Yamaha YM2413

Yamaha YM2413

The YM2413, aka OPLL, is a cost-reduced FM synthesis sound chip manufactured by Yamaha Corporation and based on their YM3812 (OPL2). To make the chip cheaper to manufacture, many of the internal registers were removed. The result of this is that the YM2413 can only play one user-defined instrument at a time; the other 15 instrument settings are hard-coded and cannot be altered by the user. There were other cost-cutting modifications: the number of waveforms was reduced to two, and the channels are not mixed using an adder; instead, the chip's DAC uses time-division multiplexing to play short segments of each channel in sequence, as also done in the YM2612.

List of YM2413 Applications

• The YM2413 was used on FM Sound Unit, an add-on for the Sega Mark III sold exclusively in Japan that improved the sound quality of all compatible games. The Japanese model of the Master System came with the YM2413 already integrated into the hardware.
• The YM2413 was used into arcade board design produced by SNK and Alpha Denshi in the late 1980s for a number of its games. Games using the design include Time Soldiers, Sky Soldiers, and Gang Wars.
• The YM2413 was used for Yamaha PSS-170 + PSS-270 in (1986)
• The YM2413 was used for the Yamaha PSS 140 in (1988)
• The YM2413 was used for Yamaha PSR-6 keyboard (1994),
• The YM2413 was also used by the MSX-Music sound expansion.

Variants and Clones

• Konami's VRC7 soundchip is a YM2413 derivative, used exclusively on the Family Computer game Lagrange Point.
• Yamaha YMF281 is another YM2413 derivative. It has the same pinout and register set, but a different sound bank.
• UMC U3567 is a 100% software compatible chip with a slightly different pinout, requiring a pin-to-pin adapter in order to be used on a YM2413 socket.
• UMC UM3567 is a 100% software compatible chip, has the same pinout of the U3567 but a slightly enhanced DAC output. It requires the same pin-to-pin adapter, but the different DAC output will also require two resistors to be removed from the motherboard.

External links

• MSX-Music
• d'Osvualdo, G. (2008), Luppes, E., Martin, C., Brychkov, E. (2013) "FM-Pak without SRAM". AGE Labs, 2013-12-29. Accessed on 2013-12-31.