Testing a Z80 MBC-2

Last week I bought a new Z80 homebrew computer from Ebay. Its a Z80 based single board computer with 128KB RAM with some optional modules such as a RTC, GPIO expander and SD disk emulator and runs BASIC and CP/M.

Normally I buy these as kits which you solder together yourself. This one came already assembled with FTDI cable and a preinstalled SD Card.

It arrived via signed-for Royal Mail delivery in a small plain brown box. The components inside were sealed in ESD bags and there was a sheet of paper with some brief useful information. I took the computer PCB and carefully attached the SD card and RTC modules. You have to insert the SD card and a CR2032 battery for the RTC. Finally connect the FTDI cable being careful to orient the cable properly to prevent damage.

Once connected to a USB port on a PC, the device shows in device manager as a Silicon Labs CP21-x USB to UART Bridge (COM7)

Use a terminal emulator like Putty. Connect on a COM port (7) and select the baud rate 115200, click open



Dragon 32 Computer (1983 £159.99 or £575.25 in todays money!)


The Dragon 32 and Dragon 64 were home computers produced in the 1980’s. The 32 had 32KB of memory and so on. They were similar to the TRS-80 Color Computer, and were made by Dragon Data Ltd in Wales.

The Dragon had a 8 bit Motorola MC6809E processor running at 0.89 MHz and had . limited 16-bit capabilities. The Dragon comes with a Microsoft BASIC interpreter in 16 KB of ROM and you could also purchase typical peripherals such as a tape cassette player, joystick etc. They also have quite a nice mechanical switch based keyboard that doesn’t have a membrane.

Today, if you look around the Internet you can purchase modern SD card based drives for loading software and it is possible to upgrade the Dragon 32 to 64KB of memory.

A couple of years ago I bought a Dragon 32 for about £30 on Ebay. The box was rough and the seller said he knew nothing about it and wasn’t sure it worked at all. It came with a book, some games and a joystick and so I decided to take a punt and bought it. Haven’t really done anything with it since so decided to give it a try today.

Powered it on and was happy to see a Basic screen and flashing prompt. Inserted a games cartridge and this worked also with sound. Inside the box is the original receipt and credit card slip for the console. I had forgotten when we all used to manually swipe a credit card on carbonised paper!

Started to try to load some tape cassette games. Here’s where I ran in problems. I tried an old computer cassette recorder and some games partially loaded but none were successful. I then tried a brand new Bush tape recorder and same problems. I only tried about 5 out of 30 or so games but the result was the same. I then downloaded some cas cassette image files from the Internet as wave files onto my Laptop and connected this to the Dragon using the same cassette cable that came with the console. The first couple failed again but after trying “Mission Moonbase”, success!.

Next job, order some capacitors for the PSU and motherboard and look for a good SD card adapter to fill with software.

Weatherspoon’s Don’t Like Veggies

We went shopping today in Watford as we wanted to pop into a Lego store. Decided to have breakfast at Weatherspoons, The Moon Under The Water.

Sat down, placed out online order for a large veggie breakfast and a normal breakfast. The pub was quiet at this time of the morning. The food didn’t take long to arrive.

I started eating my sausage and thought it didn’t taste like their usual veggie sausages and then noticed some bacon tucked under my hash brown. They had given me a meat breakfast.

The staff briefly apologized and offered me a free drink and replaced the breakfast but not happy as such a fundamental mistake. No reason was given for the mix-up so we ate quickly and left.