LTP port two way communication.
Use buttons or switches for AHK script input and control LEDs or Relays from the outputs.
The LTP port I/O Library was re-upped on 8-21-12. All example scripts and photos were lost in the ahk.net crash.
I've seen many questions asked about this before and now I have a need for it so I've finally figured out how to use AHK for monitoring the parallel port inputs and controlling outputs. We'll I actually I found this link to the German forums where someone had figured it out already and Google Translate helped me figure out what they did.
Read This First!
First a word of warning. I know very little about electronics. Most resources I found suggest using a resistor to protect the LED and an isolator to protect your computer. I had neither of these and was lucky I didn't destroy anything.
It is my understanding that if your computer does not have protection built in to the parallel port a short circuit can fry the mother board. Use caution when using this script and get advice from an electronics tech before connecting anything to your parallel port.
The LPT I/O library.
The dll calls aren't difficult but I've made a library to make it as easy as possible.
LPTInOut.ahk
There are only 4 functions, In, Out, All On and All Off.
/*
Parallel Port Monitor and Controller.
LTP port two way communication.
Use buttons or switches for AHK script input and control LEDs or Relays from the outputs.
http://www.autohotkey.com/forum/viewtopic.php?p=525428
The DLL calls were found in the AHK German forumns.
http://de.autohotkey.com/forum/topic5559.html
[color=brown]LPTInOut_Out(num,port)[/color] ; num is the value relating to the pins to activate. port is the port address.
; This function must be called independently for the first eight and last four pins as they will be
; on two different addresses.
[color=brown]LPTInOut_In(port)[/color] ; port is the port address. Use a timer to constantly check the value present at this port.
[color=brown]LPTInOut_Off(LPTA,LPTB)[/color] ; LPTA is the port number of pins 1 thru 8 and LPTB 9 thru 16.
[color=brown]LPTInOut_On(LPTA,LPTB)[/color] ; These functions need only be called once to controls all 12 pins.
Detailed information can be found below the functions.
*/
; Out
LPTInOut_Out(num,port)
{
DllCall("INPOUT32\Out32",int,port,int,num)
}
; In
LPTInOut_In(port)
{
LTPmon := DllCall("INPOUT32\Inp32",int,Port)
Return, %LTPmon%
}
; All Off
LPTInOut_Off(LPTA,LPTB)
{
DllCall("INPOUT32\Out32",int,LPTA,int,0)
DllCall("INPOUT32\Out32",int,LPTB,int,11)
}
; All On
LPTInOut_On(LPTA,LPTB)
{
DllCall("INPOUT32\Out32",int,LPTA,int,255)
DllCall("INPOUT32\Out32",int,LPTB,int,20)
}
/*
The parallel connector.
This chart identifies the pin numbers as seen on the computer port.
S4 S5 S7 S6 D7 D6 D5 D4 D3 D2 D1 D0 C0
G7 G6 G5 G4 G3 G2 G1 G0 C3 C2 S3 C1
S = Status or input pins.
D = Data or output pins 1 thru 8.
C = Combo or output pins 9 thru 12, in some cases these can be used as inputs.
G = Ground pins.
Each LPT port will have three address, the first is for the first eight inputs, D0 thru D7.
The second for the last four inputs, C0 thru C3. The third for the inputs S3 thru S7.
Note that S0 thru S2 are not included on the connecter.
The typical addresses for LPT1 are,
0x378 for output pins 1 thru 8 or D0 thru D7.
0x37A for output pins 9 thru 12 or C0 thru C3.
0x379 for input pins 1 thru 5 or S3 thru S7.
These may be different on some systems.
*/
/*
LPTInOut_In(port)
Use a timer to constantly monitor the input pins 1 thru 5 (S3 thru S7).
A value will always be present when monitoring, if no pins are activated it will read 120.
-------------------------------------------------------------------------------------------
Here is a short monitoring example script.
^m::
SetTimer, Monitor, 250
Return
Monitor:
lptin := LPTInOut_In("0x379") ; This is the typical address for LPT1.
If lptin = %LastRead% ; Keeps the script from running the associated subroutine everytime the timer runs.
Return ; The subroutine only runs when a new input value is read.
LastRead = %lptin% ; Remembers the last input value for above.
If IsLabel(lptin)
GoTo %lptin%
Return
112:
MsgBox, Pin 1(S3) has been activated.
Return
128:
MsgBox, All 5 input pins have been activated.
Return
-------------------------------------------------------------------------------------------
This chart shows the avallable input values and the combination of pins needed to set them.
1 2 3 4 5
S3 S4 S5 S6 S7
0 = x x x x S3 S4 S5 S6
8 = x x x S4 S5 S6
16 = x x x S3 S5 S6
24 = x x S5 S6
32 = x x x S3 S4 S6
40 = x x S4 S6
48 = x x S3 S6
56 = x S6
64 = x x x S3 S4 S5
72 = x x S4 S5
80 = x x S3 S5
88 = x S5
96 = x x S3 S4
104 = x S4
112 = x S3
120 = All Open
128 = x x x x x All Active S3 S4 S5 S6 S7
136 = x x x x S4 S5 S6 S7
144 = x x x x S3 S5 S6 S7
152 = x x x S5 S6 S7
160 = x x x x S3 S4 S6 S7
168 = x x x S4 S6 S7
176 = x x x S3 S6 S7
184 = x x S6 S7
192 = x x x x S3 S4 S5 S7
200 = x x x S4 S5 S7
208 = x x x S3 S5 S7
216 = x x S5 S7
224 = x x x S3 S4 S7
232 = x x S4 S7
240 = x x S3 S7
248 = x S7
*/
/*
LPTInOut_Out(num,port) Pins 1 thru 8 (D0 thru D7).
Each of the first eight ouput pins are assigned a value shown in this chart.
Pin 1(D0) = 1
Pin 2(D1) = 2
Pin 3(D2) = 4
Pin 4(D3) = 8
Pin 5(D4) = 16
Pin 6(D5) = 32
Pin 7(D6) = 64
Pin 8(D7) = 128
To activate any single pin simply call it's value and the LPT port address.
LPTInOut_Out(1,"0x378") This activates pin 1(D0) on LPT1.
To activate multiple pins, add their values together.
LPTInOut_Out(3,"0x378") This activates pins 1(D0) and 2(D1) on LPT1.
To deactivate all eight pins use the value O.
LPTInOut_Out(0,"0x378")
*/
/*
LPTInOut_Out(num,port) Pins 9 thru 12
These pins behave differently as some of them are normally hot meaning they are active until they receive a value
that deactivates them. For this reason they can not be controled by adding their values. Instead call a value
from this chart.
C0 C1 C2 C3
9 10 11 12
1 x x
2 x x
3 x
5 x x x
6 x x x
7 x x
8 x x
9 x
10 x
11 All Off
12 x x x
13 x x
14 x x
15 x
16 x x x
20 x x x x All On
Example
LPTInOut_Out(8,"0x379") This activates pins 9(C0) and 10(C1) on LPT1.
You should also use the ALL Off call in the autoexecute section of your scripts to have all pins
start in the off state.
LPTInOut_Out(11,"0x379") Deactivates pins 9(C0) thru 12(C3) on LPT1.
or
LPTInOut_Off("0x378","0x37A") Deactivates all output pins on LPT1.
*/
On most computers the parallel port will be LPT1 which is normally going to be at the addresses of 0x378 for outs 1 thru 8, 0x37A for 9 thru 12 and 0x379 for the inputs. The following picture shows the pin configuration.
Red = Out puts 1 thru 8. Orange = Outputs 9 thru 12. Blue = Inputs. Green = Grounds.
This photo and a large part of my education on the subject comes from the article I/O Ports Uncensored by Levent Saltuklaroglu.
Outputs, control up to 12 LEDs or Relays.
All other LPT examples I've seen only allow use of the first eight outputs, 9 thru 12 can be problematic as some but not all are normally powered. The numbers called to control these pins were found by trial and error. The values are listed in the LPT In/Out library.
The first eight pins work by simply adding the values to turn on the correct pins. Values are as follows.
D0 = 1
D1 = 2
D2 = 4
D3 = 8
D4 = 16
D5 = 32
D6 = 64
D7 = 128For example, to use pins D3 and D4 you would call 24. If any pins were already on they are turned off when the new call is made.
To use all 12 pins two calls must be made. The value of the first eight pins along with the address and the value and address of the last four.
LPTInOut_Out(255,"0x378") ; 1 thru 8 on LPTInOut_Out(20,"0x37A") ; 9 thru 12 on
Using the LPT Control script takes care of finding the correct values to call. Just check the box by the pins to use, and set the port numbers in the boxes.
LTP Control.ahk
Inputs, 32 combinations of inputs from five buttons or switches.
The inputs, S3 thru S7 return a combination of thirty two values when activated. To activate I simply grounded the pins using toggle switches. READ THE WARNING ABOVE BEFORE TRYING THIS. The pin combinations are as follows.
0 = S3 S4 S5 S6 8 = S4 S5 S6 16 = S3 S5 S6 24 = S5 S6 32 = S3 S4 S6 40 = S4 S6 48 = S3 S6 56 = S6 64 = S3 S4 S5 72 = S4 S5 80 = S3 S5 88 = S5 96 = S3 S4 104 = S4 112 = S3 120 = All Open 128 = S3 S4 S5 S6 S7 136 = S4 S5 S6 S7 144 = S3 S5 S6 S7 152 = S5 S6 S7 160 = S3 S4 S6 S7 168 = S4 S6 S7 176 = S3 S6 S7 184 = S6 S7 192 = S3 S4 S5 S7 200 = S4 S5 S7 208 = S3 S5 S7 216 = S5 S7 224 = S3 S4 S7 232 = S4 S7 240 = S3 S7 248 = S7
When the port is being monitored the numbers being returned can be used as labels in your scripts. There will always be a number present, if no inputs are active "120" will be read from the port.
This input monitor script watches the port and if a label matching the input value is read it will execute the subroutine. Add subroutines directly to the script using the edit box on the bottom. Activate your switches to set the input value to the desired value. The value is entered into the edit box as a label. Fill in the subroutine and click "Add Subroutine". The new subroutine is added directly to the bottom of the script and the script reloads making it immediately active. Because the input value will still be the same, the new subroutine will run immediately when the script reloads, so beware.
LPT Monitor.ahk
Input Monitor and Output Sequencer.
This overly complex script not only monitors the input pins but allows you to build sequences to control LED lights. The first twelve input values control the outputs in real time making it easy to control the LEDs. Here is a animation demonstrating the five input pins controlling 12 LEDs.
LTP Monitor and Sequencer.
The sequencer;
:arrow: Select the LED lights to use.
:arrow: Enter the time in milliseconds to display the step.
:arrow: Click Record.
:arrow: Click Test to run the sequence.
:arrow: Check Loop to repeat the sequence. Uncheck to stop.
:arrow: Enter a name and save the sequence as it's own AHK script.
Double click a row to delete it.
Right click the first column to adjust the time.
These edits can be made while the sequence is running.
Here is a small vid of a LED sequence. Lost in the ahk.net crash.
Don't forget, all these scripts need the LPT In/Out library.
Thank you for reminding me why there's 13 computer units in my room and I'm still living in the stone age...
