How to access parallel port for Windows XP using C++?

[Lucifre]

I Have Windws XP and i want to access my parallel port using C++. I have heard that it is hard to do it in this operating system. Are there any tutorials anywhere on the net that would teach me how to access parallel port specifically for windows XP, using just plain old dev C++?

I heard that it is not a problem with, Visual C++ or Borland C is that true?

thanx foe help

 

[DrBob13]

Re: C++ Questions

Hi,
You need this inpout32.dll in your windows system directory and you should be OK with XP at least, I have used it under this OS to drive a bit of kit and read sensors etc. that I bult. I used visual C++ but it works OK with Borland and Python etc.

**broken link removed**

I have not used it with a virtual parallel port but it is OK with the standard parallel port. Will probably work OK though, similar dlls work OK with serial ports.

This url is useful too.
**broken link removed**

Bob.

 

[Lucifre]

Re: C++ Questions

hold on... all i need to do is to put inpout31.dll in my windows directory, and program as if i was in win 98? is it that simple? or do i need to call this dll somewhere in my code?

sorry im new to programming.

and where do i get this inpout31.dll?

thanx for replying

Added after 12 minutes:

and where exactly do i put this dll?

 

[DrBob13]

Re: C++ Questions

Hi,
You can download it from the logix4u link at the bottom of the page that I gave you in my previous post. Copy it into the C:\Windows\System directory, that you will find as a sub directory under Windows on your C drive.

I have posted some C++ code that I use to drive what I call my CNC mitre box that is used to cut the fret wire slots in guitar fretboards, so that you can get an idea how to use the dll, I think there are enough comments in the simple console display example code printed below for you to understand the bit that handles the access to inpout32.dll.

I do not know what programming language you are happy with, but the code below will compile OK in Visual C++6, it does need the inpout32.lib included in the project to link OK but that is in the zip file that you will download with the dll.
Best of luck
Bob.

/* Fret Cutting System Control Program

Version 1.0.

Written by R. A. Currell (Roseland Audio) October 2005.

Array location addr[3] is used as a scratchpad reflection of the parallel output port
Array location addr[4] is used as a scratchpad reflection of the sensor array
*/

#include <iostream>
#include <math.h>
#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>

#include "stdafx.h"

/*   ----Prototypes of Inp and Outp--- */

short _stdcall Inp32(short PortAddress);
void _stdcall Out32(short PortAddress, short data);

/*	 Please Note: This function requires InpOut32.dll to be loaded in the Windows System Directory.
	(See Logix4u website for the dll, its coding and usage */
 /*--------------------------------*/


// Prototype function definitions.

float GetScaleLength(void);
int GetFretNumber(void);
void CalcFretPosition(int,float,float[]);
void GoToZeroFret(int[]);
void CalcLeadscrewRotations(float,float,int,int,float[],int[]);
void ClockParallelPort(long,int,int,int[]);
void MoveSawToFretPos(int,int[],int[]);
void Delay(int);
bool Sensor(int[]);
int ReadSensors(int[]);
float GetLeadScrewPitch(void);


main()

{
	float Length, Fret[50], StepsPerRev;
	int FretNum,Steps[50],addr[4],GearRatio;
	double LeadscrewPitch;

	addr[0]=0x378, addr[1]=0x379, addr[2]=0x37a, addr[3]=0x62, addr[4]=0;

//	LeadscrewPitch = 0.9170;//Measured pitch of M6 threaded Studding used for prototype leadscrew.
	StepsPerRev = 44;		//Resolution of RS Stepper Motor type 351-4580.
	GearRatio = 8;			//Gear Ratio built into unit.

	LeadscrewPitch = GetLeadScrewPitch(); //Read leadscrew pitch from calibration file.
	Length = GetScaleLength();
	FretNum = GetFretNumber();
	CalcFretPosition(FretNum,Length,Fret);	//Values of spacings calculated are in mm
	CalcLeadscrewRotations(LeadscrewPitch,StepsPerRev,GearRatio,FretNum,Fret,Steps); /*Calculate number
																	//	of Steps to next fret*/
	GoToZeroFret(addr);
	MoveSawToFretPos(FretNum,Steps,addr);	//Position Saw guide to next fret position.

	return 0;
}


float GetScaleLength(void)

{
	char units;
	float ScaleLength;

	printf( "\nDo you wish to use Metric or Imperial units (m or i) ? ");
	units=(tolower(getche()));

	if (units == 'm') 
	{
		printf("\n\nPlease input the scale length to be used in millimeters? ");

		scanf("%f",&ScaleLength);
	}
	else 
	{
		printf("\n\nPlease input the scale length to be used in inches? ");
		scanf("%f",&ScaleLength);
		ScaleLength=ScaleLength*25.4; //Convert imperial scale length in inches to mm.
	}

	return ScaleLength;

}


int GetFretNumber(void)

{
	int fretNumber;

	printf("\nPlease specify the number of frets to be used on the scale? ");
	scanf("%u",&fretNumber);

	return fretNumber;
}


void CalcFretPosition(int Fretnum, float Scale, float Fret[])
{
	double FretConst;
	int i;

	Fret[0]=0;

	FretConst = (1/(exp(log(2)/12)-1))+1;

	for (i=1;i<Fretnum+1;i++) Fret[i]=Scale/FretConst;

	for (i=1;i<Fretnum+1;i++) Fret[i]=((Scale-Fret[i-1])/FretConst)+Fret[i-1];
	return;
}


void CalcLeadscrewRotations(float Pitch, float StepperRes, int Gear ,int FretNum,float Fret[], int Steps[])

{
	float StepsPer_mm;
	int i;
	Steps[0]=0;
	
	StepsPer_mm = StepperRes*Gear/Pitch;

	for (i=1;i<FretNum; i++)
	{
		Steps[i]=int(float((Fret[i]-Fret[i-1])*StepsPer_mm));
	}
	return;
}


void ClockParallelPort(long clocknum,int del, int dir, int addr[])
//Generate a clock on Bits 1 and 2 of the parallel port and set the direction as specified.

{
int clock=0x03, drivemotor=0x20, i;

	addr[3]=((addr[3]^drivemotor)&0x7f)|dir;

	for (i=0; i<clocknum; i++)
	{
		addr[3]=addr[3]^clock;
		Out32(addr[0],addr[3]);
		Delay(del);
		if (kbhit()) break;
	}
	addr[3]=addr[3]|0x30;
	Out32(addr[0],addr[3]);	//Turn off the motor power (Bits D5 & D6 both set to 1)
	return;
}


void MoveSawToFretPos (int fretnum, int Steps[], int addr[])
{
	int i,j,del,dir;

	del = 3, dir = 0x00;
	printf("\n\nThe saw carriage is now positioned at Fret 0 (or the nut if no zero fret).");
	printf("\n\nPlease set up the finger-board and fix it ready for sawing the fret slots.\n\n");
	for (i=1; i<fretnum; i++)
	{
		j=Steps[i];
		printf("\nPlease press a key to move saw to the next fret position. Next fret number is %u",i);
		while (!kbhit());
		if (getch()=='\x1b') break;
		ClockParallelPort(j,del,dir,addr);
	}
	printf("\n\n");
	return;
}


void Delay(int del)

// Delay routine. Approximate Delay =  del times 1 millisecond.
{
	int i,duration;
	duration =del * 400000;

	for (i=0; i<duration; i++);
	return;
}


void GoToZeroFret(int addr[])
// Find the zero point from anywhere beyond zero (at Sensor 1)!
{
	int dir,start;

	// Check if at a sensor and move appropriately, if a cold boot guess direction as forward.

	ReadSensors(addr);
	if (addr[4]==1)
	{
		dir = 0x00;	//Select forward.
		start = 0;
	}
	else 
	{
		dir = 0x80;
		start =1;	//Select reverse.
	}

	// Find the nearest sensor and decide where to go from there.

	printf("\n\nMoving saw carriage to Zero point, Please Wait!\n\n");

	while (!Sensor(addr))(ClockParallelPort(4,1,dir,addr));	// Go to nearest available sensor.
	if (addr[4]>2) dir = 0x80;	//Select reverse.
	else dir =0x00;				//Select forward if below start point (Sensor 2).

	while ((!Sensor(addr))|(addr[4]!=2))(ClockParallelPort(4,1,dir,addr)); // Go to Sensor 2.

	// Always ensure that the carriage stops at the high side of zero point sensor.
	
	while (Sensor(addr))(ClockParallelPort(4,1,0x00,addr));
	ClockParallelPort(440,1,0x00,addr);	// Move about 1mm clear and then nudge back to sensor.
	while (!Sensor(addr))(ClockParallelPort(4,3,0x80,addr));

	return;
}


bool Sensor(int addr[])

	//Read the sensor byte and set flag if a sensor is active
{
	bool True = 1, False = 0, Sens1 = False;
	int sens;

	sens = ReadSensors(addr);

	if (sens > 0)
	{
		Sens1 = True;
	}
	else
		Sens1 = False;

	return Sens1;
}


int ReadSensors(int addr[])

/* Read the status of the optical position sensors via the parallel port status register.
Note, sensors 4 and 5 are multiplexed into bit S7 (which is inverted by the PC) as only 5 input
bits are available, these two sensors are demultiplexed using bit D4 of the output port
Hi = Sensor 4, Lo = Sensor 5.
*/
{
	int Sens, Sens1, SelSens4;
	
	SelSens4=0x10;

	addr[3]=addr[3]|SelSens4;
	
	Out32(addr[0],addr[3]);
	Sens = Inp32(addr[1]);

/*	Invert, mask out junk bits then 3 right shifts to move sensors to their correct binary position.
	NB. Also correct bit 7 which is inverted by the PC.
*/

	Sens = Sens^0x7f;	// Invert all bits except bit 7 which is inverted by the PC as the sensor inputs are active Lo.
	Sens = Sens>>3;	// Right shift required info into the correct binary location.

//Now read in sensor 5

	addr[3]=addr[3]^SelSens4;
	Out32(addr[0],addr[3]);
	Sens1 = Inp32(addr[1]);

	Sens1 = Sens1&0x80;	// Note Bit S7 is already inverted
	Sens1 = Sens1>>2;	// Put the required bit into bit 5 of Sens variable.
	Sens = Sens|Sens1;	// Combine it with the rest of the bits.
	if (Sens>0) addr[4] = Sens;		// Store last detected sensor position in the common array.


	return Sens;
}

float GetLeadScrewPitch()
	//Read in calibration file data.
{
	float pitch;
	int pnter=0;
	char letter, *string;
	FILE *fptr;

	string=(char*)malloc(10);
	strset(string,'0');

	if((fptr=fopen("FretCalFile.cal","r")) == NULL)
	{
		printf("Calibration file cannot be opened\n");	//Whoops!
		while (!kbhit());
		exit(1);
	}

	while ((letter !=EOF) && (letter !='\n'))
	{
		letter=getc(fptr);

		if (letter != '\n')
		{
			string[pnter]=letter;
			pnter=pnter+1;
		}
	}

	fclose(fptr);
	pitch=atof(string);

	return pitch;
}

 

[Lucifre]

Re: C++ Questions

Thank you for all your help DrBob. I have inpout32.dll in my windows/system32 directory, but i heard that i need to register this dll.
When i do that, with regsvr32 it gives me an error DllRegisterServer no entry point was found, and i can't find the fix for it... so i guess i won't be interfacing the port afterall.
I also heard about accessing parallel port with windows API functions, does anyone have info on that?

 

[DrBob13]

Re: C++ Questions

Hi,
I did not find that I needed to register the dll like you said and it worked fine, all I found necessary was to include the lines in the code shown in the quote to show the program that the dll exists, it will then call it as a far call when it needs it to get or put out data. Just send the data to Out32(parallel port address, 'your data') or read as 'your data' = Inp32(parallel port address). the standard address used by a PC for the parallel port LPT1 is 0378h,v which is sent to the dll as 0x0378.

/* ----Prototypes of Inp and Outp--- */

short _stdcall Inp32(short PortAddress);
void _stdcall Out32(short PortAddress, short data);

/* Please Note: This function requires InpOut32.dll to be loaded in the Windows System Directory.
(See Logix4u website for the dll, its coding and usage */
/*--------------------------------*/

I hope that helps.
Bob.

 

[Lucifre]

Re: C++ Questions

Thanx a lot... That's all i needed to know. More i do online reseach more crap i come across.