16 Oct
2001
16 Oct
'01
6:34 a.m.
On Tue, 16 Oct 2001, Ethan Dicks wrote:
I recently "helped" a friend by accepting a largeish box of discarded
engineering samples, etc., when his employer cleaned house. In the
box of assorted (and unsorted ;-) ICs were a quantity of 74170Fs (and
54170Fs. I have quite a few 54-series parts from places that spent
big bucks for protyping supplies then threw them out later), maybe 20-30.
Not recognizing the part number, I turned to the 'net to look them up. So
they are a "4x4 O.C. register file"... The only thing I could think to use
them for would be SSI/MSI microprocessor implementations. Did they have a
typical use?
We used the ls version of the 170 in 1983 for Z80 memory mapper - part of
a CPM era disk emulator that plugged into a Z80 socket The mapper divided
64K into 16 4K blocks which could be original (passthrough) memory or
mapped memory on our card. The 170 is sort of the little brother of the
ls612 that is used as the DMA memory mapper to extend the 8237s address
range on the IBM AT
I've also seen the 170 (or 670 the 170's tri-state version) used in
70's vintage processors - the Diablo Hytype II uses a bits-and-pieces
processor that uses '170s...
One cool side effect of going through all these chips - most of them have
date codes from 1969 - 1978. Nice for repairing vintage machines with.
-ethan
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Peter Wallace
Mesa Electronics