Does anyone know how I could send an ascii through the parralel port to emulate a keyboard response in eprime? I have an experiment that needs to interact with an external device using keypress responses. Therefore I need to mimick them using code in the eprime presentation in a way which is timelocked to events (stimulus presentation). Any suggestions? I have tried so many things I cant really tell if it's my hardware or software that isnt working at this point
Hello,
Check your connections and verify that your port is correctly grounded. If this is done on an old computer, the output can be easily addressed to location 0x378 of the system, if I were using the old Borland C approach I think it would be:
#include"conio.h"
#include"dos.h"
#define PORT 0x378
void main()
{
while(!kbhit())
{
outportb(PORT, ~inportb(PORT) );
delay(1000);
}
}
For reading I think it is necessary to use 0x379(note that MSB is inverted):
#include"stdio.h"
#include"conio.h"
#include"dos.h"
#define PORT 0x378
void main()
{
int data;
clrscr();
while(!kbhit())
{
data=inportb(PORT+1);
gotoxy(3,10);
printf("Data available in status register: %3d (decimal), %3X (hex)\n", data, data);
printf("\n Pin 15: %d",(data & 0x08)/0x08);
printf("\n Pin 13: %d",(data & 0x10)/0x10);
printf("\n Pin 12: %d",(data & 0x20)/0x20);
printf("\n Pin 11: %d",(data & 0x80)/0x80);
printf("\n Pin 10: %d",(data & 0x40)/0x40);
delay(10);
}
}
Newer systems blocked out the option to do so, therefore use of some software tools like Winport (Windows XP) were required to enable communication. I am afraid I dont know how to operate with Win7 or newer. For Linux/Unix, I think the way of performing these operations is likewise (POSIX):
#include
I hope that this was helpful.
You can also check these sites:
http://electrosofts.com/parallel/
https://www.howtoforge.com/tutorial/accessing-parallel-ports-on-linux/
A simple way to write to the port can be done with a code similar to the one below. It is not tested, since I do not have a computer with a parallel port, but you will get the idea from the source.
#include
#include
#include
#define DATA 0x378
#define STATUS DATA+1
#define CONTROL DATA+2
int main(void) {
int M = 0b01001101;
int send = 0x08;
if (ioperm(DATA, 3, 1)) {
printf("Cannot open port!\n");
return -1;
}
// Send the binary ASCII of the letter M (01001101) to the port
outb(DATA, M);
outb(CONTROL, send^0x0b);
return 0;
}
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