Overview
The RC2014 is a modular computer system based on Zilog's Z80 CPU and clocked at 7.3728mhz, with 8k ROM, 32k RAM, Serial I/O and various other add ons under development. Created by Spencer Owen, originally as his entry into the Retro Challenge Summer 2014 competition the project has now developed into a website and blog as well as a set of professionally made PCBs available on Tindie to help make the process of building your own so much less painful.Getting Started
After unpacking the PCBs and gathering together all the other components needed, I started to consider my options of where I should start and what should go together first. It was around that time I spotted a photo of Spencer's RC2014 with a nice neat label on the backplane that details the function of every pin on the system bus, I asked if he could send me the document so I could print my own and although he'd deleted the original file, he very kindly went to the time and effort of recreating it and made it available for everyone download and print their own.
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| The PCBs, sockets, headers and Veroboard. |
Backplane
The backplane seemed like a good place to start as it the basis of what holds everything together in this modular system, before I start building the modules themselves as a set rather than completing each one individually. This means I can start with the resistors and other passives, then the IC sockets, headers and finally the other large components such as the DB-9 connector for the serial port, leaving the ICs 'till the very last step to safeguard them from static discharge. |
| I settled on 7-7-7-10-10-12 hole slot spacing. |
First job was to work out how many slots I should have on my backplane and how much space there should be between each slot, after trying a few different combinations I settled upon a configuration that would allow enough space for the standard modules to be placed side by side and at least two widely spaced slots to make it easy to fiddle around with my own designs. My backplane is based on a Maplin A63RL Veroboard with a 40 track by 61 hole layout (though only 60 holes are usable), which at £6.99 is the only 40 track piece of veroboard I could find without waiting weeks for delivery at an even remotely sensible price, the idea of etching my own backplane board did enter my head and the linear nature of the bus design would mean it would only have to be a single sided board, but that could well turn into a project in it's own right.
I reckoned that 7 slots would give me the best balance of expandability versus physical access, allowing me to configure the machine with the standard modules in place and have enough room to test one or two modules of my own or expose the bus for other experiments, such as connecting an Arduino Mega board to act as an EPROM emulator/supervisor or for trying out new ideas on a breadboard. The 'slots' themselves are readily available 40 pin female SIL headers, making it not only really easy to assemble the backplane, it also means that all the bus signals are all there in one line which minimises the potential for mistakes when prototyping new hardware.
With all that done I switched my iron on to warm up, gritted my teeth and prepared myself for 280 solder joints...
