Detective work on PiFace Control and Display

Having wasted all my free time yesterday on trying to find out how the PiFace CAD is interfaced to the Raspberry Pi, I thought I’d take a different approach today. When I was last working with SPI, I used my trusty Saleae Logic analyser to find out what was happening, so I thought I’d connect …

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Driving a LED array from a BeagleBone Black

Over a month ago, now, I had a brief play with my Beaglebone Black. It took me a while but I just about got to the point of flashing an LED. That was enough at the time, but now I want to do something more interesting. So I thought I’d start by doing some patterns …

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txtzyme on Raspberry Pi

After my previous post on delimiter-free languages it occurred to me that the idea of txtzyme has merit for communication between some of the devices I have to hand. Some while ago I spent some time producing some bare-metal code examples for the Raspberry Pi (flashing morse code, GPIO control and uart stuff, for example), …

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Not just Raspberry Pi – playing with an Arduino

I have had an Arduino board sitting in one of my electronics boxes for months. While chatting with an ex colleague yesterday evening, it occurred to me that I had never actually done anything with it. Although it may seem that Arduino and Raspberry Pi are in some sense competitors, I’m seeing more and more …

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Controlling a Slice of Pi/O with Python

I recently got a comment on my article from 1st February about Soldering a Slice of Pi/O asking for some help in programming it in Python. This reminded me that I have not got very far with this little board beyond checking that the Raspberry Pi could see it. So I decided to see what …

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A few new goodies

It seems like ages ago that I was complaining about not being able to access the UART pins when an add on board is attached to the GPIO header of my Raspberry Pi. I even drew a picture of what I was looking for. I still haven’t found anything exactly like that, but I have …

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Testing memory-mapped IO

Following on from yesterday’s post about developing code which uses the memory-mapped IO on the Raspberry Pi, but on a separate development system which does not have the same hardware, I began to think about the steps needed for testing such code. The first stage is unit-level testing. As much of the code as possible …

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Developing memory-mapped IO

I’m trying to make a concerted push on a first working version of CORNELIUS at the moment, and it’s throwing up all sorts of interesting aspects of software development. For the first version I am building the minimum OS and language in C. However, I am trying very hard to minimise the amount of C …

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Hardware abstraction layers

I feel as though I have been spending most of my CORNELIUS efforts on the ELIUS (language) part, and neglecting the CORN (operating system) part. Recently, though, I have been thinking about the notion of a “hardware abstraction layer” (HAL). This is a common part of many systems, and serves to isolate the messy, hardware-specific …

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Controlling Raspberry Pi GPIO from Ruby

After my grumpiness yesterday, I thought I’d better strike out in a different direction while I consider my options with the various sub-projects I have on the go at the moment. I have mentioned before that I am a member of local Ruby user group “IPRUG”. This is on my mind at the moment as …

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