Budgetronics Z80 retro computer

Z80 Retrocomputer building kit (Budgetronics.eu)

A build of Grant Searle’s famous simple Z80 design


Parts are as expected from Grant’s design, except the EPROM, which is a 27C04012JC. in a PLCC case. A bit overkill (512Mb for a 8K ROM!) but cheap I suspect.
The ROM contents are the Nascom Basic adapted by Grant for a serial terminal. A typical Microsoft Basic of the early microcomputer days.

Connect a serial terminal, e.g. an USB TTL Serial cable to the PCB, start Tera term (Windows) or Minicom (linux), set the serial port to the COM/xTTYUSBxx port, speed 57600, no hardware handshake (or to hardware control connect if CTS to RTS connection  available). If no hardware handshake, then you will have to adapt the delays after receiving character (1ms) and line (20ms) to prevent overruns on uploading Basic program text file. For me this worked out in Tera Term as shown in the next screenshot:

Without any storage facilities this computer is really only usable with a PC as terminal emulator to send files, as if the charaters in the file were typed in.
The same for saving, grab the ASCII output (the log facility in Tera Term for example).

Nice compact design, works perfect within its limitations.