As Steve mentioned, the M100 parallel port is non-standard. It has
output buffers with series resistors on all of the data output pins.
This means they cannot be used for either input or for any meanigful
power harvesting.
For input, there are only 2 signals, BUSY and BUSY_N. Each of these can
be read independenty.
Ken
On 1/4/21 11:44 AM, Tom Wilson wrote:
The Centronics standard has 5 dedicated input status lines. And you
only need 5 signal pins for an Atari joystick.
Is it possible to read the pins directly? If so, then it should be
possible.
Tom Wilson
wilso...@gmail.com <mailto:wilso...@gmail.com>
(619)940-6311
K6ABZ
On Mon, Jan 4, 2021 at 11:42 AM Stephen Adolph <twospru...@gmail.com
<mailto:twospru...@gmail.com>> wrote:
m100 parallel port is output only except for the printer status
lines. GPO yes but not GPI...
On Mon, Jan 4, 2021 at 2:39 PM Tom Wilson <wilso...@gmail.com
<mailto:wilso...@gmail.com>> wrote:
> Seems to me that somebody had a scheme a while back where
the joystick interfaced with the parallel port and status was
polled that way (this avoids having to build a custom interface).
Yeah, we used to use the parallel port for a lot of things,
back in the DOS days; it doesn't take much to make it an 8-bit
GPIO, and I used to have a sound "card" that used the parallel
port.
I think there are just enough status lines to pull off using
it for a joystick:
https://en.wikipedia.org/wiki/Parallel_port#/media/File:25_Pin_D-sub_pinout.svg
Tom Wilson
wilso...@gmail.com <mailto:wilso...@gmail.com>
(619)940-6311
K6ABZ
