Back in the 1970s, there were a huge variety of esoteric LED displays on the market. One of those was the DIP-packaged TIL311 from Texas Instruments, capable of displaying hexadecimal, from 0-9 and A-F. While these aren’t readily available anymore, the deep red plastic packages had some beauty to them, so [Alex] set about making a modern recreation.
The build consists of a small PCB fitted with 20 LEDs, and a STM8S microcontroller to run the show. This can be used to emulate the original decoder logic on the TIL311, or programmed with other firmware in order to test the display or enable other display functions. Where the project really shines however is in the visual presentation. [Alex] has been experimenting with potting the hardware in translucent red resin to properly emulate the look of the original parts, which goes a long way to getting that cool 70s aesthetic. Attention to detail is top notch, with [Alex] going so far as to carefully select pins that most closely match the square-cut design on the original TIL311 part.
We like simulation software. Texas Instruments long offered TINA, but recently they’ve joined with Cadence to make OrCAD PSpice available for free with some restrictions. You’ve probably heard of PSpice — it’s widely used in academia and industry, but is usually quite costly. You can see a promotional overview video below.
The program requires registration and an approval step to get a license key. The downloaded program has TI models along with other standard models. There seem to be few limits as long as you stick to the supplied library. According to the datasheet, there are no size or simulation complexity limitations in that case. If you want to use other models, you can, but that’s where the limitations hit you:
There is no limitation of how many 3rd party models can be imported into the design. However, if 3rd party models are imported, a user will be able to plot a maximum of 3 signals at a time of their choice when any 3rd party model is imported from web.
We aren’t completely sure what “from web” means there, but presumably they just mean from other sources. In any event, you still get AC, DC, and transient analysis with plenty of options like worst-case timing analysis. Mixed signal designs are supported and there is a wealth of data plotting options, as you would expect.
This is a great opportunity to drive some serious software that is widely used in the industry. The only thing that bummed us out? It runs under Windows. We couldn’t get it to work under Wine, but a Windows 10 VM handled it fine, although we really hate running a VM if we don’t have to.
Still, the price is right and it is a great piece of software. We also liked the recent Micro-Cap 12 release, but we don’t expect any updates for that. Of course, LTSpice is quite capable, too.
While repairing a real-time clock module for a 1970s HP computer that had been damaged by its leaky internal battery, [CuriousMarc] began to suspect that maybe the replacement clock chips which he had sourced from a seller in China were the reason why the module still wasn’t working after the repairs. This led him down the only obvious path: to decap and inspect both the failed original Ti chip and the replacement chip.
The IC in question is the Texas Instruments AC5948N (along with the AC5954N on other boards), which originally saw use in LED watches in the 1970s. HP used this IC in its RTC module, despite it never having been sold publicly. This makes it even more remarkable that a Chinese seller had the parts in stock. As some comments on the YouTube video mention, back then there wasn’t as much secrecy around designs, and it’s possible someone walked out of the factory with one of the masks for this chip.
Whether true or not, as the video (also included after the break) shows, both the original 1970s chip and the China-sourced one look identical. Are they original stock, or later produced from masks that made their way to Asia? We’ll probably never know for sure, but it does provide an exciting opportunity for folk who try to repair vintage equipment.
We use a microcontroller without a second thought, in applications where once we might have resorted to a brace of 74 logic chips. But how many of us have spared a thought for how the microcontroller evolved? It’s time to go back a few decades to look at the first commercially available microcontroller, the Texas Instruments TMS1000.
Imagine A World Without Microcontrollers
It’s fair to say that without microcontrollers, many of the projects we feature on Hackaday would never be made. Those of us who remember the days before widely available and easy-to-program microcontrollers will tell you that computer control of a small hardware project was certainly possible, but instead of dropping in a single chip it would have involved constructing an entire computer system. I remember Z80 systems on stripboard, with the Z80 itself alongside an EPROM, RAM chips, 74-series decoder logic, and peripheral chips such as the 6402 UART or the 8255 I/O port. Flashing an LED or keeping an eye on a microswitch or two became a major undertaking in both construction and cost, so we’d only go to those lengths if the application really demanded it. This changed for me in the early 1990s when the first affordable microcontrollers with on-board EEPROM came to market, but by then these chips had already been with us for a couple of decades.
It seems strange to modern ears, but for an engineer around 1970 a desktop calculator was a more exciting prospect than a desktop computer. Yet many of the first microcomputers were designed with calculators in mind, as was for example the Intel 4004. Calculator manufacturers each drove advances in processor silicon, and at Texas Instruments this led to the first all-in-one single-chip microcontrollers being developed in 1971 as pre-programmed CPUs designed to provide a calculator on a chip. It would take a few more years until 1974 before they produced the TMS1000, a single-chip microcontroller intended for general purpose use, and the first such part to go on sale. Continue reading “The TMS1000: The First Commercially Available Microcontroller”→
In 1971, Texas Instruments released something no one else had ever seen before. The TIL305 was an alphanumeric display, powered by LEDs. Sure, the technology of the early 70s meant the LEDs weren’t very bright, and the displays were expensive, but if you want a display that’s simply classic, and relatively low-power, you won’t be able to do better than a vintage alphanumeric LED display.
The vintage, TI-made TIL305 is a printed circuit board that clips into a DIP-14 socket. The LED array is 5×7 pixels, with an extra dot for a decimal point, set on a 0.05″ grid, and a translucent red diffuser. A PCB is easy, and with 0201 LEDs you can get the LED pitch you need. Turning a PCB into a DIP-14 only requires a few machine pin headers, and for the diffuser, this project is using laser cut cast acrylic. It’s simple if you have a pick and place machine or a steady hand, and assembly is a snap.
The final DIYTIL305 boards are being tested right now, but so far the results are great. With the right code on a microcontroller, these displays will blink through the digits 0 through 9, and the alphabet is just a little more code. Since this project is using 0201 LEDs, it also means green, white, blue, orange, and yellow displays are possible, something no one could have dreamed of in 1971.
Graphing calculators are an interesting niche market these days. They’re relatively underpowered, and usually come with cheap, low resolution screens to boot. They remain viable almost solely due to their use in education and the fact that their limited connectivity makes them suitable for use in exams. The market is starting to hot up, though – and TI have recently been doing some interesting work with Python on their TI-83.
Rumor has it that TI have been unable to get Python to run viably directly on the TI-83 Premium CE. This led to the development of the TI-Python peripheral, which plugs into the calculator’s expansion port. This allows users to program in Python, with the TI-Python doing the work and the calculator essentially acting as a thin client. The chip inside is an Atmel SAMD21E18A-U, and is apparently running Adafruit’s CircuitPython platform.
This is a hack in its early days, so it’s currently more about building a platform at this stage rather then building fully-fledged projects just yet. We’re fully expecting to see Twitter clients and multiplayer games hit the TI-83 platform before long, of course. When you’ve done it, chuck us a link on the tip line.
Way back in the 1980s, in the heyday of the personal computer revolution, Texas Instruments were one of the major players. The TI-99/4A was one of their more popular machines, selling 2.8 million units after an epic price war with the Commodore VIC-20. However once it had been discontinued, fans were left wanting more from the platform. Years later, that led [Fabrice] to produce the TI(ny), his take on an upgraded, more integrated TI-99/4A (Google Translate link).
Having spent many years working on these machines, [Fabrice] was very familiar with the official TI schematics – regarding both their proper use and their errors, omissions and inaccuracies. With a strong underlying knowledge of what makes a TI-99/4A tick, he set out to pen his own take on an extended model. [Fabrice] rolls in such features as Atari-compatible joystick ports, slot connectors for PeBOX expansion cards, and an RGB video output. It’s then all wrapped up in a very tidy looking case of somewhat unclear construction; it appears to be modified from an existing small computer case, and then refinished to look almost stock.
The best detail, though? It’s all made with components available in 1983! We see a lot of retro builds that are the equivalent of throwing a modern fuel-injected V8 into a vintage muscle car, and they are fantastic – but this is a project that shows us what was possible way back when.
Overall it’s a tidy build that shows what the TI-99/4A could have been if it was given a special edition model at the end of its life. If you’re looking to relive the glory days of the machine yourself, what better way then firing up the best demo on the platform? As the saying goes – Don’t Mess With Texas.