Motorola 56000

The Motorola DSP56000 (aka 56K) is a family of digital signal processor (DSP) chips produced by Motorola Semiconductor (now known as Freescale Semiconductor) starting in 1986 and is still being produced in more advanced models in the 2000s. The 56k series was quite popular for a time in a number of computers, including the NeXT, Atari Falcon (56001), and SGI Indigo workstations. Upgraded 56k versions are still used today in audio gear, radars, communications devices (like mobile phones) and various other embedded DSP applications. The 56000 was also used as the basis for the updated 96000, which was not commercially successful.

Technical description

The DSP56000 uses fixed-point arithmetic, with 24-bit program words and 24-bit data words. It includes two 24-bit registers, which can also be referred to as a single 48-bit register. It also includes two 56-bit accumulators, each with an 8-bit "extension" (aka headroom); otherwise, the accumulators are similar to the other 24/48-bit registers. Being a Modified Harvard architecture processor, the 56k has three memory spaces+buses (and on-chip memory banks in some of the models): a program memory space/bus and two data memory space/bus.