我正在开发一个具有 GSM 模块的项目，它还与计算机进行串行通信。
我在 Visual Studio 2010 上用 C 语言编写了一个代码来串行传输和接收数据。
代码如下： -
#include "stdafx.h"
#include <windows.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <commdlg.h>
int nread,nwrite;
int main()
{
COMMTIMEOUTS timeouts;
COMMCONFIG dcbSerialParams;
char *words, *buffRead, *buffWrite;
DWORD dwBytesWritten,dwBytesRead;
HANDLE hSerial= CreateFile(L"COM1", GENERIC_READ | GENERIC_WRITE,
0,0,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,0);
if ( hSerial == INVALID_HANDLE_VALUE)
{
if (GetLastError() == ERROR_FILE_NOT_FOUND)
{
printf(" serial port does not exist \n");
}
printf(" some other error occured. Inform user.\n");
}
//DCB dcbSerialParams ;
//GetCommState( hSerial, &dcbSerialParams.dcb);
if (!GetCommState(hSerial, &dcbSerialParams.dcb))
{
printf("error getting state \n");
}
dcbSerialParams.dcb.DCBlength = sizeof(dcbSerialParams.dcb);
dcbSerialParams.dcb.BaudRate = CBR_9600;
dcbSerialParams.dcb.ByteSize = 8;
dcbSerialParams.dcb.StopBits = ONESTOPBIT;
dcbSerialParams.dcb.Parity = NOPARITY;
dcbSerialParams.dcb.fBinary = TRUE;
dcbSerialParams.dcb.fDtrControl = DTR_CONTROL_DISABLE;
dcbSerialParams.dcb.fRtsControl = RTS_CONTROL_DISABLE;
dcbSerialParams.dcb.fOutxCtsFlow = FALSE;
dcbSerialParams.dcb.fOutxDsrFlow = FALSE;
dcbSerialParams.dcb.fDsrSensitivity= FALSE;
dcbSerialParams.dcb.fAbortOnError = TRUE;
if (!SetCommState(hSerial, &dcbSerialParams.dcb))
{
printf(" error setting serial port state \n");
}
GetCommTimeouts(hSerial,&timeouts);
//COMMTIMEOUTS timeouts = {0};
timeouts.ReadIntervalTimeout = 1000;
timeouts.ReadTotalTimeoutConstant = 1000;
timeouts.ReadTotalTimeoutMultiplier = 1000;
timeouts.WriteTotalTimeoutConstant = 1000;
timeouts.WriteTotalTimeoutMultiplier= 1000;
if(!SetCommTimeouts(hSerial, &timeouts))
{
printf("error setting port state \n");
}
while(1)
{
//****************Write Operation*********************//
char data_tx[]="at\r";
words=&data_tx[0];
nwrite = strlen(words);
buffWrite = words;
dwBytesWritten = 0;
if (!WriteFile(hSerial, buffWrite, nwrite, &dwBytesWritten, NULL))
{
printf("error writing to output buffer \n");
}
printf("Data written to write buffer is\n %s \n",buffWrite);
//***************Read Operation******************//
dwBytesRead = 0;
nread = strlen(words);
buffRead = new char[nread +1];
memset(buffRead, 0, nread+1); // ensure that string will be null-terminated
if (!ReadFile(hSerial, buffRead, nread, &dwBytesRead, NULL))
{
printf("error reading from input buffer \n");
}
printf("Data read from read buffer is \n %s \n ",buffRead);
Sleep(10000);
}
CloseHandle(hSerial);
}
当命令“at\r”从计算机传输到 GSM 模块时，它接收到它应该通过发送OK来响应它。
现在我只得到O。如果我再次发送"at\r"我会得到K。
我已经在超级终端上验证了它的 GSM 模块工作正常。如果我发送“at”并输入它，它会以OK响应。
此外，我已经在其他程序上验证了我的 C 代码，它工作正常。
我想知道为什么它不能与 GSM 模块一起正常工作。