[comp.sys.amiga] Amiga Parallel Port

plw@rayssdb.ray.com (Paul L. White) (12/20/89)

The documentation on the Amiga parallel port is sketchy at best.  The 
information I seek is with regard to the STROBE and BUSY signals on
the port.  Are these signals handled by the hardware or must the signals
be dealt with via software instructions?

My father owns a unit which interprets weather satellite broadcast information
and sends the information to a printer.  He'd like to be able to connect the
unit to the Amiga 1000's parallel port and write a program to print the image
to the monitor.  The documentation makes it very clear that the parallel port
is "usually used for output to a printer."  The port's pin-outs are also     
provided in the documentation.  Unfortunately, although this startling information is wonderful, it just doesn't change the baby's diapers.

If anyone can provide the information on the parallel port, or even better
if anyone has already written a software module in this vein, it would be
a wonderful Christmas present.

Thanks in advance....

=============================================================================
Paul White
42 Lawton Ave. #5
Tiverton, RI 02878
(401)625-5183
==============================================================================

valentin@cbmvax.commodore.com (Valentin Pepelea) (12/21/89)

In article <3959@rayssdb.ray.com> plw@rayssdb.ray.com (Paul L. White) writes:
>
> The documentation on the Amiga parallel port is sketchy at best.  The 
> information I seek is with regard to the STROBE and BUSY signals on
> the port.  Are these signals handled by the hardware or must the signals
> be dealt with via software instructions?

The STROBE signal is generated by the hardware, while the BUSY signal must be
generated by the software.

> My father owns a unit which interprets weather satellite broadcast information
> and sends the information to a printer.  He'd like to be able to connect the
> unit to the Amiga 1000's parallel port and write a program to print the image
> to the monitor.  The documentation makes it very clear that the parallel port
> is "usually used for output to a printer."  The port's pin-outs are also     
> provided in the documentation.  Unfortunately, although this startling
> information is wonderful, it just doesn't change the baby's diapers.

All he has to do is make a special parallel cable. Ever heard of null-serial
cables? Well, here is how to wire a null-parallel cable:

AMIGA			    SENDING UNIT

  1    ---------\ /---------     1	*STROBE
                 X
 10    ---------/ \---------    10 	*ACK

2-9    ---------------------   2-9	D0-D8

 11    ---------------------    11	BUSY
 12    ---------------------    12	POUT
 13    ---------????--------    13	SEL
 14    NO CONNECT			+5V
 15    NO CONNECT			NC
 16    WHO CARES			*RESET
 17    \                   /    17	GND
        -------------------		necessary to connect only one of 17-25
 25    /                   \    25	GND

Under penalty of death, do not connect pin 14. You may not connect the SEL pin
to the device and the RING pin on the serial port to the modem simoultaneously.
Internally these pins are connected together.

>If anyone can provide the information on the parallel port, or even better
>if anyone has already written a software module in this vein, it would be
>a wonderful Christmas present.

"It's in there." It is called the parallel.device. The amiga generates an
interrupt internally when the *ACK signal is asserted, and it asserts the 
STROBE signal whenever a byte is read in or written out the parallel port.
By switching pins 1 and 10, the Amiga looks like a printer to the outside world.

You must send a CMD_READ to the parallel.device before the sender sends out its
first byte, otherwise the transfer will lock up.

If you do not wish to bother with the parallel.device, you may download data
from the sender by issuing "type from par: [to filename]" at the cli prompt.
Unfortunately the type command will not know when the transfer is complete,
so it will never terminate.

Be careful no to set your Amiga and the sender to read simoultaneously, nor to
write simoultaneously. Doing so will result in blowing an 8520 in your Amiga.

"And they said you could blow damage your hardware through software..."

Valentin
-- 
The Goddess of democracy? "The tyrants     Name:    Valentin Pepelea
may distroy a statue,  but they cannot     Phone:   (215) 431-9327
kill a god."                               UseNet:  cbmvax!valentin@uunet.uu.net
             - Ancient Chinese Proverb     Claimer: I not Commodore spokesman be

koshy@abekrd.UUCP (Koshy Abraham) (12/21/89)

plw@rayssdb.ray.com (Paul L. White) writes:


>If anyone can provide the information on the parallel port, or even better
>if anyone has already written a software module in this vein, it would be
>a wonderful Christmas present.

I have an EPROM programmer interface with software coming out in the next 
issue of Transactor for the Amiga (U.K.). The hardware for this may be used
as i/o ports so you can connect other devices to it. The software deals with
all the interfacing for the programmer through this interface.

If you need the interface, I can try and draw it up using DPAINT and
uuencode it and send it to you by e-mail. The source code comes to about 200K
in total, but I can send you the interface code (Interface.c). If you need it
e-mail me.

Alternatively I can send you a copy of Transactor for the Amiga when it comes
out in January.

Koshy.

-- 
Koshy Abraham               NET: koshy@abekrd.co.uk
Abekas Video Systems Ltd.  UUCP: ...!mcvax!ukc!{reading,pyrltd}!abekrd!koshy
12 Portman Rd,   Reading, PHONE: +44 734 585421      //     |<= This looks
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