Now its time to talk about the keyboard, I did a little search in all my city's shop waste to find an used piece, and after a long time I found one, it belongued to a POS(Point Of Sale) it is from Itautec model PDV 54 keys and i payed only $5 bucks.
It will be enough for my project as I am thinking to make monitor's program to help in programming the z80.
At the right side you can see the part that will be used to input program z80's memories.The keys 0 .. F (hexadecimal ) input
The keyboard's schematic.
I did some modifications to the printed board to facilitate the key reading, and in the end it is like the schematic above.
