From Wikipedia, the free encyclopedia Motorola 56000
Motorola 56000
(ADCs) and digital-to-analog converters (DACs) rarely ex-
ceeded 20 bits. One example is ADSL applications, where
filters typically require 20 bits of accuracy.[citation needed]
The leftmost four bits are considered ample headroom
for calculations.
Applications and variants
In most designs the 56000 is dedicated to one single task,
because digital signal processing using special hardware
is mostly real-time and does not allow any interruption.
For somewhat more mildly demanding tasks which are
Motorola XSP56001
not time-critical, or more of a simple "if-then" type, de-
signers normally use a separate CPU or MCU.
56K)
The Motorola DSP56000 (aka 56K is a family of digital
The addition of SIMD instructions to most desktop
signal processor (DSP) chips produced by Motorola Semi-
computer CPUs have meant that dedicated DSP chips like
conductor (now known as Freescale Semiconductor)
the 56000 have partly retreated from some application
starting in the 1980s and is still being produced in more
fields, but they continue to be used widely in communi-
advanced models in the 2000s. The 56k series was quite
cations and other professional uses. To this end the 56800
popular for a time in a number of computers, including
series added a complete MCU which created a single-chip
the NeXT, Atari Falcon, and SGI Indigo workstations. Up-
"DSPcontroller" solution, while the opposite occurred in
graded 56k versions are still used today in audio gear,
the 68456—a 68000 with a 56000 on it.
radars, communications devices (like mobile phones) and
A quite prevalent recent model of the 56000 is the 3rd
various other embedded DSP applications. The 56000 was
generation 563xx family, which features several models
also used as the basis for the updated 96000, which was
with special applications hardware built-in, like PCI in-
not commercially successful.
terface logic, CRC processors, or audio companders.
Technical description External links
The DSP56000 uses fixed-point arithmetic, with 24-bit
• Freescale Digital Signal Processors
program words and 24-bit data words. It includes two
• A56 freeware assembler for the 56000 architecture
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); other- List of Motorola digital signal processors (DSPs)
wise, the accumulators are similar to the other 24/48-bit Motorola DSP560XX (24-bit) | Motorola DSP566XX
registers. Being a Harvard architecture processor, the (16-bit) | Motorola DSP563XX (16/24-bit) | DSP568XX
56k has two separate memory spaces+buses (and on-chip (DSPcontroller) | Motorola DSP96XXX (32-bit)
memory banks in some of the models): a program memo-
ry space/bus and a data memory space/bus.
24 bits were selected as the basic word length because
it gave the system a reasonable number range and preci-
sion for processing audio (sound), the 56000’s main con-
cern. 24 bits correspond to a large 144dB dynamic range,
sufficient in the 1980s when analog-to-digital converters
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Categories:
• Freescale Semiconductor
• Digital signal processors
• Motorola products
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From Wikipedia, the free encyclopedia Motorola 56000
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