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

Ferdinan Meyer-hermann wrote:

  To: comp.sys.apple2
It is just an idea that came to my mind:
The //c does not have Annunciator outputs, so it doesn't allow for the usual
way to connect the NadaNet interface. But I think it might be possible to
do this over the disk port.
One could use pin 11(Stepper phase 0) as the data line and pin 16 as an
enable, like this:

pin 6 (VCC)
--------------------------------+
                              C /
pin 11(PH0)    2.2K           |/
--------------/\/\/\------+---|
                          |   |\       +---> to PB1
                          |   E \      |
                       C /      |      |
pin 16(/EN)            |/       +-|>|--+---> to NadaNet
-----------/\/\/\------|               |
             10K       |\              \
                       E \             /
                          |            \
                          |            /
pins 1-4(GND)             |            |
--------------------------+------------+---> to NadaNet

Now, to send some data, you would need to Initialize:

STA $C0E0       Phase 0 off
STA $C0EB       Select drive 2
STA $C0E9       Drive on

And then, the normal NadaNet send routine can be used, with the Address of
the PH0 softswitch($C0E0/$C0E1) instead of the AN1 switch.
After transmitting, you should turn the drive off, but do not select drive1,
or you will make the drive motor spin up and down:

STA $C0E0       Phase 0 off (if not done by send routine)
STA $C0E8       Drive off, DOS/ProDOS will select correct drive afterwards


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.

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.)

-michael

AppleCrate II: An Apple II "blade server"!
Home page:  http://members.aol.com/MJMahon/

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