DSP (Nintendo)

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The DSP-1 (also the DSP-1A, DSP-1B), DSP-2, DSP-3^[1], and DSP-4^[2] are digital signal processors used in some Super Nintendo Entertainment System cartridges. They have the same core architecture as the NEC uPD77C25 DSP, the only differences between them being Nintendo's custom internal ROMs. While digital signal processors are commonly used as real-time signal processors (in speech synthesis for example), the SNES DSP chips are simply coprocessors with specialized instruction sets.

DSP-1: The DSP-1 is the most varied and widely-used of the SNES DSPs, appearing in over 15 separate titles. It is used as a math coprocessor in games such as Super Mario Kart and Pilotwings that require more advanced Mode 7 scaling and rotation. It also provides fast support for the floating point and trigonometric calculations needed by 3D math algorithms. The later DSP-1A and DSP-1B serve the same purpose as the DSP-1, however, several bugs were corrected in these later chips.

DSP-2: The DSP-2 can only be found in the SNES port of Dungeon Master. Its primary purpose is to convert Atari ST bitmap image data into the SNES bitplane format. It also provides dynamic scaling capability and transparency effects.

DSP-3: An assistant chip used only in one Japanese game for the Super Famicom titled SD Gundam GX. Although this chip does handle graphics decompression and bitplane conversion, a large portion of memory inside this chip is dedicated to rendering a very complicated title screen, leading one to the likely conclusion that its inclusion was more intended to prevent the game from being easily pirated.

DSP-4: A DSP used in only one game cartridge, Top Gear 3000. It primarily helped out with drawing the race track, especially during the times that the track branched into multiple paths, which was a unique feature of this type of game at the time.

[edit] List of games that use a DSP series chip

It is difficult to tell whether a cartridge contains a particular version of the DSP-1/1A/1B series unless it is internally inspected. This is because various versions were printed with the updated DSP-1A/1B.