Motorola MC68000: Difference between revisions
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| family = [[Motorola M68000 Family]] | | family = [[Motorola M68000 Family]] | ||
| architecture = 32-bit | | architecture = 32-bit | ||
| address bus = | | address bus = 23-bit (16-bit word address) | ||
| data bus = 16-bit | | data bus = 16-bit | ||
| year introduced = 1979 | | year introduced = 1979 | ||
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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 Motorala as a "16-bit microprocessor", it is generally considered to be a 32-bit | The '''Motorola MC68000''' was the first member of the [[Motorola M68000 Family]] of [[VLSI]] [[microprocessor]]s. Although it was described by Motorala 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 fault occurred. Several computer makers worked around this by including two separate MC68000 chips; when a | 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 13:07, 24 January 2018
| 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 Motorala 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.
