			    TEST SOFTWARE
		   FOR THE PARALLEL PORT LINK CABLE

The parallel port link cable is a very simple hardware. You can use it
with a special software (at the moment a patched version of TI's
LINK85X for the TI-85 and George Nachman/Ben Eater's LINK92XP for the
TI-92) to exchange programs, variables, (... zshells :-) ) and to make
a backup.

You can find the latest version (schematic and software) in the www:

	http://www.inf.tu-dresden.de/~aw4/ti85.html
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				EMAIL

Please send me email if you have problems, comments, or suggestions.

	aw4@inf.tu-dresden.de (Andreas Westfeld)
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				HINTS

Here are some hints to build the hardware:

1. You should solder the connections.

2. Check the pin numbering on your parallel port connector. (Some people
told me, that they had mirrored the pin connections first.)

3. Don't use a "normal" 2.5 mm stereo jack, they are different,
especially near the tip. Look at the TI-to-TI link cable shipped with
your calculator. Only this type will get in touch with the socket
inside the TI.

Hints for the software:

link85x can handle grouped (*.85g) and backup files (*.85b) only. If
you have other "types", e. g. *.85s you can siply rename these files
to *.85g using DOS commands:

	ren *.85s *.85g

or

	ren *.85p *.85g

You should connect the cable between TI and PC *after* you start the
link85xp program. Otherwise it is possible that the parallel port is
in a state causing the TI to slow down dramatically (it is not
possible to enter anything in the TI in this state).

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			    TEST PROCEDURE

The link cable is connected to LPT1. The link cable is *not* connected
to the TI, but only to the PC. This is the output on my computer:

LPT1 found at 0278
send 00 - read 00 - should be 00
send 01 - read 20 - should be 20
send 02 - read 10 - should be 10
send 03 - read 30 - should be 30
LPT2 found at 03BC
send 00 - read 30 - should be 00
send 01 - read 30 - should be 20
send 02 - read 30 - should be 10
send 03 - read 30 - should be 30
No LPT3 found.

Notice that the values read match the "should be". After you get this
test successful, you may start lc85.  In this example the right i/o
address is 0x278. You have to start lc85 with the port address as
argument.

	lc85 0x278

After you start lc85, you will get a message to connect the link cable
to the TI. Connect the link cable and select the link menu, send,
program. Select a program and try to transmit it. With a TI-85 you
should have the following output:

LC85 0.01 - see readme for doc.
Author: aw4@inf.tu-dresden.de (Andreas Westfeld)
Using i/o port 0x0278.
Now connect your TI-8x and send a program.
Hit any key to continue.
Waiting for transmission.
Id byte is 0x85
Type byte is 0x06

On the calculator's screen a ERROR 35 LINK	TRANSMISSION ERROR
will be displayed, because only two bytes will be read and not the
whole packet.
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			DISP - THE CALCULATOR
			    SCREEN DUMPER

This little program dumps the screen of your calculator. It switches
to cga mode and draws the display zoomed by factor 2. If there is a
problem with the link connection, please wait for about 4 seconds. The
link will timeout in this case.

To use the program, you have to find out the base i/o address of the
parallel port you use first. If you don't know this address you should
try 0x278, 0x378, and 0x3bc first ;-)

So the command-line could look like this:

	disp 0x278

						      Andreas Westfeld

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Revision history:

29.11.95	ltest101.zip
* timeout added to lc85
* i/o port detection removed in lc85

12.01.96	ltest102.zip
* added disp.com and disp.c

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Files:

lc85.c		source code for lc85.com
lc85.com	test program to read bytes
linktest.asm	source code for linktest.com
linktest.com	test program to check the port and the cable
readme		this file
stdlib.inc,
stdmac.inc	my asm includes (needed for linktest.asm)
disp.c		source code for disp.com
disp.com	test program to get the calculator's display
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