Question

I tried the Serial.cpp code from Arduino’s website.

I just made a couple of changes and got the code working properly. However, the issue is, the C++ code serially sends in ASCII values and not integers. For example, if I send in “5” I receive 53 at the receiver side.

I tried changing the buffer type to an int instead of a char, but it returned an error saying:

error C2664: ‘ReadFile’ : cannot convert parameter 2 from ‘int’ to ‘LPVOID’

Is there a way to send integers instead of ASCII values serially?

Below is a snippet of the code.

bool Serial::WriteData(char *buffer, unsigned int nbChar)
{
    DWORD bytesSend;

    //Try to write the buffer on the Serial port
    if (!WriteFile(this->hSerial, (void *)buffer, nbChar, &bytesSend, 0))
    {
        //In case it don't work get comm error and return false
        ClearCommError(this->hSerial, &this->errors, &this->status);

        return false;
    }
    else
        return true;
}


int main() {
    // Convert from char* to wchar*

    char *name_ser="COM7";
    cout << name_ser << "(char*)" << endl;
    size_t origsize=strlen(name_ser)+1;
    const size_t newsize=100;
    size_t convertedChars=0;
    wchar_t wcstring[newsize];
    mbstowcs_s(&convertedChars, wcstring, origsize, name_ser, _TRUNCATE);
    wcscat_s(wcstring, L"(wchar_t*)");
    wcout<<wcstring<<endl;

    Serial serial(wcstring);

    if (serial.IsConnected()){
        while (1){
            char *chr0 = "5";
            serial.WriteData(chr0,1);
            cout<<chr0<<endl;
        }
    }
    system("pause");
    return 0;
}

Answer 1

You’ll probably need to change the method signature. Try something like this:

bool Serial::WriteData(int * buffer, unsigned int length)
{
    DWORD bytesSend;
    if(!WriteFile(this->hSerial, (void *)buffer, length*sizeof(int), &bytesSend, 0))
    {
        ClearCommError(this->hSerial, &this->errors, &this->status);
        return false;
    }
    else
        return true;
}

You’ll need to reconstitute the integers on the Arduino: ints are typically 4 bytes, and I expect the Arduino receive routines are expecting ASCII by default.