Early reZet80 history - stage 4

It was time to get serious. The reZet80 DEV was on its way.

Again I soldered all boards from scratch and developed new hardware/functionality.

A separate I/O board with LEDs to keep track of the port being accessed

A 16-key keypad

A real-time clock (RTC)

And two LCD displays (16x1 and 20x4 chars)

I extended the bus to 80 lines.

I used separate ROM and RAM chips for the first time (32 KiB each).

The power supervisor started to cause trouble from time to time so made it optional.
Operation was stable all the time. This was my proof of concept for the hardware design!