From: Jim Brain (brain_at_jbrain.com)
Date: 2007-11-07 01:29:51
Ethan Dicks wrote:
> On 11/7/07, Jim Brain <brain@jbrain.com> wrote:
>
>> My thought was the cost of finding the connectors. For a user port, you
>> could rob an old modem (though I generally discourage hacking antique
>> CBM items, I can make an exception for any 1660 variant). The cassette
>> port is a bit harder to find, though game carts exist in the plenty. As
>> well, a small PCB with just the card edge is a mere buck to produce and
>> sell for those who want a nice looking setup.
>>
>
> I don't recall either the 6-pin (cassette port, single-sided) or the
> 24-pin (user port, double-sided) connectors being particularly
> difficult to find. They aren't as inexpensive as, say, a DE9 or DB25,
> but they are still being made, AFAIK.
>
> The usual places I start with are Jameco, Digikey, and Mouser. The
> connectors are ordinary 0.154" spacing edge connectors.
>
>
DigiKey has them in stock, it's just the minimums from places like
DigiKey that thwart many a project. I suppose that if you were building
this, you'd buy a handful of them and hit the minimums.
To carry the consensus feeling forward, how would folks use the user
port for networking? I know Centipede 128 used a simple 1-1 connection
to hook two machines together, but I've not seen other uses.
Hooking all 8 data lines across 64 machines will not work due to fanout,
so you have the following options:
* Use SP1/CNT1 as an input, and SP2/CNT2 as an output. Transfers
are limited to CLK/32 bytes/sec or 31K theoretical.
o This allows a 4 wire data connection, though one might want
to add an ATN wire to denote commands on input and output.
* Use 4 bits of PB for inputs, and 4 for outputs.
o More bits, but CLK/8 speed max.
Any other ideas?
--
Jim Brain, Brain Innovations (X)
brain@jbrain.com
Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times!
Home: http://www.jbrain.com
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