Smooth Animations, Slick Bar Graphs, But No Custom Characters On This 16×2 OLED

April 27, 2023 by Dan Maloney 7 Comments

Sometimes, finding new ways to use old hardware requires awesome feats of reverse engineering, software sleight of hand, and a healthy dose of good fortune. Other times, though, it’s just as simple as reading the data sheet and paying attention to details.

Not that we’re knocking [upir]’s accomplishment with these tricked-out 16×2 OLED displays. Far from it, in fact — the smoothly animated bar graph displays alphanumerics look fantastic. What’s cool about this is that he accomplished all this without resorting to custom characters. We’ve seen him use this approach before; this time around, the hack involves carefully shopping for a 16×2 OLED display with the right driver chip — a US2066 chip. You’ll still need a few tricks to get things working, like extra pull-up resistors to get the I2C display talking to an Arduino, plus a little luck that you got a display with the right character ROM.

Once all that is taken care of, getting the display to do what you want is mainly a matter of coding. In the video below, [upir] does a great job of walking through the finer points, and the results look great. The bar graphs in particular look fantastic, with silky-smooth animations.

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Creating A Game Boy ROM From Pictures

March 23, 2023 by Bryan Cockfield 22 Comments

There are very few legal ways of obtaining ROM files for video games, and Nintendo’s lawyers are extremely keen on at least reminding you of the fact that you need to own the game cart before obtaining the ROM. With cart in hand, though, most will grab a cart reader to download the game files. While this is a tried-and-true method, for GameBoy games this extra piece of hardware isn’t strictly required. [Travis Goodspeed] is here to show us a method of obtaining ROM files from photographs of the game itself.

Bits can be manually edited to fix detection errors.

Of course, the chips inside the game cart will need to be decapped in order to obtain the pictures, and the pictures will need to be of high quality in order to grab the information. [Travis] is more than capable of this task in his home lab, but some work is still required after this step.

The individual bits in the Game Boy cartridges are created by metal vias on the chip, which are extremely small, but still visible under a microscope. He also has a CAD program that he developed to take this visual information and extract the data from it, which creates a ROM file that’s just as good as any obtained with a cart reader.

This might end up being slightly more work especially if you have to decap the chips and take the photographs yourself, but it’s nonetheless a clever way of obtaining ROM files due to this quirk of Game Boy technology. Encoding data into physical hardware like this is also an excellent way of ensuring that it doesn’t degrade over time. Here are some other methods for long-term data storage.

Pokemon ROM Hacks Brought To The Real World

February 27, 2023 by Bryan Cockfield 4 Comments

If you were a kid anywhere in the last 30 years, it was nearly impossible to avoid at least some exposure to the Pokemon franchise. Whether that’s through games like Red and Blue to Scarlet and Violet, the brief summer everyone played Pokemon Go, or to other media such as the trading card game or anime, it seems to have transcended generations and cultures fairly thoroughly. And, if you’ve consumed all there is of official Pokemon video gaming, you may be surprised to know there are a number of slightly modified games floating around out there that can be translated onto game carts just like their official counterparts.

[imablisy] has played a lot of these ROM hack games but always within something like a virtual console or emulator, so he wanted something physical which would work on original hardware of the era. For this he’s making physical copies of Flora Sky and Vega, which are based on Pokemon Emerald and Fire Red originally for the Game Boy Advance. To get the cart he found a bunch of Mother 3 cartridges to use as the donor. From there he backed up his Emerald and Fire Red cartridges, modified the ROMs with the modifications, and then sent those new ROMs to overwrite the data on the Mother 3 cartridges.

A playable cartridge is only half of the build, though. He wants these to look and feel like real Pokemon games, so he added a color-appropriate translucent case and also printed custom holographic labels for each. It might seem straightforward, but from the style of [imablisy]’s video it’s clear he is very familiar with processes like these, from the artwork all the way to the hardware and software side. We’re also pleased no classic hardware was damaged during this build, much like this version of Doom on an NES cart which used a common game for the donor to upset the least number of collectors.

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Squeezing A Minimalist 6502 Retrocomputer Onto A Single Breadboard

January 4, 2023 by Dan Maloney 10 Comments

Over the years, and especially lately, we’ve seen tons of single-board retrocomputer builds. That’s fine with us — the more, the merrier. But they all start to run together a bit, with little to distinguish between them. Not so this about-as-compact-as-possible 6502 computer that fits on a single breadboard.

Now, when you do the math, it seems like there’s no way that [Anders Nielsen] would have been able to fit even a minimal chipset onto a standard solderless breadboard. The 40-pin 6502 alone takes up nearly two-thirds of the connections available; add in equally large but necessary chips like the 6522 interface adapter, ROM and RAM chips, and some support ICs, and one breadboard isn’t going to cut it. Luckily, some frugal engineers at MOS back in the 70s came up with the 6507, a variant on the 6502 in a 28-pin DIP. The other key to this build is the 6532 RAM-I/O-timer chip or RIOT, which puts a tiny amount of RAM and some IO lines on a single 40-pin DIP. Along with a 28-pin ROM, a 14-pin hex inverter, and a little crystal oscillator, the entire chipset just barely fits on a single breadboard.

But what can this minimalist 6502 actually do? As you can see in the video below, anything a 555 timer can do, and maybe a little bit more. That’s not a dig, of course — [Anders] actually calls out his initial blinkenlight application as a little more than a glorified 555, and actually comes up with a marginally more complex application just to prove the point. The interesting part here is dealing with the constraints imposed by the limited resources available on this machine.

We’re looking forward to whatever comes next for this clever build. It’s hard to see how some of the plans [Anders] has for it will still fit on a single breadboard, though — these things tend to spread out as they go.

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Bringing Up An Old Motherboard Is A Delicate Process

November 12, 2022 by Dan Maloney 12 Comments

If you were around for the early days of the personal computer revolution, you’ll no doubt recall the excitement every time IBM announced a new version of its beige boxes. For a lot of us, the excitement was purely vicarious, for despite the “personal” moniker, mere mortals could rarely afford a branded IBM machine. But it was still cool to keep track of the latest releases, and dream of the days when cheap clones would make it possible to play.

[Anders Nielsen]’s recent find of an original IBM Model 5160 motherboard sort of echoes that long-ago excitement, but in a different way. This board, from a PC XT built in 1984, was in unknown condition upon arrival, so [Anders] set about a careful process to try to bring the board back to life. A quick visual inspection leaves one with a sense of both how much things have changed, and how much they’ve stayed the same. Aside from the big 40-pin DIP 8088 CPU and the BIOS ROMs, the board is almost completely populated with discrete logic chips, but at the same time, the basic footprint of a motherboard has changed very little.

The bring-up process in the video below includes checks of all the power rails for shorts, which ended up being a good call — drat those tantalums. After fixing that issue, [Anders] had a bit of trouble getting the board to POST, and eventually resorted to dumping the BIOS ROMs and inspecting the contents. One of the chips had picked up a case of the scramblies at some point, which was easy enough to fix thanks to images of the 5160 ROMs available online. We thought the trick of using a 64k ROM and just writing the BIOS image twice was pretty clever.

In the end, the board came up, although without video or keyboard — that’s for another day. Can’t find your own PC XT motherboard to play with? Then maybe you can just build one.

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Taking Pokémon On A Walk

November 9, 2022 by Bryan Cockfield 7 Comments

Emulating old computers or video game systems isn’t always about recreating childhood nostalgia or playing classics on hardware that doesn’t exist anymore. A lot of the time it can be an excellent way to learn about the mechanics of programming a video game. Plenty of older titles have available source code that anyone can pour over and modify, and one of those is Pokémon Emerald. This was the first Pokémon game that [Inkbox] played, and he added a few modern features to it with this custom ROM file.

The first thing to add to this game was the ability to have one’s Pokémon follow their character around in the overworld map. This is common in later games, but wasn’t yet a feature when Emerald and Ruby first came out. [Inkbox] needed to import sprites from later games into the Emerald game file, convert their color palettes to match the game’s palette, and then get to work on the mechanics. After everything was finished, the Pokémon not only follow the player around the map but are animated, enter and exit their Pokéballs, and even jump off ledges in a believable, 32-bit way.

One of the great things about older games like these is that they’ve been around long enough to have source code or decompiled code available, they often have plenty of documentation, and the platforms they operate on are well-known by now as well. Pokémon Emerald is not alone in this regard; in fact, there is a huge Game Boy Advance homebrew scene that is not too difficult to get involved in.

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Swapped ROM Revives Ailing HP-48S Calculator

June 9, 2022 by Tom Nardi 10 Comments

Buying broken gear for cheap is time honored hacker tradition, and while we might not always be successful in reviving it, rarely do we come away empty handed. There’s always parts to salvage, and you can’t put a price on the knowledge to be gained when poking around inside an interesting piece of hardware. So we’re not surprised at all to hear that [Tomas Pavlovic] jumped at the chance to grab this faulty HP-48S calculator for a couple bucks.

Luckily for us, the story doesn’t end at the bottom of his parts bin. When he got the HP-48S back home, he immediately set out to see if it could be repaired. After changing out a few choice components and not seeing any result in the device’s behavior, he became suspicious that the problem may be with the firmware; specifically, the soldered-on chip that holds it.

After carefully lifting the NEC uPD23C2000GC from its resting place for the last 30 years or so, he wired up an adapter that let him connect the chip to his programmer so its contents could be dumped. Rather than trying to find another ROM chip, he decided to wire in a socket and found a re-writable SST39SF040 that could stand in as a replacement. Flashing a fresh copy of the firmware to the new socketed chip got the calculator up and running again, with the added bonus of allowing [Tomas] to pull the chip and flash a different firmware version should he care to experiment a bit.

Now, we know what you’re thinking. Where was the fix? What exactly brought this piece of 1990s gear back to life? That part, unfortunately, isn’t very clear. You’d think if the original ROM chip was somehow faulty, [Tomas] wouldn’t have been able to so easily pull a valid firmware image from it. That leaves us with some pretty mundane possibilities, such as a bad solder joint on the chip’s pins. If that was indeed the case, this fix could have been as simple as running a hot iron over the pins…but of course, where’s the fun in that?

Update: We heard back from [Tomas], and it turns out that when compared to a known good copy, the dumped firmware did have a few swapped bits. His theory is that the NEC chip is in some weird failure mode where the calculator wouldn’t run, but it was still functional enough to get most of the content off of it. What do you think? Let us know in the comments.