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SMPS

From Sega Retro

Sample Music Playback System (SMPS) is the common name of a family of audio playback engines (or "drivers") and storage formats used by various Sega consoles (including the Sega Mega Drive, Sega Mega-CD, Sega 32X, Sega Master System and Sega Game Gear). "SMPS" is thought to be a colloquial term - there is no evidience to suggest this was the naming scheme of any official drivers, but is the most widely accepted name for the system.

Like other sound drivers, SMPS was designed as a means of processing audio information, allowing a console's CPU to communicate with sound chips on the board and create audible sound (i.e. "driving" the sound). It is usually associated with first-party Japanese Mega Drive games (where it was most predominantly used) - analogous to Sega of America's use of the GEMS driver, and began appearing in games from the late 1980s until the aforementioned consoles bowed out of the market.

By sharing drivers between games, developers could create tools to quickly produce audio, and it allows for music and sound effects to be more easily ported between games.

Variants

Mega Drive and 32X

Mega Drive (and by extension, 32X) developers had a choice of which processor to run SMPS on; the 16-bit 68000, or the 8-bit Z80. The driver variants are known as SMPS 68000 and SMPS Z80 respectively.

Some developers, such as Treasure, chose to modify the driver, effectively making their own variants. Individual games such as Ristar also have their own modified drivers.

Games which use SMPS 68000

Mega Drive
32X

Games which use SMPS Z80

Mega Drive
32X

Mega-CD

SMPS-PCM is variant of SMPS designed to work on the Mega-CD's second 68000 processor, giving it access to the system's RF5C164 PCM chip.

Master System and Game Gear

SMPS drivers designed to work on the Z80 processors of the Master System and Game Gear were also produced. These tap into the two consoles' SN76489 chip.

Technical details

Tools

External links

References