Raspberry Pi And The Story Of SD Card Corruption

March 9, 2022 by 107 Comments

Tales of Raspberry Pi SD card corruption are available online by the fistful, and are definitely a constant in Pi-adjacent communities. It’s apparent that some kind of problems tend to arise when a Raspberry Pi meets an SD card – which sounds quite ironic, since an SD card is the official and recommended way of booting a Pi. What is up with all of that?

I can start with a history lesson. Back when Raspberry Pi launched in 2012 – which is now 10 years ago – there were SD card controller driver problems, which makes sense given the wide variety of SD cards available out there. They were verifiably fixed one by one at some point in time, as debugging goes, their impact decreased and bugs with individual cards got smoothed over. This is how the “Pi SD card corruption” meme was originally born; however, if the problems were to end there, so would the meme. Yet, tales of broken SD cards plague us to this day – way less severe than they were in the beginning, but pronounced enough that you’ll see people encounter them every now and then.

Over the years, a devoted base of Pi SD card haters has grown. Their demand has been simple – Raspberry Pi has to get an ability to boot from something else, in large part because of corruption reasons, but also undeniably because of speed and capacity/cost limitations of SD cards. Thanks to their demands and work, we’ve seen a series of projects grow from unofficial efforts and hacks into officially supported Raspberry Pi abilities – USB boot being initially more of a workaround but now something you can enable out of the box, SSD-equipped Pi enclosures becoming more of a norm, and now, NVMe boot appearing on the horizon. Every few years, we get a new way to boot a Pi. Continue reading “Raspberry Pi And The Story Of SD Card Corruption” →

When A Single Bit Was Enough, Into The Sound Of The ZX Spectrum

January 20, 2022 by 8 Comments

It’s normal for a computer in 2022 to come with a fully-featured sound card containing a complete synthesizer as well as high-quality PCM sound recording and playback. It’s referred to as a sound card after the way the hardware first appeared in the world of PCs, but in fact it’s now considered so essential as to be a built-in part of most mainboards. There was a time when computers boasted considerably less impressive sound hardware, and among the chorus of SIDs and AY chips of the perhaps the least well-featured was the original Sinclair ZX Spectrum. Its one-bit sound, a single line on an I/O port, is the subject of a thorough investigation from [Forgotten Computer]. It’s a long video which we’ve placed below the break, but for those with an interest in 8-bit music it should make a for a fascinating watch.

For Sir Clive Sinclair the 1-bit audio must have been welcome as it removed the need for an expensive sound chip and kept the Spectrum to its low price point, but on the face of it there was little more it could do than create simple beeps using Sinclair BASIC’s built-in BEEP command. The video gives us an in-depth look at how interleaving and PWM could be used to create much more complex sounds such as the illusion of multiple voices and even sampled sounds. In particular his technique of comparing the audio output with its corresponding pin on the Sinclair ULA shows the effect of the machine’s simple low-pass filter, though the music was often so close to the edge of what the interface could do that aliasing sounds are often very obvious.

As he demonstrates the various ingenious techniques that game and demo developers used to extract performance from such limited hardware that could even try to compete with the more sophisticated machines even at the same time as their code was running whatever was on the screen, it’s difficult not to come away with immense respect for their skills. If you’ve ever experimented with computer audio then you should try hardware this simple for yourself.

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A Deep Dive Into The Sound Of An Apple II

October 14, 2021 by 21 Comments

A major part of the retrocomputing scene for many of us lies in the world of chiptunes, music created either using original retrocomputing hardware or in the style of those early synthesiser chips. There’s one machine we don’t hear much about among all this though, and that’s the Apple II. Though probably one of the most expandable of all the 8-bit home computers, it lacked a sound channel beyond a speaker hooked up to a memory location port so any complex sound work had to be done via an add-on card. It’s something [Nicole Branagan] has investigated in depth, as she demonstrates first the buzz from the speaker and then what must have been an object of extreme desire back in the day, a Mockingboard sound card.

Her card is not an original but a modern recreation using the same hardware, which is to say a pair of 6522 VIA port chips, each driving an AY-3-8910 audio chip. This is already a familiar device to those who have heard an Amstrad CPC, a later Sinclair Spectrum or, an MSX, and in the Apple it delivers an impressive stereo sound thanks to both channels being present. Interestingly though, it delivers a far smoother output than an MSX playing the same music, probably because of a superior filtering circuit.

She wraps up with a discussion of coding on the Apple for the AY, and how to best accommodate the card on the later Apple IIgs. If the AY chip catches your interest, it’s also easy to drive from a microcontroller.

Homebrew Sounder Maps The Depths In Depth

September 6, 2021 by 10 Comments

For those who like to muck around in boats, there’s enough to worry about without wondering if you’re going to run aground. And there’s really no way to know that other than to work from charts that show you exactly what lies beneath. But what does one do for places where no such charts exist? Easy — make your own homebrew water depth logger.

Thankfully, gone are the days when an able seaman would manually deploy the sounding line and call out the depth to the bottom. [Neumi]’s sounding rig uses an off-the-shelf sonar depth sounder, one with NMEA, or National Marine Electronic Association, output. Combined with a GPS module and an Arduino with an SD card, the rig can keep track not only of how much water is below it, but exactly where the measurement point is. The whole thing is rigged up to an inflatable dinghy which lets it slowly ply the confines of a small marina, working in and out of the nooks and crannies. A bit of Python and matplotlib stitches that data together into a bathymetric map of the harbor, with pretty fine detail. The chart also takes the tides into account, as the water level varies quite a bit over the four hours it takes to gather all the data. See it in action in the video after the hop.

There’s something cool about revealing the mysteries of the deep, even if they’re not that deep. Want to go a little deeper? We’ve seen that before too.

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Your 1958 Punch Card Machine Tested Tubes

June 15, 2021 by 12 Comments

We think of punched cards as old-fashioned, but still squarely part of the computer age. Turns out, cards were in use way before they got conscripted by computers. Jacquard looms are one famous example. The U.S. Census famously used punched cards for tabulating the census without anything we’d consider a computer. But in the 1950s, you might have had a punched card machine on your electronics workbench. The Hickok Cardmatic was a tube tester with a difference.

About Tube Testers

While you, as a Hackaday reader, might tear into a busted TV at your house and try to fix it, most people today will either scrap a bad set or pay someone to fix it. That’s fine today. TVs are cheap and rarely break, anyway. But this hasn’t always been the case.

In the “good old days” your expensive TV broke down all the time. Most of the parts were reliable, but the tubes would wear out. If you were the kind of person who would change your own oil, you’d probably look to see if you could spot a burned out tube and try replacing it. If you couldn’t spot it, you’d pull all the tubes out. If you were lucky, there was a diagram glued inside the cover that showed where they all went back. Then you took them to the drugstore.

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TNDLPT Brings Tandy Sound To Any DOS Computer

May 27, 2021 by 9 Comments

The Tandy 1000, among other contemporary computers and consoles of the 1980s, used the Texas Instruments SN76489 for its sound and musical output. This venerable sound chip can now be used on virtually any DOS machine, as long as it has a parallel port – thanks to the TNDLPT adapter!

The adapter consists of the SN76489, hooked up to the parallel port so that it can be addressed by the host computer via a DOS Terminate and Stay Resident program acting as a driver. With the TSR loaded, classic DOS games can be used with the TNDLPT sound output by simply selecting the Tandy 1000 soundcard at install. It can also be used in a variety of other ways, such as with the TNDY tracker for music creation, or the SBVGM soundtrack player.

For those eager to hear the soaring 3 voices (and one noise channel!) of the SN76489 once again, this is a great way to do it, with kits available on the Serdashop site for those wishing to solder up their own. Alternatively, get a different vibe with the OPL2 instead. Video after the break.

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New Part Day: SD NAND Are Surface Mount Chips That Work Like An SD Card

December 29, 2020 by 71 Comments

SD cards have long been a favorite with microcontroller hobbyists. Cheap, readily available, and easily interfaced, they remain a staple for small projects that need to store a lot of data. Now, they’re available in chip form! These are known as SD NAND parts that emulate the SD card interface itself.

[LadyAda] recently gave them a test-drive after spotting a tweet from [Greg Davill] (who we’re familiar with thanks to his excellent LED cubes). The devices are manufactured by XTX Technology and available from LCSC in a range of 1, 2, 4, and 8 GB sizes. [Ivan Grokhotkov] also illuminated a similar device from another maker in a reply to [Greg’s] original tweet, so there may be more sources out there.

These chips come in standard LGA8 surface mount package and can be easily soldered to a board, offering mechanical and manufacturing benefits versus using a normal SD or microSD card in a slot-type connector. Also, unlike other SMD flash memory parts, they handle all the file system details and wear levelling for you! With the inflation of SD card sizes, it’s also difficult to find these on the shelf in normal cards these days.

[Adafruit] plan to have a breakout for these parts out soon with a level shifter included for ease of use. We can imagine these chips finding their way into all manner of datalogger projects, since they can be ordered with other parts and permanently soldered into a design. If you’ve got a particularly good idea where these chips would prove useful, sound off in the comments. Video after the break.

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