Re: Apple card to identify...

[dempson@actrix.gen.nz (David Empson)]

Joseph Barbey <joseph.m.barbey@uwrf.edu> wrote:

> I have posted a few jpegs of a card I was recently given.  They can be
> found at www.uwrf.edu/~jb0w/images/  The particular pictures are 
>   card_connector.jpeg
>   card_connector2.jpeg
>   main_card.jpeg

Good pictures!

> card_connector.jpeg's main connector is an RJ-45, as in 10bT.  I'm
> guessing this is NOT in fact a networking card.

Doesn't look like it.  The only distinctive point I can see on the card
is that it has two 8KB RAM chips (the two 6264s).  The surface-mount
chip could be anything (a single chip micro seems a good bet), and the
lack of a manufacturer on the PCB doesn't help.

The large number of resistors near the ribbon cable implies some kind of
analog interface externally, but it doesn't look like RS-232 (no sign of
standard RS232 level converter chips).  It might be a parallel
interface: the '240 chips are buffers, and most of the resistors are 100
ohms, so are probably for current limiting.

Going through the logic chips on the board gives the following:

74HC14               Hex schmitt-trigger inverters

74HC112              Dual J-K negative edge triggered flip flops
                     with preset and clear

74HCT123             Dual retriggerable monostable multivibrators
                     with clear

74HC240 (x2)         Octal buffer/line driver/line receiver
                     with inverted 3-state outputs

74HCT32              Quad 2-input OR

74HCT74              Dual D-type positive edge triggered flip flops
                     with preset and clear

96LS02               Not sure - might be quad 2-input NOR (74LS02)

A710 (x2)            No idea

SED1314F (QFP)       No idea

I expect the HCT74 is at least partially used for implementing the
IOSTROBE area ($C800-$CFFF), and the HCT32 may be tied into this as
well.

No EPROM - there might be one inside the surface mount chip, but I doubt
it.  This implies no firmware on the card, hence it would depend on
matching application software to run the card.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand