software

88 Articles

The Newlib Embedded C Standard Library And How To Use It

July 19, 2021 by 4 Comments

When writing code for a new hardware platform, the last thing you want to do is bother with the minutiae of I/O routines, string handling and other similarly tedious details that have nothing to do with the actual project. On bigger systems, this is where the C standard library would traditionally come into play.

For small embedded platforms like microcontrollers, resources are often tight enough that a full-blown stdlib won’t fit, which is why Newlib exists: to bring the portability benefits of a standard library to microcontrollers.

Whether you use C, C++ or MicroPython to program an MCU, Newlib is likely there under the hood. Yet how exactly does it integrate with the hardware, and how are system calls (syscalls) for e.g. file and input/output handling implemented? Continue reading “The Newlib Embedded C Standard Library And How To Use It” →

Cracking A GBA Game With NSA Tools

July 16, 2021 by 1 Comment

[Wrongbaud] is a huge fan of Japanese kaiju-style movies, including Godzilla and King Kong. In honor of the release of a new movie, he has decided to tackle a few projects to see how both of these monsters can hold their own against other legendary monsters. In this project, he is using Ghidra, named after another legendary kaiju, against the password system of the Game Boy Advance game Kong: King of Atlantis.

Since this project is a how-to, [wrongbaud] shows how to search Ghidra for existing scripts that might already have the functionality needed for GBA analysis and emulation. When not, he also illustrates how to write scripts to automate code analysis, and then moves on to cracking the level password system on the game.

The key to finding the passwords on this game was looking for values in the code that were seven characters long, and after some searching [wrongbaud] is finally able to zero in on the code responsible for handling passwords. Once found a brute force method was automated to find viable passwords, and from there the game was officially pwned. For anyone interested in security, reverse engineering, or just the way that binaries work, it’s quite the detailed breakdown. Of course, it’s not the only example we have seen that uses this software tool to extract passwords.

USB Comes To The ESP32

March 26, 2021 by 21 Comments

Since the ESP8266 came on the scene a few years ago and revolutionized the way microcontrollers communicate with other devices, incremental progress on this chip has occurred at a relatively even pace. First there was the realization that code could be run on the chip itself. Next the ESP32 was released which built more on that foundation. The next step in that process of improvement may be here now as well, with this project which turns the ESP32 into a USB host.

USB is not a native feature on all microcontrollers or even Arduino-compatible boards. While some do have it built in like those based on the 32u4 for example, most either don’t have it at all or rely on a separate on-board chip to do some form of translating. The ESP32 is lacking this advanced feature so the USB needs to be cobbled together from scratch if you want this specific board to be able to interface directly with peripherals. This project does just that, allowing for four USB 1.1 devices to be connected directly to the ESP32 without a separate dedicated chip.

If you’ve been waiting for USB on this tiny, capable microcontroller this might be your chance to try it out. All of the project’s code is available on the project page. And, while it is limited in scope, it’s easily able to handle a keyboard or mouse. This might be a more cost-effective way of doing something like a KVM switch rather than doing it with three Arduinos.

 

Lightweight OS For Any Platform

March 22, 2021 by 36 Comments

Linux has come a long way from its roots, where users had to compile the kernel and all of the other source code from scratch, often without any internet connection at all to help with documentation. It was the wild west of Linux, and while we can all rely on an easy-to-install Ubuntu distribution if we need it, there are still distributions out there that require some discovery of those old roots. Meet SkiffOS, a lightweight Linux distribution which compiles on almost any hardware but also opens up a whole world of opportunity in containerization.

The operating system is intended to be able to compile itself on any Linux-compatible board (with some input) and yet still be lightweight. It can run on Raspberry Pis, Nvidia Jetsons, and x86 machines to name a few, and focuses on hosting containerized applications independent of the hardware it is installed on. One of the goals of this OS is to separate the hardware support from the applications, while being able to support real-time tasks such as applications in robotics. It also makes upgrading the base OS easy without disrupting the programs running in the containers, and of course has all of the other benefits of containerization as well.

It does seem like containerization is the way of the future, and while it has obviously been put to great use in web hosting and other network applications, it’s interesting to see it expand into a real-time arena. Presumably an approach like this would have many other applications as well since it isn’t hardware-specific, and we’re excited to see the future developments as people adopt this type of operating system for their specific needs.

Thanks to [Christian] for the tip!

Guitar Effects With No (Unwanted) Delay

March 15, 2021 by 22 Comments

MIDI has been a great tool for musicians and artists since its invention in the 1980s. It allows a standard way to interface musical instruments to computers for easy recording, editing, and production of music. It does have a few weaknesses though, namely that without some specialized equipment the latency of the signals through the various connected devices can easily get too high to be useful in live performances. It’s not an impossible problem to surmount with the right equipment, as illustrated by [Philip Karlsson Gisslow].

The low-latency MIDI interface that he created is built around a Raspberry Pi Pico. It runs a custom library created by [Philip] called MiGiC which specifically built as a MIDI to Guitar interface. The entire setup consists of a preamp to boost the guitar’s signal up to 3.3V where it is then fed to the Pi. This is where the MIDI sampling is done. From there it sends the information to a PC which is able to play the sound back quickly with no noticeable delay.

[Philip] also had to do a lot of extra work to port the software to the Pi which lacks a lot of the features of its original intended hardware on a Mac or Windows machine, and the results are impressive, especially at the end of the video where he uses the interface to play a drum machine via his guitar. And, while MIDI is certainly a powerful application for a guitarist, we have also seen the Pi put to other uses in this musical realm as well.

Continue reading “Guitar Effects With No (Unwanted) Delay” →

Circuit Impedance Calculations Without Cumbersome Simulations

March 2, 2021 by 11 Comments

Using circuit simulating software like SPICE can be a powerful tool for modeling the behavior of a circuit in the real world. On the other hand, it’s not always necessary to have all of the features of SPICE available all the time, and these programs tend to be quite expensive as well. To that end, [Wes Hileman] noticed an opportunity for a specific, quick method for performing impedance calculations using python without bulky, expensive software and came up with a program which he calls fastZ.

The software works on any network of passive components (resistors, capacitors, and inductors) and the user can specify parallel and series connections using special operators. Not only can the program calculate the combined impedance but it can perform frequency analysis at a specified frequency or graph the frequency response over a wide range of frequencies. It’s also running in python which makes it as simple as importing any other python package, and is also easy to implement in any other python program compared to building a simulation and hoping for the best.

If you find yourself regularly drawing Bode plots or trying to cobble together a circuit simulation to work with your python code, this sort of solution is a great way to save a lot of headache. It is possible to get the a piece of software like SPICE to to work together with other python programs though, often with some pretty interesting results.

Fixing The Only Thing That’s Slow About Grand Theft Auto V

March 2, 2021 by 13 Comments

The driving, crime, and general mayhem game Grand Theft Auto V is something of a phenomenon that has lasted for the last seven or more years. Whether following the in-game missions, driving around like a hooligan for fun or performing crazy stunts, the depth of detail in its landscapes and the continual improvements to gameplay that have arrived over the years have assured it a massive following across multiple platforms. The game is not without its problems though, one of which is an unreasonably long loading time for its online version. This annoyed [T0st] to the extent that it was worth the effort of looking under the hood to find out where the problem lay.

It was evident that for PC users the effect varied depending on the hardware present. Furthermore AMD processors seemed worse-hit than Intel ones, and indeed they found an entire core maxed out by a couple of processes during the wait. Some diagnostics and disassembly led the trail to some string processing code which was identified as a JSON parser. This was not simply parsing the JSON but also performing a check for token uniqueness in an extremely inefficient manner, causing the whole process to be extremely slow. Sone nifty patching in a DLL containing a much more efficient function with a cache for unique values saved the day, and delivered an impressive 70% speed-up. It’s to be hoped that the game’s developers will take note, and a future GTA V update will deliver a fix.

Driving a car from a third-person viewpoint in a game like GTA V is a hoot. In real life though, not so much.

Thanks [Thanatos Erberus] for the tip.