Здравствуйте All!
При чтении с ком порта к байту впереди добавляются "лишние" байты FFFFFF, из-за чего это происходит?
| Код |
#include <stdio.h>
#include <windows.h>
HANDLE hComm;
bool Status;
void main()
{
DCB dcbSerialParams = { 0 }; // Initializing DCB structure
dcbSerialParams.DCBlength = sizeof(dcbSerialParams);
Status = GetCommState(hComm, &dcbSerialParams);
dcbSerialParams.BaudRate = CBR_9600; // Setting BaudRate = 9600
dcbSerialParams.ByteSize = 8; // Setting ByteSize = 8
dcbSerialParams.StopBits = ONESTOPBIT;// Setting StopBits = 1
dcbSerialParams.Parity = NOPARITY; // Setting Parity = None
SetCommState(hComm, &dcbSerialParams);
COMMTIMEOUTS timeouts = { 0 };
timeouts.ReadIntervalTimeout = 50; // in milliseconds
timeouts.ReadTotalTimeoutConstant = 50; // in milliseconds
timeouts.ReadTotalTimeoutMultiplier = 10; // in milliseconds
timeouts.WriteTotalTimeoutConstant = 50; // in milliseconds
timeouts.WriteTotalTimeoutMultiplier = 10; // in milliseconds
hComm = CreateFile("\\\\.\\COM4", //port name
GENERIC_READ | GENERIC_WRITE, //Read/Write
0, // No Sharing
NULL, // No Security
OPEN_EXISTING,// Open existing port only
0, // Non Overlapped I/O
NULL); // Null for Comm Devices
if (hComm == INVALID_HANDLE_VALUE)
printf("Error in opening serial port\n");
else
printf("opening serial port successful\n");
char lpBuffer[] = {0xAA,0x23,0x43,0x27,0x86,0x55};
DWORD dNoOFBytestoWrite; // No of bytes to write into the port
DWORD dNoOfBytesWritten = 0; // No of bytes written to the port
dNoOFBytestoWrite = sizeof(lpBuffer);
Status = WriteFile(hComm, // Handle to the Serial port
lpBuffer, // Data to be written to the port
dNoOFBytestoWrite, //No of bytes to write
&dNoOfBytesWritten, //Bytes written
NULL);
Status = SetCommMask(hComm, EV_RXCHAR);
DWORD dwEventMask;
Status = WaitCommEvent(hComm, &dwEventMask, NULL);
char TempChar; //Temporary character used for reading
char SerialBuffer[256];//Buffer for storing Rxed Data
DWORD NoBytesRead;
int i = 0;
do
{
ReadFile( hComm, //Handle of the Serial port
&TempChar, //Temporary character
sizeof(TempChar),//Size of TempChar
&NoBytesRead, //Number of bytes read
NULL);
SerialBuffer[i] = TempChar;// Store Tempchar into buffer
printf("%02x", SerialBuffer[i]);// здесь выводит на консоль то что описал выше
system("pause");
i++;
}
while (NoBytesRead > 0);
CloseHandle(hComm);//Closing the Serial Port
system("pause");
}
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Пример ответа:
90
FFFFFF43
76
FFFFFF32
88
FFFFFF29
Причём ответ с порта правильный, если бы не добавляемые FFFFFF.
Прошу Вашей помощи.
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