Creating a MIDI synth from a Commodore SID

The Commodore SID was the audio chip in the venerable Commodore 64 and in the 30 years since release has attained classic status and become one of the best ways to get your chiptune on. Designed by famous synthesizer designer [Bob Yannes], it was only a matter of time before we saw a real, homebrew MIDI synth based on the Commodore SID.

Because real SID chips are rare as hen’s teeth nowadays, [Jeff Ledger] built his SID synth around an emulated system running on a Pocket Mini Computer. This very cool microcontroller platform runs on the Parallax Propeller. An emulated SID runs in one of the Propeller’s 8 cores, with the remaining cores kept open for reading MIDI notes and displaying info on a display.

The hardware portion of this build is amazingly simple; just an optoisolater, a few resistors, and a diode connect a MIDI keyboard to the Pocket Mini Computer. The buttons and dials on [Jeff]’s MIDI keyboard control the waveforms, filters, and envelope controls. A very neat setup if we do say so ourselves, and just perfect if you’re needing more chiptunes in your life.

You can check out [Jeff]’s video after the break.

Continue reading “Creating a MIDI synth from a Commodore SID”

Propeller turned into chiptune player with a software SID

If there wasn’t reason enough to love the Parallax Propeller, now you can listen to chiptunes with your own pocket SID audio player.

This chiptune audio player uses the very unusual and very cool eight-core Parallax Propeller microcontroller. After soldering a few caps and resistors to a Propeller dev board to allow for audio out, the only thing necessary to play SID music files is a bit of code and an SD card breakout.

The key piece of code for this build would be the SIDcog object written by [Johannes Ahlebrand] this piece of code turns one of the eight cores in the Propeller into a virtual version of the classic Commodore 64 sound chip.

Since the SIDcog object only takes up one core on the eight core Propeller, it could be possible to turn this SID player into an all-inclusive chiptune audio source; the addition of an Atari POKEY or FM synthesis cog would allow for just about any conceivable chiptune sound to be carried around in a pocket.

No Hackaday post about chiptunes or SIDs would be complete without an audio demo, so you can check out the Propeller-powered SID after the break.

Continue reading “Propeller turned into chiptune player with a software SID”

Making chiptunes with 32 bytes of RAM

Ah, chiptunes. One of the few remaining human endeavours where less RAM, less storage space, and fewer capabilities are actually considered an improvement. [dop3joe] over at the Stuttgart hackerspace Shackspace sent in a tiny chiptune playing circuit using the most bare-bones hardware we’ve ever seen.

The Noiseplug, as [dop3joe] calls it, is based on a very, very small 6 pin ATtiny9. With 1 kB of Flash memory and only 32 bytes of RAM [dop3joe] was able to create a small device inside an RCA jack that plays chiptunes whenever it is powered by a battery.

If you’d like to make your own noise plug, [dop3j0e] put all the code up in his Git. There are two relevant pieces of software for this build: a Windows app to create the chiptunes, and the ATtiny9 firmware itself. Of course to program the tiny, you’ll have to deal with the Atmel TPI, so here’s the application note (PDF).

Oh, [dop3joe] won third place at the Evoke demoscene party last weekend with the Noiseplug. Awesome.

Chiptune player uses preprocessed .MOD files

[Kayvon] just finished building this chiptune player based on a PIC microcontroller. The hardware really couldn’t be any simpler. He chose to use a PIC18F2685 just because it’s big enough to store the music files directly and it let him get away with not using an external EEPROM for that purpose. The output pins feed a Digital to Analog Convert (DAC) chip, which in turn outputs analog audio to an LM386 OpAmp. The white trimpot sandwiched between the chips controls the volume.

The real work on this project went into coding a program which translates .MOD files into something the PIC will be able to play. Because of the memory limits of the chip it is unable to directly use all of the instrument samples from these files. [Kayvon] wrote a program with a nice GUI that lets him load in his music and page through each instrument to fine-tune how they are being re-encoded. The audio track from the video after the break doesn’t do the project justice, but you will get a nice look at the hardware and software.

Continue reading “Chiptune player uses preprocessed .MOD files”

Putting an Atari POKEY in your pocket

The Atari POKEY served as the main I/O chip on the venerable Atari 400/800 and XL/XE 8-bit computers. While a chip designed to get voltages from game paddles and scanning a matrix of keyboard switches wouldn’t normally be remembered 30 years later, the POKEY had another function: generating very, very distinctive music and sound effects for those old Atari games. [Markus Gritsch] wanted a portable version of the POKEY, so he emulated one on a modern microcontroller. Now he’s able to take those old Atari chiptunes where ever he goes.

The build uses the Another Slight Atari Player by emulating a 6502 and POKEY chip inside [Markus]’ PIC32MX-based microcontroller. There’s not much physical hardware [Markus] had to deal with – the board is built on a QFP proto board [Markus] picked up with a few buttons and a jack added for some simple I/O.

This isn’t [Markus]’s first attempt at portabalizing chiptunes – last year, we saw a truly awesome portable SID player that used the same PIC32 microcontroller and an emulated 6502. Between the Atari SAP Music Archive and the High Voltage SID Collection, [Markus] has more than enough chiptunes for days of listening pleasure.

Putting every chiptune ever in an FPGA

Finally one device combines the power of the Commodore 64 SID, Atari ST YM2149, and Amiga MOD audio into one awesome box. It’s called the RetroCade Synth, and there’s a Kickstarter that is perfect for starting your chiptune composing journey.

[Jack]’s RetroCade synth is connects directly to the Papilio One 500k FPGA. All the classic chiptune ICs can be emulated in this FPGA including the Commodore 64 SID chip, and an Amiga MOD player. Being a follow-up to [Jack]’s previous FPGA YM2149 project, he also threw that chip into the project for good measure. While the RetroCade doesn’t ship with every old chiptune IC – there isn’t support for NES, Atari, GameBoy, or SN76489-based chiptunes yet – that is something [Jack] will add once the Kickstarter is completed.

After the break you can see [Jack] jamming out on his RetroCade project playing a YM2149, SID, and Amiga MOD sounds simultaneously. For $100, it’s comparable to the venerable MIDIbox SID, but also allows anyone to play whatever genre of chiptunes they desire.

Continue reading “Putting every chiptune ever in an FPGA”

Building an Arduino Chiptunes project inside an FPGA

From time to time we find ourselves in the mood for some Chiptunes. You know, the music that accompanied all of the best 8-bit console games? These days there are a lot of projects that use the audio chips of yore to recreate the sounds, but you’re always faced with the issue of sourcing those parts. [Jack Gassett] took some inspiration from one of those projects, but solved the rare hardware dilemma by building his own Chiptunes MIDI device in an FPGA.

He saw one of our features on an Arduino controlled YM2149 programmable sound generator. He realized that you can already find FPGA libraries out there that mimic this sound generation hardware, and he’s already done extensive work with an Arduino soft processor. Why not combine the two?

He’s using a Papilio FPGA with a wing that includes a MIDI connector and audio-out jack. As you can hear in the clip after the break this sounds just like the real thing. And he’s got plans to roll as many different types of sound generating chips into the mix as possible. You know, one FPGA synth to rule them all.

Continue reading “Building an Arduino Chiptunes project inside an FPGA”