A Genesis Inspired Synthesizer That Has Nothing To Do With Phil Collins

January 25, 2019 by Lewin Day 11 Comments

Chiptune is a musical genre built upon the creation of music through the use of chip-based sound synthesizers, found in early game consoles. The Commodore 64’s venerable SID chip and the Game Boy Sound System are the by far the most popular on the scene. However, the Sega Genesis took a different path at the end of the videogame chipmusic era, packing a YM2612 FM synthesis chip to deliver fat basslines and searing solos. [Thea] has always been a fan of these electric 90s sounds, and thus decided to build the Genesynth.

The synth initially allowed only for playback of existing video game scores, but its capability has been expanded as [Thea] took the project from breadboard to protoboard to custom PCBs – with anime artwork, to boot. The synth uses a Teensy 3.5 as the brains, speaking USB to enable the synth to receive MIDI commands from music software. All parameters are exposed over the interface, and [Thea] has several videos showing the Genesynth under control from an Ableton Push.

The sound capabilities of the YM2612 are of an entirely different character to most chiptunes, by virtue of the FM synthesis engine. FM synthesis is a little less intuitive then classical additive synthesis, but we still see it crop up now and then.

Putting The Sega Teradrive Into Overdrive

October 9, 2018 by Drew Littrell 25 Comments

During the 80s and 90s it seemed like Japan got all the good stuff when it came to videogames. In the US there were consoles called the NES, the TurboGrafx-16, and the Genesis. While in Japan they had cooler names like: the Famicom, the PC Engine, and the Mega Drive. The latter was incorporated into a plethora of different form factors, including the little known IBM PC/Mega Drive combo known as the Sega Teradrive. Finding a rare Japanese 1990s PC stateside is a feat in and of itself, and thanks to an electronics hobbyist named [Ronnie] there is at least one Teradrive out there still running strong thanks to an upgraded CPU mod.

In theory, the Sega Teradrive was a dream-machine; combining the utility of an IBM PC with the fun of a Sega Mega Drive. The dual functionality extended to the video modes where both VGA and composite video were supported. However, the reality was that the final design was less than desirable. The Teradrive shipped in 1991 with an Intel 80286, 16-bit processor which was already two processor generations behind at the time. The meager 10Mhz clock speed was on the lower end of the performance spectrum which meant that many DOS titles ran poorly…or not at all.

Not satisfied with those specs, [Ronnie] modded his Teradrive with an adapter board containing an Intel 80486 processor clocked at 66Mhz. The upgrade, accompanied with a complete re-cap of the motherboard, brings the IBM PC to 486DX status. This opened up a few new possibilities including the Thundercats Demo in the video below:

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We Got Your Sega Chiptunes Right Here

October 4, 2018 by Brian Benchoff 14 Comments

Chiptunes are cool, but when you get into it, you realize you’re mostly dealing with Commodore SID tunes, Atari POKEY tracks for the cool kids, bleeps and bloops from a Game Boy, and maybe some NES tracks thrown in for good measure. There’s another option out there – the sound chip in the Sega Genesis. This thing could do drums, man, and [Aidan Lawrence] built the perfect player for the tuneful silicon tucked inside the classic 16-bit console.

[Aidan] had previously built a tiny little music player based on the YM3812 chip, the Yamaha chip found in SoundBlaster and Adlib sound cards. The chip inside the Sega Genesis, the Yamaha YM2612, is a bit different. The killer feature of this chip, PCM waveforms, aren’t stored as simple, small bits of code. These are massive blobs of binary data sent to the chip’s DAC. The SEGGGGAAAA intro of Sonic the Hedgehog, for example, used an eighth of the the cartridge space. You’re not going to build a Sega chiptune player with a tiny little microcontroller and 20kB of RAM.

The solution came in the form of an external SPI RAM device. The 23LC1024 is a full 1 Megabit in size, and since it’s SPI, it’s more than fast enough to keep up with the sample speed. The rest of the circuit including the mixer, preamp and power amp are based on the Genesis’ actual schematics, with an SD card and OLED thrown in for good measure. How does it sound? There’s a great video below the break and yes, the soundtrack from Sonic 3 sounds just as good as it did twenty years ago.

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Can You Visualise A Sega Cart From 2017?

August 31, 2017 by Lewin Day 13 Comments

The Sega Genesis, or Mega Drive if you’re not from North America, isn’t exactly this summer’s hottest new console, but it still has a huge following 29 years after launch. Fans range from retro Sonic enthusiasts to hardcore chiptune composers, and this year, Catskull Electronics is releasing a Genesis compilation album on a cartridge with a rather special feature.

The cartridge sports an 8×8 LED matrix, which acts as a visualiser for the audio coming out of the console. They’re controlled with a combination of data and address lines with some buffers and 74-series glue logic to make it all work together. Special attention was paid to make sure the LED matrix doesn’t just respond to all activity on the bus, though it would perhaps be cool to see some blinkenlights on a 90s console one day.

Each row of LEDs is attached to an address line, and each column to a data line. It’s a fairly basic multiplexing setup which sees each LED only actually lit for a fraction of a second, but sweeping the display at speed creates a lasting display. The image data is stored as an 8×8 sprite in the system RAM, and updated with the sound level of each channel from the Genesis’s audio subsystem.

The team are looking to release the ROM code in future to inspire copycat designs, which has the potential to spawn even more Genesis cart releases in future. We look forward to seeing what else the community comes up with. And if you’re a die-hard Genesis fan, there are other ways to listen to those classic tunes too.

Sega Genesis Chiptunes Player Uses Original Chips

February 17, 2017 by Jenny List 16 Comments

If you were a child of the late 1980s or early 1990s, the chances are you’ll be in either the Super Nintendo or the Sega Genesis/Mega Drive camp. Other 16-bit games consoles existed, but these were the ones that mattered! The extra power of the Nintendo’s souped-up 16-bit 6502 derivative or the Sega’s 68000 delivered a gaming experience that, while it might not have been quite what you’d have found in arcades of the day, was at least close enough that you could pretend it was.

The distinctive sound of consoles from that era has gained a significant following in the chiptunes community, with an active scene composing fresh pieces, and creating projects working with them. One such project is [jarek319]’s Sega Genesis native hardware chiptune synthesiser, in which music stored as VGM files on a MicroSD card are parsed by an ATSAMD21G18 processor and sent to a YM2612 and an SN76489 as you’d have found in the original console. The audio output matches the original circuit to replicate the classic sound as closely as possible, and there is even some talk about adding MIDI functionality for this hardware.

The software is provided, though he admits there is still a little way to go on some functions. The MIDI support is not yet present, though he’s prepared to work on it if there was enough interest. You really should hare this in action, there is a video which we’ve placed below the break. Continue reading “Sega Genesis Chiptunes Player Uses Original Chips” →

3 Billion Devices And A Sega Genesis Run Java

November 23, 2015 by Brian Benchoff 24 Comments

A few years ago, [Mike]’s friend gave him an old Sega Genesis with the very cool and somewhat rare SegaCD drive attached. The SegaCD gave him an idea – while it’s not easy to burn a cartridge and play homebrew games on a real Genesis console, everyone has a CD burner somewhere. [Mike] began writing his demo and then realized adding Java would be easy on the 68000. The result is Java on three billion devices and a Sega Genesis.

This project is built around Java Grinder a Java byte code compiler that will compile classes, factories, and all the horrible Java design.design.pattern.pattern.patterns() into assembly language. Already, there are a lot of platforms supported by Java Grinder, including the Commodore 64, the TI99, and thanks to some work from [Joe Davisson], the Apple IIgs

With a byte code compiler, an assembler, and an API for the Sega-specific hardware, [Mike] set about building his demo. Since this was a Sega, it needed the ‘SEGA’ sound at the start. [Mike] ended up recording his voice saying ‘JAVA!’ This plays through the Z80 on the Genesis.

The complete demo – viewable in its emulated format below – has everything you would expect from a proper demo. Starfields, dancing sprites, and even a Mandelbrot pattern make it into the three-minute long demo.

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[lovablechevy] Transforms A Nomad Into The HandyGen

January 12, 2015 by Theodora Fabio 1 Comment

[lovablechevy], aka the Queen of Bondo, has added another member to her Mushroom family of custom portable consoles. This time, it’s the HandyGen, an improved Sega Nomad. As an owner of the latter, we can attest that the Nomad had limitations, including its unwieldy size and shape, and its godawful battery life. As part of a build-off contest over at the Bacman forums , [lovablechevy] took apart a half-working Nomad and trimmed its board to fit into a smaller case of her own design, while retaining features such as the A/V out, headphone jack, and Player 2 controller port. She also bumped up the size of the screen, swapping in a new 4″ LCD and its corresponding controller board. The best improvement was increasing the battery life considerably; HandyGen uses 2 LiPo batteries lasting 7 hours instead of the Nomad needing 6AA’s that barely lasted two. HandyGen’s battery life is roughly double that of the GeneBoy, an earlier portable Genesis mod we’ve featured before.

[lovablechevy] always does a great job with her portables, from the Nintenduo to the HandyNES. Being avid PS fans, we also award her bonus points for testing out the HandyGen with Phantasy Star 4. Check out her video of the HandyGen after the break.

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