Difference between revisions of "Motorola MC68000"
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[[Image:mc68000.jpg|thumb|200px|right|MC68000 from a Macintosh SE]] | [[Image:mc68000.jpg|thumb|200px|right|MC68000 from a Macintosh SE]] | ||
| − | The '''Motorola MC68000''' was the first member of the [[Motorola M68000 Family]] of [[VLSI]] [[microprocessor]]s. Although it was described by | + | The '''Motorola MC68000''' was the first member of the [[Motorola M68000 Family]] of [[VLSI]] [[microprocessor]]s. Although it was described by Motorola as a "16-bit microprocessor", it is generally considered to be a 32-bit [[architecture]]; it is probably more correct to describe it as a 16-bit '''''implementation''''' of a 32-bit architecture. |
A major failing of the MC68000 was that it could not support [[virtual memory]]; not enough internal state was saved when a [[page fault]] occurred. Several computer makers worked around this by including two separate MC68000 chips; when a fault occurred, the first CPU was 'frozen', and a second fixed up the fault, then re-started the 'main' CPU. This issue was fixed with the successor chip, the [[MC68010]]. | A major failing of the MC68000 was that it could not support [[virtual memory]]; not enough internal state was saved when a [[page fault]] occurred. Several computer makers worked around this by including two separate MC68000 chips; when a fault occurred, the first CPU was 'frozen', and a second fixed up the fault, then re-started the 'main' CPU. This issue was fixed with the successor chip, the [[MC68010]]. | ||
Revision as of 15:38, 11 February 2023
| MC68000 | |
| Family: | Motorola M68000 Family |
|---|---|
| Architecture: | 32-bit |
| Manufacturer: | Motorola |
| Year Introduced: | 1979 |
| Address bus: | 23-bit (16-bit word address) |
| Data bus: | 16-bit |
| Number of registers: | 15 general 32-bit registers (8 data, 7 address) |
| Clock Speed: | 4 MHz - 16.67 MHz |
The Motorola MC68000 was the first member of the Motorola M68000 Family of VLSI microprocessors. Although it was described by Motorola as a "16-bit microprocessor", it is generally considered to be a 32-bit architecture; it is probably more correct to describe it as a 16-bit implementation of a 32-bit architecture.
A major failing of the MC68000 was that it could not support virtual memory; not enough internal state was saved when a page fault occurred. Several computer makers worked around this by including two separate MC68000 chips; when a fault occurred, the first CPU was 'frozen', and a second fixed up the fault, then re-started the 'main' CPU. This issue was fixed with the successor chip, the MC68010.
