Information About68k |
| CATEGORIES ABOUT 68K | |
| 68k microprocessors | |
| central processing unit | |
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FAMILY MEMBERS
MAIN USES The 68k line of processors has been used in a variety of systems, from modern high-end Texas Instruments calculators (the TI-89 , TI-92 , and Voyage 200 lines) to older members of the Palm Pilot series, and even Radiation Hardened versions in the critical control systems of the Space Shuttle . However, they became most well-known as the processors powering Desktop Computers such as the Apple Macintosh , the Commodore Amiga , the Atari ST , and several others. The 68k was also the processor of choice in the 1980s for Unix Workstation s and Servers from companies such as Sun Microsystems , NeXT and SGI . Today, these systems are either end-of-line (in the case of the Atari), or are using different processors (as is the case for Amiga, Macintosh, Sun, and SGI). Since these platforms are now more than a decade old, their original manufacturers are unlikely to support an operating system for this hardware or are even out of business. However, the Linux , NetBSD and OpenBSD operating systems still include support for 68k processors. The 68k processors were also used in the Sega Mega Drive/Sega Genesis and SNK Neo Geo consoles as the main CPU. Other consoles such as the Sega Saturn used the 68k for audio processing and other I/O tasks, while the Atari Jaguar included a 68000 which was intended for basic system control and input processing, but due to the Jaguar's unusual assortment of heterogenous processors was also frequently used for running game logic. Microcontroller s derived from the 68k family have been used in a huge variety of applications. For example, CPU32 and ColdFire microcontrollers have been manufactured in the millions as automotive engine controllers. ARCHITECTURE People who are familiar with the PDP-11 or VAX usually feel comfortable with the 68000. With the exception of the split of general purpose registers into specialized data and address registers, the 68000 architecture is in many ways a 32-bit PDP-11. The 68k Instruction Set can be divided in the following broad categories:
68050 AND 68070 Note that there is no 68050; this is because the design that was destined to be the 68050 was eventually released as a version of the 68040 . There is also no revision of the 68060 , as Motorola was in the process of shifting away from the 68k and 88k processor lines into its new PowerPC business, so the 68070 was never developed. Had it been, it would have been a revised 68060. Motorola mainly used even numbers for major revisions to the CPU core such as 68000, 68020, 68040 and 68060. The 68010 vas a revised version of the 68000 with minor modifications to the core, and likewise the 68030 was a revised 68020 with some more powerful features, none of them significant enough to classify as a major upgrade to the ''core''. There was a CPU with the 68070 designation, which was a microcontroller version of the 16/32-bit 68000. This 68070 was used as the main CPU in the Philips CD-i . This CPU was, however, produced by Philips and not officially part of Motorola's 680x0 lineup. LAST GENERATION The 4th generation 68060 shared most of the features of the Intel P5 architecture. Had Motorola decided to continue the 680x0 series, the next processor (68080) would likely have resembled Intel's P6 architecture. OTHER VARIANTS After the mainline 68k processors' demise, the 68k family has been used to some extent in Microcontroller /embedded microprocessor versions. These chips include the ones listed under "other" above, i.e. the CPU32 (aka 68330 ), the ColdFire , the QUICC and the DragonBall . COMPETITORS Desktop During the 80s and early 90s, when the 68k was widely used in desktop computers, it mainly competed against Intel 's X86 architecture, which to this day remains the only architecture used in IBM Compatible PCs . Generation 1 68k CPUs primarily competed against the 16-bit 8086 / 8088 and 80286 . Generation 2 competed against the 80386 (the first 32-bit x86 processor), and generation 3 against the 80486 . The fourth generation competed with the original Pentium line, but it was not nearly as widely used as its predecessors, since much of the old 68k marketplace was either defunct or nearly-so (as was the case with Atari, Amiga and NeXT), or converting to newer architectures ( PowerPC for the Macintosh , SPARC for Sun , and MIPS for SGI ). Embedded There are literally dozens of processor architectures that are currently successful in Embedded Systems . Some are microcontrollers which are much simpler, smaller, and cheaper than the 68k, while others are relatively sophisticated and capable of running complex software. Embedded versions of the 68k often compete with processors derived from the PowerPC , ARM , MIPS , and SuperH architectures, among others. BIBLIOGRAPHY
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