Re: NadaNet for the //c - just an idea

["Ferdinan Meyer-hermann" <ferdinan.meyer-hermann@a2central.com.remove-pk1-this>]

  To: Michael J. Mahon
Michael J. Mahon wrote:

> Cool, Ferdinand!
> 
> I think this could work, provided that a special driver for PB1 was
> added (according to IIc docs, you can't drive a IIc PB input with an
> emitter follower).  Of course, all the needed power is available at
> the disk connector.
One could also use the WRITE PROTECT signal for reading from the net to
allow for a one-connector solution, as the signal can be easily driven by
a '125, which then can also replace the output circuitry above (with the
other three units of an AC125 wired in parallel, one would have 75mA
guaranteed drive capability).

     3x74AC125 in parallel
        |\
PH0-----| >---|>|-----+--------->NadaNet
        |/o           |
          |           |
/EN-----+-+           |
        |             |
        o/|           |
WPROT---< |-----------+
         \|
       74AC125

The signal can be read in the high bit of $C0EE, if the controller ist
configured for checking write protection (STA $C0ED).
> 

> And the send routine always turns off the output, PH0 in this case.
> 
> There is one coding issue--today there is no common "exit" for
> NadaNet, so disabling would require some rework.  (This same
> issue would have to be addressed to deal with IIgs speed control.)
I wouldn't think that there are so many exits that you can't just add an 
STA $C0E8 to all of them (Although thats not a good style)


Ferdinand Meyer-Hermann