[sdiy] LocalTalk ISA Card design

[Magnus Danielson]

Dear folks,

Sometimes I am not fully accountable for my actions and today was one of those
days. We had sun, thunderstorm and sun again, so summer has arrived.

Anyway, a friend of mine found an Apple LaserWriter which works, but he is not
a Mac guy (and has in inclination to become one) and it only talks LocalTalk.
But, you can never be without resources.

The Mac implements the LocalTalk with the Zilog 8530 SCC, RS-422 drivers and
receivers and a 3,6864 MHz clock. So, we got a AMD 8530, 26LS31, 26LS32 and
a TTL 3,6864 MHz oscillator. Then toss in a 8-pos DIP-switch and a 74HC688 to
convert the A9-A2 and AEN to a CE on the 8530 and away you rock. I had a
wirewrap labcard for 8-bit ISA lying around for him to have (actually I had 5
so he could have one.. ;O) and he also backed up on wirethreads.

We have already looked some on the driver side and yes, a few mods of existing
drivers is needed, but nothing really major to get it cooking under Linux.

Conclusion: there isn't a stupid problem which shouldn't be possible to solve
by some good old DIY!

Cheers,
Magnus