Using matlab to control LPT port

28 sec read

Download the following 4 files:

  1. porttalk.sys, copy to C:\WINDOWS\system32\drivers
  2. lptread.m
  3. lptread.mexw32
  4. lptwrite.mexw32

Copy the last three files to a directory where your matlab can access.

Your LPT port number is probably 0x378 (or 888). Assume lptport is the port number, then we use lptread to read from the port:

val = lptread(lptport)

and use lptwrite to write to the port

lptwrite(lptport, val)

As a real example, we want to control the step motor Gary created to investigate motion artifact in fMRI. Here is a sample code:

lptport = hex2dec('378');
dir = hex2dec('40');
data = hex2dec('20');
for ii=1:30
lptwrite(lptport, data+dir);
lptwrite(lptport, dir)

Author of lptread.m: Erik Flister, UCSD, 2006. Adapted from Andreas Widmann.

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5 Replies to “Using matlab to control LPT port”

  1. sorry, i couldnt access this command in matlab asked to download four file but it didnt work .there is a command error about lptread and lptwrite.

    if there are any solution different than this please re send

    thanx in advance

  2. Undefined function or variable ‘lptwrite’.

    Error in lptdeneme (line 5)
    lptwrite(lptport, data+dir);

  3. I have Windows 64-bit, and the MATLAB cannot recognize the lptwrite function.
    I get the following error
    Undefined function or variable ‘lptwrite’.

    Does lptwrite only works on 32-bit? Could you please help me with this?


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