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Re: Laser128/Laser128EX 1 expansion slot question!


"Steven Hirsch" <snhirsch@gmail.com> wrote in message ULKdnXqEiaW2KJzUnZ2dnUVZ_qninZ2d@giganews.com">news:ULKdnXqEiaW2KJzUnZ2dnUVZ_qninZ2d@giganews.com...

Michael J. Mahon wrote:

Tom Greene wrote:

On Oct 22, 2:57 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:

The fact that the original expander presented slots 5 and 7 indicates
that both sets of select lines were decoded and that the system was
compatible with this arrangement.

That makes the Laser expansion slot more versatile than a "switched"
slot, since both can be used just by referring to them by slot number.



The Laser slot re-uses a few of the pins (-5V, for one) to carry slot
5 select signals in addition to slot 7, otherwise it is pretty much
equivalent to slot 7 on the IIe. The pinout is:

1:     IOSEL slot 7
2-17:  A0-A15
18:    R/W
19:    CSYNC
20:    IOSTB
21:    RDY
22:    DMA
23,24: n/c
25:    +5V
26:    GND
27:    n/c
28:    DEVSEL slot 5
29:    NMI
30:    IRQ
31:    RST
32:    INH
33:    -12V
34:    IOSEL slot 5
35:    3.58M
36:    7M
37:    Q3
38:    Ph1
39:    CPU SYNC
40:    Ph0
41:    DEVSEL slot 7
42-49: D7-D0
50:    +12V

And here's the expansion box schematic from the Laser 128 technical
manual:
http://cowgod.org/apple2/laser128-expansionbox.png


*Very* interesting!

So a card that uses -5v won't work if plugged into the side of the
machine, but will work fine plugged into the expansion box!
And, unless I'm misreading something, +5v is similarly MIA at the computer connector. Or, does that simply mean that the expansion chassis fails to make use of it?
The +5v signal is right where it always is on pin 25. 
Bill Garber from GS-Electronics
http://www.garberstreet.com
"If you wish to forget anything on the spot, make a note that this thing is to be remembered." (Edgar Allen Poe)