Using The Pi Pico As ‘Programmable Hardware’ For The Apple II

August 27, 2024 by Lewin Day 8 Comments

When we think of programmable hardware, we think of FPGAs. But they’re not the only option. [Oliver Schmidt] has been exploring how the Raspberry Pi Pico can serve in such a role for the classic Apple II. The talk was presented at the KansasFest event this year, and it’s well worth diving into!

[Oliver] has developed A2Pico. It’s a series of Apple II peripheral cards that are based around the Raspberry Pi Pico, as you might have guessed. [Oliver] has been working in the area since 2021 with one [Glenn Jones], with the duo experimenting with connecting the versatile microcontroller directly to the slot bus of the Apple II. [Ralle Palaveev] then chimed in, developing the A2Pico hardware with solely through-hole components for ease of assembly.

A number of cards have been developed based on A2Pico, including a storage device, a Z80 CP/M card, and a specialized card to play Bad Apple on the IIGS. It’s all thanks to the versatility of the programmable I/O (PIO) peripheral inside the Raspberry Pi Pico. This device enables the Pico to be reprogrammed to handle all sorts of complicated tasks at great speed. This is particularly useful when using it to bit-bang a protocol or talk with another machine, and it serves perfectly well in this role. Basically, by reprogramming the Pico and its PIO, the A2Pico design can become any one of a number of different add-on cards.

It’s well worth diving into this stuff if you’ve ever contemplated building your own peripheral cards for 8-bit and 16-bit machines. We’ve seen some other great add-on cards for vintage machines before, too.

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The Macintosh Plus Sounds Great If You Do Exactly This With It

August 26, 2024 by Lewin Day 3 Comments

The Macintosh Plus is not exactly known as particularly relevant in the worlds of chiptune or electronic music more broadly. That’s not to say it can’t do anything that sounds cool, however. As [Action Retro] demonstrates, it’s got some really impressive tricks up its sleeve if you know what you’re doing.

The video centers around “Music Mouse”, a piece of software created by Laurie Spiegel for the Macintosh Plus all the way back in 1986. Spiegel saw the Macintosh Plus as a potential instrument for musical expression, with the then-innovative mouse as the key human interface.

[Action Retro] shows off the software, which is able to create rather pleasing little melodies with little more than a swish and a swash across the mousepad. The software makes smart use of scales so you’re not forever dodging around dissonant notes, so it’s quite easy to play something beautiful. He then makes things more interesting by pairing the Macintosh Plus with his favorite guitar pedal—the Old Blood Noise Endeavors Sunlight. It’s a dynamic reverb that really opens up the sonic landscape when paired with the Mac Plus. If you’re looking for a weird avant-garde setup to take on stage at your next noise show, this has to be it.

We’re usually used to seeing Nintendo and Commodore products in the retro computer music space. The Mac makes a nice change. Video after the break.

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Everything You Wanted To Know About Early Macintosh Floppies

August 26, 2024 by Al Williams 30 Comments

Using a disk drive today is trivial. But back “in the day,” it was fairly complex both because the drives were simple and the CPUs were not powerful by today’s standards. [Thomas] has been working on a 68000 Mac emulator and found that low-level floppy information was scattered in different places. So he’s gathered it all for us in one place.

Low-level disk access has a lot of subtle details. For example, the Mac calibrates its speed control on boot. If your emulated drive just sets the correct speed and doesn’t respond to changes during calibration, the system will detect that as an error. Other details about spinning disks include the fact that inner tracks are shorter than outer track and may require denser recordings. Laying out sectors can also be tricky since you will lose performance if you, for example, read sector one and then miss sector two and have to wait for it to come back around. Disk sectors are often staggered for this reason.

Adding to the complexity is the controller — the IWM or Integrated Woz Machine — which has an odd scheme for memory mapping I/O. You should only access the odd bytes of the memory-mapped I/O. The details are all in the post.

In a way, we don’t miss these days, but in other ways, we do. It wasn’t that long ago that floppies were king. Now it is a race to preserve the data on them while you still can.

The Famous Computer Cafe Has Now Been Archived Online

August 23, 2024 by Lewin Day 4 Comments

You might think that TV stations or production houses would be great at archiving, but it’s not always the case. Particularly from the public access perspective. However, if you’re a fan of The Famous Computer Cafe, you’re in luck! The beloved series has now been preserved on The Internet Archive!

If you’re not familiar with the show, it was a radio program broadcast from 1983 to 1986. It was pumped out of a variety of radio stations in southern and central California in the period. The creators making sure to keep a copy of each episode in reel-to-reel tape format. For years, these tapes were tragically lost, until archivist [Kay Savetz] was able to recover some of them from a recent property sale. From there, a GoFundMe paid for digitization, and the show has been placed on The Internet Archive with the blessings of the original creators.

This is quite the cultural victory, particularly when you observe the list of guests on the show. Timothy Leary, Bill Gates, Jack Tramiel, and even Douglas Adams made appearances in the recovered recordings. Sadly, though, not all the tapes have been recovered. Episodes with Gene Roddenberry, Robert Moog, and Ray Bradbury are still lost to time.

If you fancy a listen, 53 episodes presently exist on the archive. Take a trip back in time and hear from some technological visionaries—and futurists—speaking their minds at the very beginning of the microcomputer era! If you find any particularly salient gems, don’t hesitate to drop them on the tip line.

Happy Birthday To Dad, Retrocomputer Style

August 22, 2024 by Dan Maloney 3 Comments

For those of us who lived through the early 8-bit computing revolution — the tail end, in our case — it’s hard to believe that there’s a second wave of retrocomputing nostalgia underway. But as this bit-banged TRS-80 birthday bonus pack shows, the first generation did a pretty good job passing the retro torch.

With his father’s 70th birthday coming up and full of “borrowed nostalgia” for the good old days, [Josh Sucher] scored a TRS-80 off eBay and experimented with what could be possible. After 50-odd years, the machine needed a bit of TLC, including a new power supply, some keyboard repairs, and the usual recapping. He also had to soup the machine up a bit, given that its original capabilities were so limited.

Chief among these mods was a rudimentary IP stack thanks to a TRS-IO card, which emulates a lot of functionality of the original TRS-80 Expansion Module and adds an ESP-32 for WiFi capability. This allowed [Josh] to get a neat “Dadbot” chatbot going on the machine, using years of his dad’s text messages to train the model. There’s also a game of Go, an RPG based on his parents’ lives, and a local news and weather app. Most impressive, though, is the bit-banged audio app that uses the TRS-80’s cassette interface to play a passable rendition of “Happy Birthday to You.” The video below has the full demo.

It’s clear that this lengthy project was a labor of love, and we approve of the results. It’s been a long, long time since we first caught wind of the TRS-80 through the Radio Shack catalog, and projects like this make us feel like scratching up one for ourselves to play with.

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Tiny ’90s Laptop Gets Modern Power

August 21, 2024 by Jenny List 19 Comments

The laptop to have here in the 2020s varies depending on who you ask, perhaps a Framework, or maybe a ThinkPad. Back in the 1990s the answer might have included a now-forgotten contender, because in that decade Toshiba made a range of legendarily tough chunky grey machines. Of these the smallest was the Libretto, a paperback book sized clamshell design which was an object of desire. It’s one of these that [Robert’s Retro] has upgraded to use USB-C power instead of the original power brick.

The full video is below the break, and while it first deals with replacing a defective screen, the power part starts just before 22 minutes in. As you’d expect it involves a USP-C PD trigger board, this time at 15 volts. It’s mounted in a small 3D printed adapter to fill the space of the original jack, and requires a tiny notch be removed from the corner of its PCB to fit round the motherboard. The rest of the video deals with reassembling the machine and tending to mishaps with the ageing plastic, but the result is a Libretto with a modern charging port.

Naturally a machine with a Pentium CPU and 32 megabytes of RAM is in of limited use in modern terms, but these Librettos remain very well-designed tiny PCs to this day. It’s great to see them still being modified and upgraded, even if perhaps there’s a limit to how far you can push their computing power. We’ve encountered the Libretto before a few times, such as when one was used to retrieve data from an old Flash card.

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The First Mass Produced DRAM Of The Soviet Union

August 21, 2024 by Maya Posch 8 Comments

KE565RU1A (1985) in comparison with the analogue from AMD (1980)

Although the benefits of semiconductor technology were undeniable during the second half the 20th century, there was a clear divide between the two sides of the Iron Curtain. Whilst the First World had access to top-of-the-line semiconductor foundries and engineers, the Second World was having to get by with scraps. Unable to keep up with the frantic pace of the USA’s developments in particular, the USSR saw itself reduced to copying Western designs and smuggling in machinery where possible. A good example of this is the USSR’s first mass-produced dynamic RAM (DRAM), the 565RU1, as detailed by [The CPUShack Museum].

While the West’s first commercially mass-produced DRAM began in 1970 with the Intel 1103 (1024 x 1) with its three-transistor design, the 565RU1 was developed in 1975, with engineering samples produced until the autumn of 1977. This DRAM chip featured a three-transistor design, with a 4096 x 1 layout and characteristics reminiscent of Western DRAM ICs like the Ti TMS4060. It was produced at a range of microelectronics enterprises in the USSR. These included Angstrem, Mezon (Moldova), Alpha (Latvia) and Exciton (Moscow).

Of course, by the second half of the 1970s the West had already moved on to single-transistor, more efficient DRAM designs. Although the 565RU1 was never known for being that great, it was nevertheless used throughout the USSR and Second World. One example of this is a 1985 article (page 2) by [V. Ye. Beloshevskiy], the Electronics Department Chief of the Belorussian Railroad Computer Center in which the unreliability of the 565RU1 ICs are described, and ways to add redundancy to the (YeS1035) computing systems.

Top image: 565RU1 die manufactured in 1981.