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From: Valeriy on 18 Mar 2010 01:54
Hi all

I am controlling two stepmotors par LPT port, applying output signals
via Data1..Data8 lines (pins 2..9 of 25-pin DSUB). Now I need to use
two additional pins to control some attached equipment. I'd like to use
pins 14 (AutoFeed) and 16 (Init) of the same connector.

To see the output levels of LPT lines I am using small, free, and useful
utility LPT port monitor:
http://www.softpedia.com/get/Network-Tools/Network-Monitoring/Parallel-Port-Monitor.shtml
It allows to see the output levels and to change them.

Initialization of LPT port is following:

parport=digitalio('parallel',1);
lineSM=addline(parport,0:7,'out'); % Pins 2-9
lineX1 = addline(parport,14,'out'); % Pin 14
lineX10 = addline(parport,16,'out'); % Pin 16

To change the level of ouput lines I use following command:

putvalue(lineX1,1);
putvalue(lineX10,0);

as well it can be following command:

pval(8) = 0; % pin 14
putvalue(parport,pval)

LPT port monitor shows correct changing of the state of pins 2-9, as
well as pins 14 and 16.

Problem is absence of changing of output tension on pins 14 and 16, (it
is all times logical 0) while output tension on pins 2-9 are in exact
correspondence to applied command and to indications of LPT monitor.

I have changed BIOS options of LPT port from Normal (Standart) to
Bidirectional without success in solving of this problem.

LPT port works well, I can print some documents by a printer.

Experiment with another computer, corresponding cables etc. gives the
same result.

Thanks for any ideas

Valeriy
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