[comp.sys.amiga.hardware] Converting parallel to serial port

a808@mindlink.UUCP (David R. Matthews) (04/11/90)

Maybe I'm off base, but I know that there are devices made specifically to
convert parallel signals to serial, and serial to parallel. I have purchased a
device to convert serial to parallel and tried to no avail to get it working.
Maybe with a device like this and some well written software, you would have
more luck than myself.
If you like, I could find a supplier for these units.
Again, maybe I'm off base.

gt4662b@prism.gatech.EDU (BRANHAM,JOSEPH FRANKLIN) (04/11/90)

In my quest to try and hook up an external terminal to my 1000, someone gave
me a great idea. He claims that the parallel and serial ports on the
1000 are driven by two identical chips.

What I'd really like to do is this:
	make a little board which plugs into where the chip which drives
the parallel port which can make my parallel port act like a serial
port at the flip of a toggle switch.

Questions:
	1) Does anyone know how much off-base this idea is?
	2) Can anyone recommend sources of material about these chips and
		this section of the circuit board?

Thanks in advance,

-- 
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grr@cbmvax.commodore.com (George Robbins) (04/12/90)

In article <7881@hydra.gatech.EDU> gt4662b@prism.gatech.EDU (BRANHAM,JOSEPH FRANKLIN) writes:
> In my quest to try and hook up an external terminal to my 1000, someone gave
> me a great idea. He claims that the parallel and serial ports on the
> 1000 are driven by two identical chips.
> 
> 	1) Does anyone know how much off-base this idea is?

Pretty far.  The modem control lines for the serial port are handled by
one 8520, as are the parallel port data and control lines, however the actual
serial transmit and receive data are handled by the Paula chip.  This is a
unique resource so your switch doesn't seem feasible.

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jms@tardis.Tymnet.COM (Joe Smith) (04/12/90)

In article <7881@hydra.gatech.EDU> gt4662b@prism.gatech.EDU (BRANHAM,JOSEPH FRANKLIN) writes:
>In my quest to try and hook up an external terminal to my 1000, someone gave
>me a great idea. He claims that the parallel and serial ports on the
>1000 are driven by two identical chips. What I'd really like to do is this:
>	make a little board which plugs into where the chip which drives
>the parallel port which can make my parallel port act like a serial port.
>	1) Does anyone know how much off-base this idea is?

Your friend had incomplete information.  The serial port transmit and
receive data is handled by Paula, the custom chip that also handles
floppy-disk read and write, audio output, and analog joystick I/O.

The parallel port is driven by one of the 8250 chips.  The other 8250 chip
is identical, but is connected to the slowly-changing RS-232 signals;
DTR, RTS, CD, CTS, DSR, RI.

You would be better off buying a multi-port serial board.
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valentin@cbmvax.commodore.com (Valentin Pepelea) (04/12/90)

In article <7881@hydra.gatech.EDU> gt4662b@prism.gatech.EDU
(BRANHAM,JOSEPH FRANKLIN) writes:
>
>What I'd really like to do is this:
>
>make a little board which plugs into where the chip which drives
>the parallel port which can make my parallel port act like a serial
>port at the flip of a toggle switch.

You can find serial to parallel and parallel to serial converters from multiple
sources. The price ranges around $40. Pick up a copy of Computer Shopper and
look around.

Valentin

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