[sdiy] Keyboard scanner IC

[Roy J. Tellason]

On Monday 26 January 2009 02:04:01 am Andre Majorel wrote:
> On 2009-01-25 17:26 -0500, Nathan M. Reeves wrote:
> > The keyboard is scanned by U1, which is a mask-programmed 6502-variant.
>
> [...]
>
> > Now on the schematics I  downloaded from tom (the original Mirage I
> > believe), things are a bit off from what I see inside the Mirage DSK I
> > am working over...
> >
> > on mine
> > U1 SN74LS145N
> > U2 7406N
> > U3 7407N
> > U4 R6522AP
> > U5 WD1772-PH
> > U6 1380650001
> >
> > on the schematics
> > U1 6500/11 MCU
> > U2 LM339N
> > U3 NE555
> > U4 6N138
> > U5 LM339N
> > U6 74LS145
> >
> > So on my unit U6 is what U1 is on the schematic?  the 6502 variant MCU?
>
> If your unit has a CPU, it has to be U6. U4 (6522) and U5 (1772)
> are not CPUs and the others are SSI chips. I don't recognise that
> "1380650001" number, however.

The 6522 is a parallel interface chip,  used also in the VIC-20 and the 1541 
disk drive,  I have some if anybody needs some.  The 1772 is a floppy 
controller interface chip,  I don't have any of those.

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin