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/*      This file is part of MoteCtrl

        http://www.mikrokopter.de/ucwiki/en/MoteCtrl

*/

//Include header files, which provide resources, pc_serial_port.c needs:

#include <windows.h>    //Windows API, to interface with the serial port

#include <stdio.h>              //Standard I/O (printf for instance)

#include "pc_serial_port.h"

/*

Compiler & Linker Porperties:

Set "Character Set"-CompilerFlag to "Not Set" or "Multi Byte Character Set" to

avoid Errors about Windows API functions that can handle Unicode paramters.

In Visual Studio: Properties of Project -> Configuration Properties -> General

*/

HANDLE hCom;    //Handle, which contains inf about the opened Device File

                                //(the opened COM-Port, returned by CreateFile function)

//Initialize & Configure COMx-Port

//return value: EXIT_FAILURE=1, EXIT_SUCCESS=0 (stdlib macros)

int init_com_port(int comNumber) {

        DCB dcb;                //Device Control Block, contains Configuration for COM-Port

        char comPort[5] = {'C','O','M'}; //Number and String Terminator to be added

        int fSuccess;   //Stores inf about file-actions (action succeeded or failed)

        COMMTIMEOUTS timeouts;  //Struct, which stores inf about the timeout

                                                        //behaviour of the COM-Port

        //Get the Com-Port Number:

        comPort[3] = 48 + comNumber;    //COMx (x is ASCII coded)

        comPort[4] = 0;                                 //add string Terminator 'NUL'

        //Create Device File, initialize serial Port:

        hCom = CreateFile( comPort,     //open COMx Device (pointer to comPort-String)

                                        GENERIC_READ | GENERIC_WRITE,   //write/read permisions

                                        0,    // must be opened with exclusive-access

                                        NULL, // default security

                                        OPEN_EXISTING, // must use OPEN_EXISTING

                                        0,    // no overlapping

                                        NULL  // hTemplate must be NULL for comm devices

                                        );

        //Check, if CreateFile succeeded:

        if (hCom == INVALID_HANDLE_VALUE) {

                printf ("***ERR: CreateFile failed with error %d.\n", GetLastError());

                return EXIT_FAILURE;

        }

        //Get the currently active Device Control Block (DCB) for the COMx:

        SecureZeroMemory(&dcb, sizeof(DCB)); //initialize entire dcb-struct with zeros

        dcb.DCBlength = sizeof(DCB);                   

        fSuccess = GetCommState(hCom, &dcb); //write the current configuration to

                                                                                 //our dcb-struct

        //GetCommState returns 0, if error occured while getting the DCB

        if (!fSuccess) {

                printf ("***ERR: GetCommState failed with error %d.\n", GetLastError());

                return EXIT_FAILURE;

        }

        /*Change the values of the obtained dcb-struct to match the config of the

         *Mikrokopter. Currently the FlightControl communicates at:

         *57600 Baud (bps), 8 Data bits, no parity bit, 1 stop bit */

        dcb.BaudRate = CBR_57600;     // Set Baudrate

        dcb.ByteSize = 8;             // data size, transmit and receive

        dcb.Parity = NOPARITY;        // no parity bit

        dcb.StopBits = ONESTOPBIT;    // one stop bit

        //Send reconfigured dcb back to COMx Device-File:

        fSuccess = SetCommState(hCom, &dcb);

        //SetCommState returns a 0, if error occured while setting the DCB for COMx

        if (!fSuccess) {

                printf ("***ERR: SetCommState failed with error %d.\n", GetLastError());

      return EXIT_FAILURE;

        }

        //Configure the Read-Timeout behaviour of the initialized COMx-Port:

        /* The following Read-Timeout config determines the behaviour of the

        ReadFile cmd (applied to the initialized COMx-Port):

        If a Byte is in the Hardware UART-Buffer of the initialized COM-Port and

        the ReadFile function is called, this byte is read. If theres no byte in

        the UART-InputBuffer and the ReadFile function is called, the ReadFile

        function will return *immediatly* (BytesRead parameter is zero then).

        */

        timeouts.ReadIntervalTimeout            = MAXDWORD;

        timeouts.ReadTotalTimeoutMultiplier = 0;

        timeouts.ReadTotalTimeoutConstant       = 0;

        //Send the Timeout-Config to the COM-Port:

        fSuccess = SetCommTimeouts (hCom, &timeouts);

        //Check, if setting the timeout-settings was successfull:

        if(!fSuccess) {

                printf("***ERR: SetCommTimeouts failed with error %d.\n", GetLastError());

                return EXIT_FAILURE;

        }

        //Initialization & Configuration of COMx done!

        return EXIT_SUCCESS;

}

//Function which reads 1 Byte of the Rx-Buffer of the initialized COM-Port:

//Return value: Number of the bytes read (should be 0 or 1)

int getCharFromCom (char* inputBuffer) {

        int numOfBytesRead;

        ReadFile (hCom, inputBuffer, 1, &numOfBytesRead, NULL);

        //read char is stored in the passed char-buffer

        return numOfBytesRead;

}

//Function which writes [length] Byte to the Tx-Buffer of the initialized COM-Port:

//Returns something>0 if write failed, 0 if successfull

int sendStringToCom (char* toSend, int length) {

        int numOfBytesWritten;

        //write char to which the passed char-pointer points to

        return WriteFile (hCom, toSend, length, &numOfBytesWritten, NULL);

}