Tom Greene wrote:
> On Oct 22, 2:57 pm, "Michael J. Mahon"  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!

-michael

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