在c

Question

我遇到串口连接时最不寻常的问题。

我正在尝试从rs-232设备解析一些数据，但如果我用我的程序打开串口，数据总是会出现乱码。

我发送了一个示例，当我嗅探程序打开的连接时，我看到了什么：

我在Realterm打开连接时看到的内容：

我在两种情况下都使用完全相同的配置打开串行连接：baud = 9600,8个数据位，无奇偶校验，1个停止位。所有相同的，并由嗅探器认证。

我已经关注了有关串行连接的MSDN文章，确定了重叠连接，查找了串行事件以及所有...我在这里发布了我使用的代码：

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

Serconfig serconfig;

int seropen()
{
    serconfig.hserial = CreateFile( serconfig.port,  
                    GENERIC_READ | GENERIC_WRITE, 
                    0, 
                    0, 
                    OPEN_EXISTING,
                    FILE_FLAG_OVERLAPPED,
                    0); //abre
    if (serconfig.hserial == INVALID_HANDLE_VALUE) //se der erro, sai fora
    {
        printf("erro ao abrir %s\r\n", serconfig.port);
        return -1;
    }

   FillMemory(&(serconfig.dcbSerialParams), sizeof(DCB), 0);
   serconfig.dcbSerialParams.DCBlength = sizeof(DCB);
/*   
   if (!BuildCommDCB(serconfig.dcbstring, &(serconfig.dcbSerialParams))) {   
      printf("%s não está pronta\r\n", serconfig.port);
      serclose();
      return -1;
   }
*/

  if( !GetCommState(serconfig.hserial, &(serconfig.dcbSerialParams)) ) // Obtém a configuração atual da Porta Serial.
     return false;  // Erro na leitura de DCB.

   //Define novos parâmetros
   serconfig.dcbSerialParams.BaudRate = CBR_9600; 
   serconfig.dcbSerialParams.ByteSize = 8;
   serconfig.dcbSerialParams.Parity = NOPARITY;
   serconfig.dcbSerialParams.StopBits = ONESTOPBIT; 

   if (!SetCommState(serconfig.hserial, &serconfig.dcbSerialParams))
   {
      int error = GetLastError();
      printf("configuração de %s invalida. Erro %d\r\n", serconfig.port, error);
      serclose();  
      return -1;    
   }
   /*
   COMMTIMEOUTS timeouts;

   timeouts.ReadIntervalTimeout = 20; 
   timeouts.ReadTotalTimeoutMultiplier = 10;
   timeouts.ReadTotalTimeoutConstant = 100;
   timeouts.WriteTotalTimeoutMultiplier = 10;
   timeouts.WriteTotalTimeoutConstant = 100;

   if (!SetCommTimeouts(serconfig.hserial, &timeouts)){
      printf("erro ao configurar os timeouts de %s", serconfig.port);
      return -1;
   }
   */
   serconfig.osReader = {0};

   PurgeComm(serconfig.hserial, PURGE_RXCLEAR|PURGE_RXABORT);
   printf("%s aberta e configurada\r\n", serconfig.port);
   return 0;
}

int serclose()
{
    CloseHandle(serconfig.hserial); // se der erro,sai fora
    CloseHandle(serconfig.osReader.hEvent); // se der erro,sai fora
}


void serread(char * buffer, long long unsigned int * result, int read) // fiz deste jeito para ter compatibilidade com a macro SERIAL_INPUT
{
    DWORD dwRead;

    // Create the overlapped event. Must be closed before exiting
    // to avoid a handle leak.

    if (!serconfig.fWaitingOnRead) 
    {
        serconfig.osReader.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
        if (serconfig.osReader.hEvent == NULL)
        {
            printf("erro criando evento\r\n");
            CloseHandle(serconfig.osReader.hEvent); // se der erro,sai fora
            *result = 0;
            return;
            // Error creating overlapped event; abort.
        }
        // Issue read operation.
        //printf("tentando ler %d bytes\r\n", read);
        if (!ReadFile(serconfig.hserial, buffer, read, &dwRead, &serconfig.osReader)) 
        {
            if (GetLastError() != ERROR_IO_PENDING)     // read not delayed?
            {
                printf("erro de comunicação\r\n");
                CloseHandle(serconfig.osReader.hEvent); // se der erro,sai fora
                *result = 0  ;              
            }   
            else
            {
                //printf("leitura incompleta\r\n", dwRead); 
                serconfig.fWaitingOnRead = TRUE;
                *result = 0  ; 
                return;
            }
        }
        else 
        {   //printf("lidos %d bytes\r\n", dwRead); 
            // read completed immediately
            //HandleASuccessfulRead(lpBuf, dwRead);
            //PurgeComm(serconfig.hserial, PURGE_RXCLEAR|PURGE_RXABORT);
            *result = dwRead;
            serconfig.lastread = dwRead;
            CloseHandle(serconfig.osReader.hEvent); 
            PurgeComm(serconfig.hserial, PURGE_RXCLEAR|PURGE_RXABORT);
            return;
        }
    }

    if (serconfig.fWaitingOnRead) {
        //printf("aguardando evento\r\n");
        DWORD dwRes = WaitForSingleObject(serconfig.osReader.hEvent, READ_TIMEOUT);
        switch(dwRes)
        {
            // Read completed.
            //printf("leitura completa "); 
            case WAIT_OBJECT_0:
                if (!GetOverlappedResult(serconfig.hserial, &serconfig.osReader, &dwRead, FALSE))
                {
                    // Error in communications; report it.
                    CloseHandle(serconfig.osReader.hEvent); // se der erro,sai fora
                    printf("erro de comunicação\r\n");
                    serconfig.fWaitingOnRead = FALSE;
                    *result = 0; 
                }
                else
                    // Read completed successfully.
                    //HandleASuccessfulRead(lpBuf, dwRead);
                    *result = dwRead;
                    serconfig.fWaitingOnRead = FALSE;
                    serconfig.lastread = dwRead;
                    //printf("lidos %d bytes\r\n", dwRead); 
                    CloseHandle(serconfig.osReader.hEvent); 
                    PurgeComm(serconfig.hserial, PURGE_RXCLEAR|PURGE_RXABORT);
                    return;
                    //  Reset flag so that another opertion can be issued.
                break;

            case WAIT_TIMEOUT:
                //printf("timeout\r\n");
                // Operation isn't complete yet. fWaitingOnRead flag isn't
                // changed since I'll loop back around, and I don't want
                // to issue another read until the first one finishes.
                //
                // This is a good time to do some background work.
                *result = 0; 
                break;                       

            default:
                // Error in the WaitForSingleObject; abort.
                // This indicates a problem with the OVERLAPPED structure's
                // event handle.
                *result = 0;
                serconfig.fWaitingOnRead = FALSE;
                printf("erro na comunicação\r\n");
                break;
        }
    }
}