A RISC-V Operating System Instruction Manual

To some, an operating system is a burden or waste of resources, like those working on embedded systems and other low-power applications. To others it’s necessary, abstracting away hardware so that higher-level programming can be done. For most people it’s perhaps not thought of at all. But for a few, the operating system is the most interesting piece of software running on a computer and if you’d like to investigate what makes this often overlooked aspect of computer science interesting, take a look at this course on operating systems from Cornell University.

The operating system itself is called Earth and Grass Operating System because it splits the functionality of the operating system into three separate parts. The Earth layer involves dealing with hardware, the Grass layer involves hardware-independent aspects, and a third application layer implements other key operating system features. It’s built for a RISC-V processor, since that instruction set is completely open source and transparent about what it’s doing. It’s also incredibly small, coming in at around 2000 lines of code. The course covers nine areas, with the first six being core operating system functions and the remaining three covering more advanced operating system concepts.

For understanding the intricacies and sometimes mysterious ways that operating systems work, a course like this can go a long way into unraveling those mysteries and developing a deeper understanding of how it brings the hardware to work for higher-level software. We actually featured this operating system two years ago, before this course was created, which covers this project for those who like to take a more self-directed approach, or simply want a lightweight OS for a RISC-V system.

Intercepting And Decoding Bluetooth Low Energy Data For Victron Devices

[ChrisJ7903] has created two Ardiuno programs for reading Victron solar controller telemetry data advertised via BLE. If you’re interested in what it takes to use an ESP32 to sniff Bluetooth Low Energy (BLE) transmissions, this is a master class.

The code is split into two main programs. One program is for the Victron battery monitor and the other is for any Victron solar controller. The software will receive, dissect, decrypt, decode, and report the data periodically broadcast from the devices over BLE.

The BLE data is transmitted in Link-Layer Protocol Data Units (PDUs) which are colloquially called “packets”. In this particular case the BLE functionality for advertising, also known as broadcasting, is used which means the overhead of establishing connections can be avoided thereby saving power.

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Screen shot of Mongoose Wizard.

How To Build An STM32 Web Dashboard Using The Mongoose Wizard

Today from the team at Cesanta Software — the people who gave us the open-source Mongoose Web Server Library and Mongoose OS — we have an article covering how to build an STM32 web dashboard.

The article runs through setting up a development environment; creating the dashboard layout; implementing the dashboard, devices settings, and firmware update pages; building and testing the firmware; attaching UI controls to the hardware; and conclusion.

The web dashboard is all well and good, but in our opinion the killer feature remains the Over-The-Air (OTA) update facility which allows for authenticated wireless firmware updates via the web dashboard. The rest is just gravy. In the video you get to see how to use your development tools to create a firmware file suitable for OTA update.

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Unreleased Amiga Hardware Plays MP3s

The MP3 file type has been around for so long, and is supported by essentially all modern media software and hardware, that it might be surprising to some to learn that it’s actually a proprietary format. Developed in the late 80s and early 90s, it rose to prominence during the Napster/Limewire era of the early 00s and became the de facto standard for digital music, but not all computers in these eras could play this filetype. This includes the Amigas of the early 90s, with one rare exception: this unreleased successor to the A3000 with a DSP chip, which now also has the software to play back these digital tunes.

The AA3000, developed as a prototype by Commodore, was never released to the general public. Unlike the original A3000 this one would have included a digital signal processing chip from AT&T called the DSP3210 which would have greatly enhanced its audio capabilities. A few prototype boards did make it out into the hands of the public, and the retrocomputing scene has used them to develop replicas of these rare machines. [Wrangler] used one to then develop the software needed for the MPEG layer 2 and 3 decoder using this extra hardware, since the original Amiga 3000 was not powerful enough on its own to play these files back.

If you want to follow along with the community still developing for this platform there’s a form post with some more detail for this specific build (although you may need to translate from German). [Wrangler] additionally points out that there are some limitations with this implementation as well, so you likely won’t get Winamp-level performance with this system, but for the Amiga fans out there it’s an excellent expansion of this computer’s capabilities nonetheless.

Thanks to [Andy] for the tip!

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Reverse Engineering LEGO Island

While LEGO themed video games have become something of a staple, in 1997 they were something of an odity. LEGO Island became the first LEGO video game released outside of Japan in 1997 and become something of a hit with over one million copies sold. The game was beloved among fans and set the stage for more LEGO video games to come. In an effort of love, [MattKC] put together a team to reverse engineer the game.

The team set out with the intent to create a near perfect recreation of the codebase, relying on custom made tools to run byte checks on the rewrite compilation and the original binary. While the project is functionally complete, [MattKC] believes it is impossible to get a byte accurate codebase. This is because of what the team called “compiler entropy.” Strange behaviors exists inside of Microsoft’s Visual C++ compiler of the era, and small changes in the code have seemingly random effects to unrelated parts of the binary. To mitigate this issue would likely require either partially reverse engineering Visual C++ or brute forcing the code, both of which would take a large amount of effort and time for no real benefit.

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Now KDE Users Will Get Easy Virtual Machine Management, Too

If you work with virtual machines, perhaps to spin up a clean OS install for testing, historically you have either bitten the bullet and used one of the commercial options, or spent time getting your hands dirty with something open source. Over recent years that has changed, with the arrival of open source graphical applications for effortless VM usage. We’ve used GNOME Boxes here to make our lives a lot easier.  Now KDE are also joining the party with Karton, a project which will deliver what looks very similar to Boxes in the KDE desktop.

The news comes in a post from Derek Lin, and shows us what work has already been done as well as a roadmap for future work. At the moment it’s in no way production ready and it only works with QEMU, but it can generate new VMs, run them, and capture their screens to a desktop window. Having no wish to join in any Linux desktop holy wars we look forward to seeing this piece of software progress, as it’s a Google Summer Of Code project we hope there will be plenty more to see shortly.

Still using the commercial option? You can move to open source too!

The Mouse Language, Running On Arduino

Although plenty of us have our preferred language for coding, whether it’s C for its hardware access, Python for its usability, or Fortran for its mathematic prowess, not every language is specifically built for problem solving of a particular nature. Some are built as thought experiments or challenges, like Whitespace or Chicken but aren’t used for serious programming. There are a few languages that fit in the gray area between these regions, and one example of this is MOUSE, which can now be run on an Arduino.

Although MOUSE was originally meant to be a minimalist language for computers of the late 70s and early 80s with limited memory (even for the era), its syntax looks more like a more modern esoteric language, and indeed it arguably would take a Python developer a bit of time to get used to it in a similar way. It’s stack-based, for a start, and also uses Reverse Polish Notation for performing operations. The major difference though is that programs process single letters at a time, with each letter corresponding to a specific instruction. There have been some changes in the computing world since the 80s, though, so [Ivan]’s version of MOUSE includes a few changes that make it slightly different than the original language, but in the end he fits an interpreter, a line editor, graphics primitives, and peripheral drivers into just 2 KB of SRAM and 32 KB Flash so it can run on an ATmega328P.

There are some other features here as well, including support for PS/2 devices, video output, and the ability to save programs to the internal EEPROM. It’s an impressive setup for a language that doesn’t get much attention at all, but certainly one that threads the needle between usefulness and interesting in its own right. Of course if a language where “Hello world” is human-readable is not esoteric enough, there are others that may offer more of a challenge.


Image Credit: Maxbrothers2020