Advantech PCL-740 Spezifikationen PDF herunterladen (Seite 24)

Appendix A Register structure and format 21

Programming example

The following C example shows how to program the PCL-740's

registers directly. It uses I/O ports hex 3F8 and 2F8 to test the PCL-

740’s send, receive and FIFO functions.

/**************************************************/

/* Program: DEMO01.C */

/* Description: */

/* Sends a string from COM1 to COM2 then reads */

/* it back from COM2 and displays it on the */

/* screen. It uses direct register control. */

/**************************************************/

#include <dos.h>

#include <io.h>

#include <stdio.h>

#include <conio.h>

/* Timeout value in seconds */

#define TIME_OUT 10000

static int base0=0x3f8; /* Port 1 base address (COM1) */

static int base1=0x2f8; /* Port 2 base address (COM2) */

static char rec[16]; /* Receive buffer */

static char cmd[16]; /* Command buffer */

void main()

{

int i;

timeout; /* counter for timeout */

char flag;

/* Set up Port 1 (COM1) */

outport((base0+2),0xc9); /* Enable FIFO */

outp(base0+3,0x80); /* Set DLAB=1 */

/* Set bps = 115200 */

outp(base0 ,0x01); outp(base0+1,0x00);

outp(base0+3,0x03); /* set data=8; stop=1; no parity*/

outp(base0+1,0x00); /* disable interrupt */

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Advantech PCL-740 Spezifikationen Seite 24