The simplest variant of a backplane

Just a Veroboard in Eurocard format (but any format would do) with 40-pin female sockets soldered to it.

A 100 mm Eurocard accomodates 39 strips (rows).
That's OK for now as the HALT signal is of no interest in the current design stage.

The second stripboard you see is the I/O bus I'm experimenting with, so just forget about it.

16x1 LCD display

This is the LCD 16x1 board for the I/O bus (see the specs for the reZet80 I/O bus).

It is similar to the 20x4 LCD board because all LCD displays provide the same parallel interface:

 1: GND
 2: +5V
 3: V0
 4: RS   [A0]
 5: R/W  [/WR]
 6: E    [IOSEL inverted]
 7: DB0  [D0]
 8: DB1  [D1]
 9: DB2  [D2]
10: DB3  [D3]
11: DB4  [D4]
12: DB5  [D5]
13: DB6  [D6]
14: DB7  [D7]
15: VDD backlight
16: GND backlight

A variable 4k7 resistor connected to V0 is used to set the display contrast. Another resistor is connected between LCD pin 16 and GND if VDD backlight is less than 5V, otherwise connect pin 16 directly to GND.
Please always check your LCD display specs!

Bill of materials:
- PCB 5x7 cm (at least 23 rows)
- 23-pin right-angled male connector
- DIP-14 socket
- DIP-20 socket
- 74x04 hex inverter
- 74x245 octal bidirectional transceiver
- resistor 6.8R (choose according to the LCD specs)
- variable resistor 4k7
- capacitor 100 nF

amber display from my Yamaha FB-01