8-digit 7-segment LED display

This is the 8-digit 7-segment display board for the I/O bus (see the specs for the reZet80 I/O bus).

The board displays 8 hexadecimal numbers and 3 additional characters (H, L and blank) plus 8 decimal points.

It uses only one I/O port in the 8-bit I/O space, the display digits are addressed via 16-bit I/O.

Bill of materials:
- PCB 12x8 cm (at least 40 rows)
- 40-pin right-angled male connector
- 4x 2-digit common cathode LED display (common anode also possible)
- DIP-16 socket
- 8x DIP-20 socket
- 74x138 demultiplexer
- 8x 74x374 8-bit flip-flop (or 74x574)
- 64x resistor (choose according to LED specs)
- capacitor 100 nF