Flash Programmer Shows Some Nifty Tricks

November 5, 2023 by 13 Comments

A handy tool to have on the bench is a Flash chip programmer, and the ones based around the CH341A USB bus converter chip are readily available. But the chip is capable of so much more than simply programming nonvolatile memory, so [Tomasz Ostrowski] has created a utility program that expands its capabilities. The software provides easy access to a range of common i2c peripherals. He’s got it talking to smart batteries, GPIOs, environmental sensors, an OLED display, and even an FM radio module. The code can all be found in a GitHub repository. The software is Windows-only so no fun and games for Linux users yet — but since it’s open source, new features are just a pull request away.

The CH341A is much more than an i2C controller, it also supports a surprising range of other interfaces including SPI, UARTs, and even a bidirectional parallel printer port. Maybe this software will serve to fire the imagination of a few others, and who knows, we could see more extended use of this versatile chip. Oddly we’ve featured these programmer boards before, though in a tricky flashing job.

Open Source Key Programmer For HiTag2 Keys

October 28, 2023 by 9 Comments

Hitag transponders have been used in a wide variety of car keys as a protective measure against hot-wiring and theft. They’re also a reason why it’s a lot more expensive to get car keys duplicated these days for many models that use this technology. However, there is now an open source programmer that works with these transponder keys, thanks to [Janne Kivijakola].

The hack uses an old reader device salvaged from a Renault in a scrapyard, hooked up to an Arduino Mega 2560 or Arduino Nano. With this setup, key transponders can be programmed via a tool called AESHitager, which runs on Windows. It’s compatible with a variety of Hitag transponders, including Hitag2, Hitag3, and Hitag AES, along with the VVDI Super Chip and certain types of BMW keys.

If you’ve been having issues with coded keys, this project might just be what you need to sort your car out. Everything you need is available on GitHub for those wishing to try this at home. We’ve seen some interesting hacks in this space before, too. Video after the break.

Continue reading “Open Source Key Programmer For HiTag2 Keys” →

Contrary View: Chatbots Don’t Help Programmers

June 8, 2023 by 67 Comments

[Bertrand Meyer] is a decided contrarian in his views on AI and programming. In a recent Communications of the ACM blog post, he reveals that — unlike many others — he thinks AI in its current state isn’t very useful for practical programming. He was responding, in part, to another article from the ACM entitled “The End of Programming,” which, like many other articles, is claiming that, soon, no one will write software the way we do and have done for the last few decades. You can see [Matt Welsh] describe his thoughts on this in the video below. But [Bertrand] disagrees.

As we have also noted, [Bretrand] says:

“AI in its modern form, however, does not generate correct programs: it generates programs inferred from many earlier programs it has seen. These programs look correct but have no guarantee of correctness.”

Continue reading “Contrary View: Chatbots Don’t Help Programmers” →

Linux Fu: The Shell Forth Programmers Will Love

February 8, 2023 by 28 Comments

One of the most powerful features of Unix and Linux is that using traditional command line tools, everything is a stream of bytes. Granted, modern software has blurred this a bit, but at the command line, everything is text with certain loose conventions about what separates fields and records. This lets you do things like take a directory listing, sort it, remove the duplicates, and compare it to another directory listing. But what if the shell understood more data types other than streams? You might argue it would make some things better and some things worse, but you don’t have to guess, you can install cosh, a shell that provides tools to produce and work with structured data types.

The system is written with Rust, so you will need Rust setup to compile it. For most distributions, that’s just a package install (rust-all in Ubuntu-like distros, for example). Once you have it running, you’ll have a few new things to learn compared to other shells you’ve used. Continue reading “Linux Fu: The Shell Forth Programmers Will Love” →

Turning A Microchip MPLAB Snap Into A UDPI AVR Programmer

December 26, 2022 by 20 Comments

The Unified Program and Debug Interface (UPDI) is Microchip’s proprietary interface for programming and on-chip debugging, and has become the standard on AVR MCUs after Microchip’s purchase of Atmel. Being a proprietary interface means that even entry-level programmers like the Atmel-ICE are rather expensive at over $100. That’s when for [Scott W Harden] the question arose of whether the much cheaper MPLAB Snap board (~$34) could be used as well for AVR UDPI purposes.

The stages of grief that [Scott] went through before he had it working involved among others the updating of the MPLAB Snap board firmware, getting yelled at by the Microchip Studio IDE when attempting to use the Snap for AVR MCU programming, and ultimately fixing the board following the relevant Microchip Engineering Technical Note (ETN #36) that specifies the removal of a 4.7 kΩ pull-down resistor (R48) on the Snap board. This allows the UDPI line to be pulled high by the MCU.

As the ETN notes, an external pull-up may also be used to override the pull-down, which would leave the ICSP functionality of of the Snap intact. As [Scott] mentions in his conclusion, it feels as if UDPI AVR support with the Snap is really an afterthought for Microchip. Meanwhile there are also more DIY solutions as [Scott] adds, which are useful for just flashing the MCU. An example is with a USB-TTL serial adapter and pymcuprog.

The problem with DIY solutions like jtag2updi, ftdi2updi, and their kin is the effort required to assemble them, and the uncertainty of long-term support as the UPDI ecosystem keeps evolving with new devices and new features. The MPLAB Snap with resistor mod may be just that middle ground between an Atmel-ICE and reverse-engineered OSS projects.

(Featured image: MPLAB Snap resistor mod illustrated, from Microchip ETN #36)

The 10 Kinds Of Programmers That Use Calcutron-33

December 7, 2022 by 18 Comments

It is interesting how, if you observe long enough, things tend to be cyclical. Back in the old days, some computers didn’t use binary, they used decimal. This was especially true of made up educational computers like TUTAC or CARDIAC, but there was real decimal hardware out there, too. Then everyone decided that binary made much more sense and now it’s very hard to find a computer that doesn’t use it.

But [Erik] has written a simulator, assembler, and debugger for Calcutron-33, a “decimal RISC” CPU. Why? The idea is to provide a teaching platform to explain assembly language concepts to people who might stumble on binary numbers. Once they understand Calcutron, they can move on to more conventional CPUs with some measure of confidence.

To that end, there are several articles covering the basic architecture, the instruction set, and how to write assembly for the machine. The CPU has much in common with modern microprocessors other than the use of decimal throughout.

There have been several versions of the virtual machine with various improvements and bug fixes. We’ll be honest: we admire the work and its scope. However, if you already know about binary, this might not be your best bet. What’s more is, maybe you should understand binary before tackling assembly language programming, at least in modern times. Still, it does cover a lot of ground that applies regardless.

Made-up computers like TUTAC and CARDIAC were all the rage when computer time was too expensive to waste on mere students. There was also MIX from computer legend Donald Knuth.

This DIY UPDI Programmer Is Nice And Cheap

April 15, 2022 by 3 Comments

[Daumemo] likes experimenting with DIY electronics, and like many people, eventually ran across an AVR microcontroller with a Unified Program and Debug Interface (UPDI). One option is of course to purchase an UPDI programmer, but an even better solution was to make a DIY USB version from nice, cheap parts.

Programming an Attiny404 over the UPDI interface.

UPDI is an interface for external programming and on-chip debugging of microcontrollers, and [Daumemo]’s solution is based on the jtag2updi project. It combines an Arduino Nano (in this case, a clone) with a single resistor, a single capacitor, and a six pin angled header (with a cleverly bent pin) to enable programming UPDI devices over a USB connection. [Daumemo] is happy to report that the device works just fine in both Microchip Studio with AVRDUDE, or PlatformIO.

Is an Arduino Nano a bit overpowered in this role? Maybe, but the price is certainly right. There’s no need for a custom PCB either, since everything can be soldered direct to the Nano board. A matching 3D printed enclosure is about all that’s needed to make a robust and reliable DIY USB UPDI programmer out of a handful of parts, and that sounds good to us.

On the other hand, if you do find yourself making custom PCBs, you may be interested in another of [Daumemo]’s DIY projects: a printable structure to turn a rotary tool into a PCB drill press.