Help writing a simple Ymodem Send
 

Hey there, I'm fairly new to programming but have been tasked with writing a Ymodem send program to send some data that I parsed out to hardware. So far I have parsed data into a char array, and then opened up a serial port. I just don't know where to begin in writing a Ymodem send program (the receiving end was written by someone else). Here is my code for opening the serial port, now I am stuck in implementing the actual Ymodem protocol. I have searched for code online but most of it makes use of extra libraries that I don't have. I am currently writing this in Visual C++ . Any help would be greatly appreciated, Thanks!

#include "stdafx.h"

#include "windows.h"

#include "string.h"

#include "stdio.h"

#include "ymodem.h"





HANDLE hComPort;

BOOL SetCommDefaults(HANDLE hSerial);



int main()

{

        hComPort = CreateFile("\\\\.\\COM24", GENERIC_READ | GENERIC_WRITE, 0, 0, OPEN_EXISTING, 0, 0);

        if (hComPort == INVALID_HANDLE_VALUE){

                        return FALSE;

                        SetCommDefaults(hComPort);

                        printf("E012_Failed to open port");

        }else{



        SetCommDefaults(hComPort);

        

        DWORD dwBytesRead =0;

        DWORD dwBytesWritten =1;



        char buf[50];



                sprintf(buf,"I am connected to hyperterminal\n");



                WriteFile(hComPort, buf, strlen(buf), &dwBytesWritten,NULL);

        }



                CloseHandle(hComPort);



                return 0;

}





BOOL SetCommDefaults(HANDLE hComPort)

{

        DCB dcb;

        dcb.BaudRate = 115200;

        dcb.ByteSize = 8;

        dcb.Parity = 0;

        dcb.StopBits = ONESTOPBIT;

        dcb.fDtrControl = DTR_CONTROL_DISABLE;

        dcb.fDtrControl = RTS_CONTROL_DISABLE;

        

        if(!SetCommState(hComPort, &dcb))

                return FALSE;

        return TRUE;

}