right|thumb|180px|motorola xsp56001 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 motorola dsp56000 digital signal processor ieee24-bit. digital signal processor. familyfractional and integer arithmetic using the dsp56000 familyprogrammable dsp architecturesmotorola dsp56000 family optimizing c compiler user's manual the 56k series was quite popular for a time in a number of computers, including the next, atari falcon (56001),atariforge.org - atari falcon030 schematic rev a, 1992-06-28 and sgi indigo workstations. upgraded 56k versions are still used  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. 24 bits were selected as the basic word length because it gave the system a reasonable number range and precision for processing audio (sound), the 56000's main concern. 24 bits correspond to a large  dynamic range, sufficient in the 1980s when analog-to-digital converters (adcs) and digital-to-analog converters (dacs) rarely exceeded 20 bits. one example is adsl applications, where filters typically require 20 bits of accuracy. the leftmost four bits are considered ample headroom for calculations. 
Digital_signal_processors Freescale_Semiconductor Motorola_products