Recently I started putting together a Z80 based system from the Retrobrew Computers web site. The build is fairly well advanced, but I’m still waiting on some parts to finish it off.

The Z80 Backplane is mostly done – I went with the 8-slot backplane because 3 was too small, 4 was borderline, and 12 was too big. I figured with an 8-slot board I could start by populating 5 connectors and add the others if I need to.


I still need to get the PCB mount Molex power connector, but otherwise this board is pretty much done. 480 solder joints in the backplane connectors alone!

The unpopulated jumpers between the connectors are, I believe, for enabling DMA & interrupt support – I still need to look further into what’s required here.

The CPU card is this Z80 CPU card – I went with the latest revision board with the two PLCC32 flash memory sockets. Last I checked this revision was marked as “still being tested, but should be OK”, so fingers crossed 🙂


The basic specs of the CPU board are:

  • 4Mhz+ Zilog Z80 CPU.
  • 512Kb paged SRAM.
  • 1Mb Flash ROM.
  • Serial Interface.
  • IDE interface.
  • Real Time Clock.
  • Onboard sound.
  • Battery backup for RTC and SRAM via super capacitor.
  • Standard ECB bus interface.
  • +5V power connector for Single Board Computer operation.
  • Reset button.
  • Recovery mode button.
  • Status LED.
  • Switchable clock speed.

The CPU card has an IDE connector on it, but no floppy drive support, so I’m also building an ECB bus disk controller – this one is based around an 9266 FDC, which is getting a bit hard to find (so I bought two).

This board supports an IDE interface as well, plus a floppy interface, including a 50-pin Shugart variant (for 8 inch drive support apparently).