comtstd.c

一个关于Com端口调制的程序。包括向Com端口发送数据及从Com端口接受数据两部分。

#include <windows.h>
#include <stdio.h>

#define NUM     128
#define TEST_COM "COM1"

DWORD main(int argc, char *argv[], char *envp[])
{
    CHAR chBuffer[128];
    CHAR RdBuffer[128];
    DWORD UseBaud = 9600;
    WORD i;
    HANDLE hCommPort;
    DCB    dcb;
    BOOL   bRc;
    DWORD  dwNumWritten,dwNumRead,dwErrors;
    
    envp;
    
    if (argc > 1)
    {
        sscanf(argv[1],"%d",&UseBaud);
    }
    
    
    printf("\n\n *** COMM TEST START ***\n\n");
    
    printf("Opening the comm port for read write\n");
    
    hCommPort = CreateFile(
        TEST_COM,
        GENERIC_READ|GENERIC_WRITE,
        0, // exclusive
        NULL, // sec attr
        OPEN_EXISTING,
        0,             // no attributes
        NULL);         // no template
    
    if (hCommPort == (HANDLE)-1)
    {
        printf("FAIL: OpenComm failed rc: %lx\n",hCommPort);
        return -1;
    }
    
    
    printf("Opening the comm port for read write: SUCCESS hCommPort=%lx\n",hCommPort);
    
    printf("Setting the line characteristics 9600,8,N,1 on comm \n");
    
    dcb.DCBlength   = sizeof(DCB);
    // dcb.DCBversion  = 0x0002; BUG BUG in spec not in header
    
    
    if (!GetCommState(hCommPort,&dcb))
    {
        printf("FAIL: Couldn't get the dcb: %d\n",GetLastError());
        return FALSE;
    }
    
    dcb.BaudRate = UseBaud;
    
    dcb.ByteSize = 8;
    dcb.Parity   = NOPARITY;
    dcb.StopBits = ONESTOPBIT;
    
    bRc = SetCommState(hCommPort,&dcb);
    
    if (!bRc)
    {
        printf("FAIL: cannot set the comm state rc:%lx\n",bRc);
        return -1;
    }
    
    printf("Setting the line characteristics 9600,8,N,1 on comm: SUCCESS\n");
    
    
    printf("Filling the buffer with the known chars \n");
    
    for (i=0; i< NUM; i++)
    {
        //chBuffer[i] = 'a';
        chBuffer[i] = (CHAR)i;
        
    }
    
    printf("Filling the buffer with the known chars : SUCCESS\n");
    
    printf("Dumping the buffer before sending it to comm\n");
    
    for (i=0; i< NUM; i++)
    {
        //printf("%c",RdBuffer[i]);
        printf(" %d ",chBuffer[i]);
        
    }
    
    printf("\nDumping the buffer before sending it to comm SUCCESS\n");
    
    
    
    printf("Filling the Rdbuffer with the known chars (0xFF) to makeit dirty\n");
    
    for (i=0; i< NUM; i++)
    {
        RdBuffer[i] = 'o';
    }
    
    printf("Filling the Rdbuffer with the known chars (0xFF): SUCCESS\n");
    
    printf("Writting this buffer to the comm port\n");
    
    bRc = WriteFile( hCommPort,
        chBuffer,
        NUM,
        &dwNumWritten,
        NULL);
    
    if (!bRc)
    {
        printf("FAIL: cannot Write To the comm port:%lx\n",bRc);
        return -1;
    }
    
    printf("Writting this buffer to the comm port: SUCCESS rc:%lx, byteswritten:%lx\n",
        bRc,dwNumWritten);
    
    
    printf("Reading this buffer from the comm port\n");

    memset(RdBuffer, 0, NUM);
    
    bRc = ReadFile( hCommPort,
        RdBuffer,
        NUM,
        &dwNumRead,
        NULL);
    
    if (!bRc)
    {
        printf("FAIL: cannot Read From the comm port:%lx\n",bRc);
        return -1;
    }
    
    printf("Reading this buffer from the comm port: SUCCESS rc:%lx, bytesread:%lx\n",
        bRc,dwNumRead);
    
    
    printf("Dumping the Rdbuffer with the comm data\n");
    
    for (i=0; i< dwNumRead; i++)
    {
        //printf("%c",RdBuffer[i]);
        printf(" %d ",RdBuffer[i]);
        
    }
    
    printf("\nDumping the Rdbuffer with the comm data: SUCCESS\n");
    
    
    printf("Closing the comm port\n");
    
    
    bRc = ClearCommError(hCommPort,&dwErrors,NULL);
    
    printf("ClearCommError: rc= %lx and dwErrors=%lx\n",bRc,dwErrors);
    
    
    bRc = CloseHandle(hCommPort);
    
    if (!bRc)
    {
        printf("FAIL: cannot close the comm port:%lx\n",bRc);
        return -1;
    }
    
    
    printf("\n\n*** COMM TEST OVER*** \n\n");
    return 0;
}