[aprssig] Position mapping

'Scott Miller' scott at opentrac.org
Thu Jun 28 12:04:32 EDT 2007

What is it exactly that you're trying to accomplish?
The C-64 had a flat 64k address space, with no MMU and no protection of any
sort, so you could read or modify any address in memory.  Things are more
complicated these days - see http://en.wikipedia.org/wiki/Memory_protection.
If you're talking about getting access to I/O, though, that's another
matter.  Easiest way to do that with no extra hardware is to use the
parallel port, if you just need a few pins.  I honestly don't remember how
to do it, but there are FAQs out there.  My Linux box hasn't been powered up
since I moved, so I can't look at my old code.  I wrote a small script for
controlling the DR-112 radio I was using for my IGate - I just wired the
channel-up and channel-down pins of the mic connector to a couple of
transistors and connected it to the parallel port so it could automatically
change channels for PCSAT operation.
If you need more I/O than that, you can get commercial data acquisition
boards.  I've got a 56 bit digital I/O board that I use under Windows:
I think it cost me around $120, but I really don't remember for sure.  I
find it useful for testing out interface code.  For example, I wired it up
to a SED1330F graphical LCD panel and prototyped all of the code to drive it
in Visual Basic.
I'm sure there are cheaper hobby-oriented components out there.


From: aprssig-bounces at lists.tapr.org [mailto:aprssig-bounces at lists.tapr.org]
On Behalf Of Andrew Rich
Sent: Thursday, June 28, 2007 1:24 AM
To: Aprssig
Cc: ozaprs
Subject: [aprssig] Position mapping

In the early days I used to peek and poke in the commodore 64.
I am wondering if something like this exists in linux ?
I am trying to play with ultrasonic radars 
Andrew VK4TEC

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