator, but Wirth knew how to take care of things properly: he got an FPGA board, made a soft CPU, and then put all the stuff on top (his OS, his windowing system, his language toolchain, etc.) that would enable him to run his h/w design app and text editor, thereby allowing him to play with more soft CPU-designs ... but this time while using his favourite mouse.