Subject: Re: Z8530SCC
Newsgroups: comp.sys.apple2
From: dempson@actrix.gen.nz (David Empson)
Date: Mon, 29 Nov 1999 01:14:00 +1300
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Frank Carney <frankc@cyberhighway.net> wrote:

> Okay, I opened up my IIGS and noticed that it uses a Z8530SCC.
> Well I searched the web and can only find a pinout for the 40 pin dip.
> Can anyone direct me to the pinout for the chip type (not sure what it
> is called) in the GS?

Judging from the circuit diagram, it is the 44 pin PLCC version (Plastic
Lead Chip Carrier, sometimes called "J-lead", since the pins are shaped
like the letter J and tucked under the chip).  It might be a QFP (Quad
Flat Pack), but I doubt it, since nearly all the motherboard chips are
PLCC.

Why do you want to know the pinout, anyway?  You can't do very much
directly to the serial chip on the IIgs motherboard.

If this is related to your previous post about RS-422 vs 232, then you
are looking in the wrong place - the Z8530 uses TTL level signals, and
there are external chips which convert to the appropriate line levels.
On the IIgs, these chips are a 26LS32 (input) and 26LS30 (output).
There are two of each chip (one for each port).

Here is the pinout, according to the IIgs Hardware Reference circuit
diagram.

 1  D0              23  PCLK.L
 2  D1              24  DCDB.L
 3  D3              25  CTSB.L
 4  D5              26  RTSB.L
 5  D7              27  DTR/REQB.L
 6  INT.L           28  ?
 7  ?               29  TXDB.H
 8  IEI.H           30  TRXCB.L
 9  INTACK.L        31  RXDB.H
10  Vcc             32  RTXCB.L
11  ?               33  ?
12  SYNCA.L         34  ?
13  RTXCA.L         35  GND
14  RXDA.H          36  SEL
15  TRXCA.L         37  C/D.L
16  TXDA.H          38  CE.L
17  ?               39  A/B.H
18  ?               40  WR.L
19  DTR/REQA.L      41  RD.L
20  RTSA.L          42  D6
21  CTSA.L          43  D4
22  DCDA.H          44  D2

The pins are numbered from the middle of one edge (marked with a dot),
then anticlockwise.

I don't have a full pinout for the PLCC version.  It isn't covered in my
databook, and we've only ever used the DIP version at work.

Looking at the DIP version, the missing signals include:

W/REQA.L (probably pin 11)
SYNCB.L  (probably pin 33)
W/REQB.L (probably pin 34)

The other ones are probably ground or power lines.

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