We’ve touched on this area before with the software layout and planning post but a lot has happened since then. This includes a GitHub repository where the latest version of our code can be found here. If you fancy having a read through it and reckon you have spotted any problems or know a better way of doing things then let us know and we’ll look into what you’ve spotted.
Work in progress system class diagram
For the most part it is structured just like the diagram suggests we had it planned. A cool feature of the project is that the code is portable to other platforms, with just a simple rewrite of the lowest level classes – I2C and Quick2Wire. This means that you could implement the TwitALU on completely different hardware – for instance on the BeagleBone Black or even an ARM based mobile phone.
- Twitalu v0.1 PCBs
After a very exciting unboxing of the first ever PCBs that Jeremy and I have ever ordered, I started the task of constructing and populating the boards.
The first task was to break the tabs that we had created to avoid PCBTrain’s pricing. This proved to be really easy with a guillotine. The edges of each board were then sanded down on a belt sander to smooth out the tabs. Continue reading
That’s right everyone, after a few weeks of tense waiting and software writing the first version of the PCBs have finally arrived so let’s have a peek inside the box.
“I’m so excited, and I just can’t hide it…”
Here we go everyone, as promised, a video of the prototype system working from start to finish! I can recommend viewing it in HD at full screen with a bit of volume for effect. Obviously theres still the final system to create but this is the big turning point in functionality. Let us know what you think in the comments here or on YouTube we’re interested to know what you think of the system as much as the video at this stage.
That’s right It’s finally happened everyone, at 3:31pm on the 23rd July 2013 the following exchange took place on Twitter between myself and the TwitALU system!
The first command and response processed by the prototype ALU hardware
Great, we now have a hardware ALU with its most important elements implemented on a metric tonne of breadboard. However, this awesome little machine is missing a crucial component – the interface to Twitter.
Enter the Raspberry Pi (RPi) – everybody’s favourite credit-card sized PC. As good as it is for playing back high-definition video and surfing the web with a connected monitor, its real power is harnessed when it’s used for a different, deeper purpose.
Twitalu v0.1 PCB Front
So here it is guys! Version 0.1 of the Twitalu’s main board. This version implements all the features within a MOS 6502 processor’s ALU. When combined with the registers that Jeremy has built and the software that’s being programmed on the Raspberry Pi, the Twitalu will take its first baby steps by adding two numbers together! Check out the rear side after the break.