26 Apr
2001
26 Apr
'01
12:06 a.m.
a couple of questions:
does anyone have a spare 16MHz 68k CPU (or a source in the UK who may sell
them - Maplins don't). There must be lots somewhere gathering dust since
everyone moved to the later 68k family chips (all I have spare are the stock
8MHz versions). Lots of non-home-computer stuff seems to use them (phone
exchanges, network equipment, video processing boxes etc.).
also, does anyone know of anything that used 68450 chips? (they're 4-channel
DMA controllers for the 68k apparently). I found a couple of these amongst
the piles of junk I have and am curious as to where I might have got them -
I can't think of anything I've ever stripped for parts which may have used
them! :-)
cheers
Jules
26 Apr
26 Apr
9:14 a.m.
--- Julian Richardson <JRichardson(a)softwright.co.uk> wrote:
a couple of questions:
does anyone have a spare 16MHz 68k CPU...
Was the MC68000-12 rated to 16Mhz, or did people just run it that fast? I
remember it was an issue for people who tried to clock-double their A500s.
also, does anyone know of anything that used 68450
chips? (they're 4-channel
DMA controllers for the 68k apparently).
I've seen at least one Amiga peripheral that used a Motorola DMA chip (forget
if it was 2-channel or 4-channel). Microbotics SCSI? Software Results had
a WAN router box that was never released, that used a 68450 per serial card
for high-performance serial (vs the non-DMA 8-port low performance card). I
doubt if you got it from that - I have the boxes (and 8-layer boards!) up
in the attic. ISTR they used 600 RPM 3.5" drives, too.
In the Motorola world, DMA went on the peripheral; in the Intel world, DMA
went on the motherboard.
-ethan
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12:54 p.m.
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3:36 p.m.
--- Tony Duell <ard(a)p850ug1.demon.co.uk> wrote:
The ones I've seen were 64 pin DIL for the 4-channel and, I think, 40 or
48 pin DIL for the two channel. I've never seen a PGA version myself.
-ethan
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also, does
anyone know of anything that used 68450 chips?
In a 64 pin DIL package or a 68 pin (?) PGA package?
3:42 p.m.
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27 Apr
27 Apr
6:23 a.m.
Tony Duell wrote:
...I am sure there was a PGA version....
I don't suppose anyone has the pinout of the 2-channel (68440 IIRC) DMA
chip, do they (as a plain text file). I'll need it sometime in the
distant future for repairing a little HP 68K computer I have here...
Thanks in Advance for any help.
-tony
I have the pinout here in my M68000 Family Reference Manual. I could
find some way to replicate it in ASCII sometime between now and "the distant
future". :)
I have a Hitachi 68450-10 and a Motorola 68451-10 -- both PGA -- that I
dug out of a bin of chips at the local computer bastardization and surplus
hell-hole. Someday they'll go into my fabled homebrew Linux/68K machine.
Heh. Right. Does anybody happen to know what the 68451 actually is? I've
been assuming it is some slight variation on the 68450, but I don't have any
documentation that actually says so outright.
--
Joel Ewy
mailto:ewy@_spamaway_southwind.net
http://www2.southwind.net/~ewy
8:40 a.m.
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28 Apr
28 Apr
4:24 a.m.
--- Tony Duell <ard(a)p850ug1.demon.co.uk> wrote:
Not even close IIRC. The 68451 is an MMU. I've
only seen it as the 64 pin
DIP version, again in the XXX (which has 3 64 pin chips on the CPU board
(aka 'Stickleback'!) -- the 68000, 68450 and 68451.
Must have been some sort of Motorola reference design. The Software
Results "Node Box" I mentioned has a DIP 68451, too. We never got
the software that far advanced, so I have a DIP socket, wired to
bypass the MMU. Just drop it in, and the system works without
memory management.
It is listed as obsolete by Motorola because it is _not_ compatible
with the later, and more common, 68851 that was used with the 68020.
-ethan
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8:45 a.m.
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8 comments
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participants (4)
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ard＠p850ug1.demon.co.uk -
ethan_dicks＠yahoo.com -
ewy＠southwind.net -
JRichardson＠softwright.co.uk