All the contemporary CPUs you find on affordable boards have only 3.3V (maybe some even 1.8V, at least on a subset of pounds) I/O. Not directly connect able to

All the contemporary CPUs you find on affordable boards have only 3.3V (maybe some even 1.8V, at least on a subset of pounds) I/O. Not directly connect able to chips as used in the Alto. There are still a few CPLD/FPGA available with 5V capable banks, which would be preferable, so you'd build a JTAG TAP for single ICs. At this point, you could as well connect it to a PC using a JTAG pod .