carey@uiucdcs.CS.UIUC.EDU (12/17/85)
I have a data book published in 1983. The MC68008 is a 68000 with an
8-bit data bus (the address bus is 20 wide). The package is 48 pins,
.6" x 2.4". Otherwise it is the same as a 68000, it has the same
registers (same size), and same instruction set. They show specs for
8, 10, and 12.5 MHZ.
-John Carey
-- {ihnp4,convex,pur-ee}!uiucdcs!carey carey%uiuc@csnet-relay.arpa
carey@uiucdcs.CS.UIUC.EDUmarc@haddock.UUCP (12/17/85)
The 68008 is of the same family as all the rest of the 68xxx chips. The difference is that it is the 8-bit version. The table below should help a little: 68008 8-bit external 68000 16-bit external 68010 32-bit external 68020 32-bit external w/VMM
nigel@minster.UUCP (nigel) (12/18/85)
In article <35@gumby.UUCP> schaefer@gumby.UUCP writes: >Has anyone heard of the MC68008 processor? >If so does it have any improvements over the 68000? >respond to net.micro Yes - less legs.
tim@ism780c.UUCP (Tim Smith) (12/18/85)
> 68008 8-bit external > 68000 16-bit external > 68010 32-bit external > 68020 32-bit external w/VMM Actually: 68008 8-bit data bus, ?? bit address bus 68000 16-bit data bus, 24 bit address bus 68010 same as 68000 except bus error saves enough information to restart, vectors can be relocated, and more efficient microcode for some instructions 68012 same as 68010 except that address bus is 31 bits ( * ** a0 - a29 and a31 ). 68020 32 bit data and address buses, on-chip cache, new instructions, pipelined, more addressing modes, coprocessor interface. * Actually, there isn't an a0: the chip gives a word address, and there are two signals that tell if it is the upper byte, lower byte, or both, that is desired, but it is simpler to just pretend that there is an a0. ** No, I have no idea why they did it this way! -- Tim Smith sdcrdcf!ism780c!tim || ima!ism780!tim || ihnp4!cithep!tim
knnngt@ukma.UUCP (Alan Kennington) (12/19/85)
In article <35@gumby.UUCP> schaefer@gumby.UUCP writes: >Has anyone heard of the MC68008 processor? >If so does it have any improvements over the 68000? >respond to net.micro +++++++++I've heard that the lineeater no longer exists+++++++++ A couple of books mention, and give plenty of information about, the 68008. All it is is a 68000 with a 8-bit bus, but the instruction set seems to be the same, while the processor hides the 8-bit bus from the programmer by doing double 8-bit fetches in place of 16-bit fetches.... ....just in the same way as the 68000 pretends to be a 32-bit computer in spite of its 16-bit bus. Come to think of it, most 8-bit computers try to pretend half of the time that they are 16-bit anyway. But in this case, the 68008 is specifically designed as an 8-bit imposter for a 16-bit machine with full code compatibility. The book I have found really good for information on the differences on the 68000, -08, -10, -12, and -20 is one published by Osborne/McGraw Hill, called the "68k microprocessor handbook", SECOND edition, published 1986, but I bought my copy a couple of weeks ago at a bookstore in the backwoods (ie, Lexington KY). No one could sanely want to know more about the series than is in that book. So long, Alan Kennington.