(Incomplete, I ran out of Cherry switches !)
A QWERTY keyboard for the MK14E which provides 40 key switches on a 4x10 matrix, uses Cherry MX switches. It maps into the same matrix as the onboard Keypad but is not intended to replace the existing Keypad. The plan is for it to be used with NIBL but this requires a terminal type program to be produced in place of the serial interface. The allocation of characters to keys is flexible, my plan is to do something similar to the ZX80/81 making sure that all the symbols used by NIBL are available.
My prototype is not fully populated because I ran out of switches but it does work.
Schematic
Bill Of Materials
Blank PCB
