Re: Unusual Apple // card

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

John L <jlogo@zip.com.au> wrote:

> I have obtained an Apple // card whose purpose I can't easily
> identify.  The card is called "The Micro Works" with the letters
> "DS-65 (c) 1979" printed directly underneath the title - which is
> located on the top left of the card.  
> 
> On the card itself are a number of small IC's labeled "74LS85N" and
> one large IC labeled "F6821P".  There is also an " DS-65 EPROM II"
> which is socketed as well.  On the top of the card are three trim pot
> wheels with the letters "B" "C" and "W" respectively labeled above
> each pot.

The 6821 is a PIA (Peripheral Interface Adaptor), which is a simple I/O
chip providing two 8-bit parallel I/O ports (with the ability to
configure each pin as either an input or output) and four handshake
signals (two for each parallel port).

> I have a picture at this URL (A bit unclear) if anyone wants a look:
> 
> http://www.zip.com.au/~jlogo/microw.jpg

Any chance you could get a picture from close, and directly above the
card?

I can't see any obvious connectors.  What is the white chip on the right
edge?  (I expect it is the EPROM.)  The components in the top left
corner may also be of interest.

Do any of the small ICs have numbers which _don't_ start with 74LS?  I
see what look like two 8 pin chips.  What are their part numbers?

Is there anything which looks like a crystal, and if so, can you see its
speed rating?

-- 
David Empson
dempson@actrix.gen.nz