SYM-1 vs KIM-1 (was Re: MOS Kim-1 Any idea of it's worth/value?)

[Pete Turnbull]

On Apr 13 2005, 20:51, Ethan Dicks wrote:
> On 4/13/05, Dwight K. Elvey <dwight.elvey at amd.com> wrote:
> > >What's the part number?  I might be able to help (I have tubes of
> > >8641s, for example).
> >
> >  I'm looking for a DP8303 but with some software
> > changes I could most likely get a DP8304 to work.
>
> Oooh... you are right... that is an unusual one.  I don't even
> recognize the number.  Do you have specs?  Would it be possible to
get
> the right functionality (current drive, etc.) with more than one chip
> on a daughter card and plug it into the socket for the DP8303?
>
> Wish I could help.
>
> Wonder why they picked something that was so far out of mainstream.

They weren't unusual; I've seen quite a few on early 8-bit machines.
 The DP8304 is an octal tri-state non-inverting bidirectional
transceiver, with PNP inputs and 48mA/300pF drive capability on the B
outputs, 16mA on the A outputs (all of which are TTL and MOS
compatible).

        ___ ___
    A0 | 1  20 | Vcc
    A1 | 2  19 | B0
    A2 | 3  18 | B1
    A3 | 4  17 | B2
    A4 | 5  16 | B3
    A5 | 6  15 | B4
    A6 | 7  14 | B5
    A7 | 8  13 | B6
    CD | 9  12 | B7
   GND |10__11_| TRAN/notREC

CD is Chip Disable; low enables the tri-state outputs
TRAN/notREC low makes A output and B input
TRAN/notREC high makes A input and B output

DP8303 is the same but inverting; DP8307 and DP8308 are similar but
with separate Transmit and Receive inputs.  All were still current when
my 1996 Nat Semi databook was printed, but the DP8304 was the most
common, in my experience.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York