Electronic – Custom-CPU builder/simulator

The PS/2 keyboard is very easy to interface, and a PC/XT keyboard (with the 5 pin DIN connector) is even easier. For the PC/XT keyboard you just need a 8-bit serial-to-parallel shift register. The keyboard will automatically clock out a 9-bit key scan code for each key press and release; you can connect the keyboard clock signal to the clock in pin of the shift register and data signal to the data in pin of the shift register and you'll conveniently get a 8-bit key code + 1 interrupt bit for each keypress (the 9th bit will be in the shift register's serial out pin and that one you can also use as an interrupt signal if you also clear the shift register after reading each scan code).

For PS/2 keyboard it's similar but there's a few extra bits. Since you are running on the FPGA, it's probably no problem for you to make a 12-bit shift register instead of a 9-bit shift register.

Quick answer is yes, you should always take into consideration ESD risks.

You should have an ESD protected surface and a ground strap (there is some argument for ESD protection gloves, but you don't see them in use much, at least I haven't seen them used much in industry).

The ground mat (like this one: Maplin anti-static mat) is the most important bit (IMO) as you can us that to give yourself a good grounding to reduce your ESD. But you have to make sure the matt itself is grounded, that is the most important bit, any expense on ESD protection is wasted unless you have a good route to ground.

Many bits of ESD protection (such as the one linked to) have clips to attach to a "good ground", but you can also get plugs (like in this kit: Maplin anti-static kit) which would be my preferred option.

But I would say that re-balling a BGA is a very risky operation anyway, I would be more worried about that than the ESD risk.