The BusRaider 2 is an add-on card kit for the RC2014 retro computer which adds memory-mapped graphics, connectivity via WiFi, a web user-interface and single-step debugging.

TRS80 and ZX Spectrum Graphics

Many of the popular Z80 computers of the 1970s and 1980s used a region of memory to produce graphics (either character-mapped or bit-mapped). This area varied in size and location and the formatting of the display generated from this memory also varied widely from the simple character mapped area of the TRS80 to the bit-mapped + colour-mapped display of the ZX Spectrum.

The BusRaider uses a Raspberry Pi Zero (or Zero W) to monitor the Z80's memory and display/emulate/simulate graphics which closely match the output of the original retro computer. So, for instance, it is possible to play TRS80 games like Galaxy Invasion and run some ZX Spectrum games too (see below for more details and active development in this area).

Memory-Mapped Graphics for Retro-Games

I really like the fact that the RC2014 retro computer breaks each module of a computer into a separate board and allows you to see the function of the computer as the sum of its parts. However, a limitation of the RC2014 is the lack of bit-mapped graphics as some of the software I'm interested in (retro games, etc) was developed for a specific computer and made use of its memory-mapped graphics. The BusRaider fills this gap and has some other features too such as the ability to emulate peripherals such as keyboards and joysticks. Furthermore, the BusRaider has hardware that can support single-step debugging and it is currently possible to debug programs running in simpler computer architectures such as the TRS80 - again active development is focused on improving this debugging capability.

So if you like retro games and memory mapped graphics then this is the board for you.

WiFi and WebUI - Browser User Interface

With BusRaider you can control all the features of your Z80 system over WiFi with a WebUI. Storing programs on the BusRaider allows starting games and other software with a click in your browser. You can also change the clock speed in real-time and update your system configuration.

BusRaider Features

The board has been designed to be easy to construct using only a regular soldering iron and other common electronics tools. There is a construction video in the resources to take you from start to finish and the result is a very flexible board which can be used in a number of ways:

• Memory mapped display generation
• WiFi dashboard allowing programs to be started on the Z80 from a web page
• Demo mode to allow quick switching between different computer types and software
• Terminal support for computers using a serial terminal
• Keyboard support for TRS80 and ZX Spectrum
• Telnet (over WiFi) support for remote access to computers using a serial terminal
• Clock generation for the Z80 so that the correct processor speed of different retro computers can be emulated

What's Included

This listing is for a complete kit excluding the Raspberry Pi Zero (or Zero W) and SD card socket/breakout-board. I've excluded the Pi Zero because the internet stores I'm aware of in the UK (Pimoroni, Pi Supply, etc) only sell the Pi Zero on a one-per-customer basis so it is difficult to source in any volume. But fortunately it isn't difficult (or expensive - they are less than $10) to pick one up from them yourself. The SD card socket is excluded because it isn't currently supported in software.

Complementary Memory Card

Note also that the 1MB Linear/Paged RAM/ROM board is designed to go with this product and will significantly simplify getting the more advanced features - like single-step debugging - working.

Getting Started

The following resources will help get started with BusRaider: Build Video Using with RC2014 Pro cards video for a 3 card CP/M system * Documentation

There is a lot more detail in my blog posts listed below and further details will be provided as development of the software continues on debugging support in particular.

BusRaider Intro Blog Post BusRaider Spectrum Blog Post

** As a sneak peek at what BusRaider can do for single-step debugging here's a taster video: Single-stepping a Z80 test program

Notes

• RomWBW is a trademark of Wayne Warthen
• RC2014 is a trademark of RFC2795
• Import duties or taxes may be levied by your country if importing this product and you are responsible for such payment
• This is a kit and requires assembly using a soldering iron, solder and suitable tools

Please note that this is a hobby project and no warranties or guarantees of any kind are provided and no liabilities will be accepted under any circumstances.