Engineer and classic computing fanatic Jaroslav Sýkora, PhD, has constructed a substitute for the long-discontinued Yamaha YM2151 FM synthesis chip out of a Lattice Semiconductor iCE40UP5k field-programmable gate array (FPGA): AURA.
“[The] YM2151 was created by Yamaha in Nineteen Eighties, being utilized by Atari and Sega arcade programs beginning in 1984,” Sýkora writes of the chip’s storied historical past in a weblog submit dropped at our consideration by Adafruit. “As of 2023, this chip is maybe 1 / 4 of century out of manufacturing. The chip interfaces with then-standard 5V TTL logic, and the D/A [Digital to Analog] converter YM3012 even requires +/- 12V rails for its analog output.”
What do you do whenever you need a traditional Yamaha synth however it’s out of manufacturing? Emulate it in an FPGA. (📷: Jaroslav Sýkora)
Sýkora needed a contemporary and easily-obtainable equal to the YM2151 to be used within the X65, an open supply “final pc for everybody within the venerable 65-series of 8-bit and 16-bit CPUs” he’s within the technique of designing, and the same Commander X16. “I needed to make use of a Lattice iCE40 FPGA, to maintain in keeping with the remainder of my x65 design (each NORA [for system control] and VERA [for video generation] are iCE40 FPGAs).
“I name the FPGA system implementing the suitable FM-synthesis ‘AURA,’ from AUdio Retro Adapter. The emulation major half is finished by [the] IKAOPM undertaking, which is a Verilog synthesizable reproduction of the YM2151. AURA outputs the sound within the stereo 16-bit I2S format, which is transformed to the analog sign by the WM8524 D/A converter.”
The FPGA is software-compatible with the unique Yamaha half, however a lot simpler to implement in a contemporary system. (📷: Jaroslav Sýkora)
To show the system’s functionality, and its potential to run with out the ±12V provide required by Yahama’s unique implementation, Sýkora confirmed off a jukebox program: Calliope. “It may well play recordsdata within the ZSM format,” he explains, “[and] it helps output by means of the VERA PSG and YM2151 FM-synth.”
The complete undertaking write-up is offered on Sýkora’s weblog, whereas the supply code and machine {hardware} design recordsdata has been printed as a part of the X65 undertaking on GitHub beneath the permissive MIT license.
Fundamental article picture courtesy of Baz1521, Inventive Commons Attribution-Share Alike 3.0 Unported.
