Upgrading the memory in a computer is usually a straightforward case of swapping out a few DIMMs or SODIMMs, with the most complex task being to identify the correct type of memory from the many available. But sometimes a laptop manufacturer can be particularly annoying, and restrict upgradability by soldering the RAM chips directly to the board. Upgrading memory should then be impossible, but this reckons without the skills of [Greg Davill], who worked through the process on his Dell XPS13.
The write-up is a fascinating primer on how DRAM identification works, which for removable DIMMs is handled by an onboard FLASH chip containing the details of the chips on board. A soldered-on laptop has none of these, so instead it employs a series of resistors whose combination tells the BIOS what memory to expect. Some research revealed their configuration, at which point the correct chips were sourced. Surprisingly it’s not as easy as one might expect to buy small quantities of some RAM chips, but he was eventually able to find some via AliExpress. An aside is how he checked the chips he received for fakes, including the useful tip of hiring a dentist to take an x-ray.
The final step is the non-trivial task of reballing and reworking the new BGAs onto the board, before testing the laptop and finding the process to be a success. We’ll leave you with his final words though: “But next time I think I’ll just buy the 16GB variant upfront.“.
We’ve seen quite a lot of [Greg]’s work here at Hackaday, one of his most recent was this amazing LED D20.
I’m excited to share the news that Elecia White will deliver a keynote talk at the Hackaday Remoticon in just a few short weeks. Get your free ticket now!
Elecia is well-known throughout the embedded engineering world. She literally wrote the book on it — or at least a book on it, one I have had in my bedside table for reference for years: O’Reilly’s Making Embedded Systems: Design Patterns for Great Software. She hosts the weekly Embedded podcast which has published 390 episodes thus far. And of course Elecia is a principal embedded software engineer at Logical Elegance, Inc working on large autonomous off-road vehicles and deep sea science platforms.
For her keynote, Elecia plans to unwrap the secrets often overlooked in the memory map file generated when compiling a program for a microcontroller. Anyone who has written code for these mighty little chips has seen the .map files, but how many of us have dared to really dive in?
Elecia will use a nifty metaphor for turning the wall of text and numbers into a true map of the code. That metaphor makes the topic approachable for everyone with at least a rudimentary knowledge of how embedded systems work, and even the grizzliest veteran will walk away with tips that help when optimizing for RAM usage and/or code space, updating firmware (with or without a bootloader), and debugging difficult crash bugs.
The Call for Proposals closed a few days ago. So far we’ve made two announcements about the accepted talks and we’ll make two more, this Thursday and next. But there’s no reason to wait. With Elecia White, Jeremy Fielding, and Keith Thorne presenting keynotes, and some superb social activities soon to be unveiled, this is an event not to be missed!
Remoticon is free to all, just head over and grab a ticket! If you want something tangible to remember the weekend by you can grab one of the $25 tickets that scores you a shirt, but either option gets you all the info you need to be at every virtual minute of the conference.
Finding broken test gear and fixing it up to work again is a time-honored tradition among hackers. If you’re lucky, that eBay buy will end up being DOA because of a popped fuse or a few bad capacitors, and a little work with snips and a soldering iron will earn you a nice piece of test gear and bragging rights to boot.
Some repairs, though, are in a class by themselves, like this memory module transplant for a digital scopemeter. The story began some time ago when [FeedbackLoop] picked up a small lot of broken Fluke 199C scopemeters from eBay. They were listed as “parts only”, which is never a good sign, and indeed the meters were in various states of disassembly and incompleteness.
The subject of the video below was missing several important bits, like a battery and a power connector, but most critically, its memory module. Luckily, the other meter had a good module, making reverse engineering possible. That effort started with liberating the two RAM chips and two flash chips, all of which were in BGA packages, from the PCB. From there each chip went into a memory programmer to read its image, which was then written to new chips. The chip-free board was duplicated — a non-trivial task for a six-layer PCB — and new ones ordered. After soldering on the programmed chips and a few passives, the module was plugged in, making the meter as good as new.
Homebrew 8-bit computers tend to have fairly limited displays, often one or more seven-segment displays and an array of LEDs to show the values of RAM or perhaps some other states of the computer. [Duncan] is in the process of building just such an computer, but wondered if there was a way to create a more visually appealing display while still keeping the computer true to its 8-bit roots. With some interesting TTL logic he was able to create this addressable RGB LED display to some remarkable results.
The array works by controlling the WS2812B LED strips with a specific timing cycle which was pioneered by [Tim] for a different project. [Tim] was able to perform this timing cycle with some simple Assembly code, which means that [Duncan] could convert that code into TTL gate logic relatively easily. Using 74LS02 NOR chips gets the job done as far as timing goes, and the pulses are then fed into a shift register and support logic which then creates the signal for the LED strips.
When everything is said and done, [Duncan] has a fully addressable 16×16 RGB LED array as a display for his 8-bit computer without violating any of his design principles and keeping everything to discrete TTL logic chips and a stick of RAM. It’s a unique method of display that might go along really well with any other homebrew computer like this one that’s also built with 74LS chips.
We often see press releases and announcements about the next big technology in batteries, memory, displays, capacitors, or any of a number of other things. Usually we are suspicious since we typically don’t see any of this new technology in the marketplace over any reasonable timescale. So when we read about correlated-electron memoryCerfe Labs, we had to wonder if it would be more of the same. IOur suspicions may be justified of course, but it is telling that the company is a spin-off from ARM, so that gives them some real-world credibility.
Correlated-electron RAM or CeRAM is the usual press release material. Nonvolatile, smaller than SRAM, and fast. It sounds as though it could replace the SRAM in PC caches, for example, and take up less die space on the CPU chip. The principle is a bit odd. When electrons are forced together in certain materials, the properties of the material can change. This Mott transition (named after the inventor [Neville Mott]) can take carbon-doped nickel oxide and switch it from its natural electrical insulating state to a conducting state and back again.
We know what you’re thinking: this is yet another one of those “Gut the retro gear for its cool old case and then fill it up with IoT junk” projects. Well, rest assured that extending and enhancing this 1970s computer trainer is very much an exercise in respecting the original design, and while there’s a Pi inside, it doesn’t come close to spoiling the retro goodness.
Like many of a similar vintage as [Scott M. Baker], the Heathkit catalog was perhaps only leafed through marginally less than the annual Radio Shack catalog. One particularly desirable Heathkit item was the ET-3400 microcomputer learning system, which was basically a 6800-based computer surrounded by a breadboarding area for experimentation. [Scott] got a hold of one of these, but without the optional expansion accessory that would allow it to do interesting things such as running BASIC or even supporting a serial port. So [Scott] decided to roll his own expansion board.
The expansion card that [Scott] designed is not strictly a faithful reproduction, at least in terms of the original BOM. He turned to more modern — and more readily available — components, but still managed to provide the serial port, cassette interface, and RAM/ROM expansion of the original unit. The Raspberry Pi is an optional add-on, which just allows him to connect wirelessly if he wants. The card fits into a 3D-printed case that sits below the ET-3400 and maintains the original trainer’s look and feel. The longish video below shows the build and gives a tour of the ET-3400, both before and after the mods.
It looks as though trainers like these and other artifacts from the early days of the PC revolution are getting quite collectible. Makes us wish we hadn’t thrown some things out.
At any given time I’m likely to have multiple projects in-flight, by which of course I mean in various stages of neglect. My current big project is one where I finally feel like I have a chance to use some materials with real hacker street cred, like T-slot extruded aluminum profiles. We’ve all seen the stuff, the “Industrial Erector Set” as 80/20 likes to call their version of it. And we’ve all seen the cool projects made with it, from CNC machines to trade show displays, and in these pandemic times, even occasionally as sneeze guards in retail shops.
Aluminum T-slot profiles are wonderful to work with — strong, lightweight, easily connected with a wide range of fasteners, and infinitely configurable and reconfigurable as needs change. It’s not cheap by any means, but when you factor in the fabrication time saved, it may well be a net benefit to spec the stuff for a project. Still, with the projected hit to my wallet, I’ve been looking for more affordable alternatives.
My exploration led me into the bewilderingly rich world of aluminum extrusions. Even excluding mundane items like beer and soda cans, you’re probably surrounded by extruded aluminum products right now. Everything from computer heatsinks to window frames to the parts that make up screen doors are made from extruded aluminum. So how exactly is this ubiquitous stuff made?