Re: Laser128/Laser128EX 1 expansion slot question!

[Tom Greene <tom@cowgod.org>]

On Oct 24, 7:44 am, Steven Hirsch <snhir...@gmail.com> wrote:
> 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 connector on the computer does have +5V, but the expansion box
provides its own +5V supply from an external source. It also derives
-5V from the +12V line.

Tom