Subversion Repositories FlightCtrl

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Copyright (c) 04.2007 Holger Buss
// + Nur für den privaten Gebrauch
// + www.MikroKopter.com
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Es gilt für das gesamte Projekt (Hardware, Software, Binärfiles, Sourcecode und Dokumentation),
// + dass eine Nutzung (auch auszugsweise) nur für den privaten und nicht-kommerziellen Gebrauch zulässig ist.
// + Sollten direkte oder indirekte kommerzielle Absichten verfolgt werden, ist mit uns (info@mikrokopter.de) Kontakt
// + bzgl. der Nutzungsbedingungen aufzunehmen.
// + Eine kommerzielle Nutzung ist z.B.Verkauf von MikroKoptern, Bestückung und Verkauf von Platinen oder Bausätzen,
// + Verkauf von Luftbildaufnahmen, usw.
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Werden Teile des Quellcodes (mit oder ohne Modifikation) weiterverwendet oder veröffentlicht,
// + unterliegen sie auch diesen Nutzungsbedingungen und diese Nutzungsbedingungen incl. Copyright müssen dann beiliegen
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Sollte die Software (auch auszugesweise) oder sonstige Informationen des MikroKopter-Projekts
// + auf anderen Webseiten oder Medien veröffentlicht werden, muss unsere Webseite "http://www.mikrokopter.de"
// + eindeutig als Ursprung verlinkt und genannt werden
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Keine Gewähr auf Fehlerfreiheit, Vollständigkeit oder Funktion
// + Benutzung auf eigene Gefahr
// + Wir übernehmen keinerlei Haftung für direkte oder indirekte Personen- oder Sachschäden
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Die Portierung der Software (oder Teile davon) auf andere Systeme (ausser der Hardware von www.mikrokopter.de) ist nur
// + mit unserer Zustimmung zulässig
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Die Funktion printf_P() unterliegt ihrer eigenen Lizenz und ist hiervon nicht betroffen
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Redistributions of source code (with or without modifications) must retain the above copyright notice,
// + this list of conditions and the following disclaimer.
// +   * Neither the name of the copyright holders nor the names of contributors may be used to endorse or promote products derived
// +     from this software without specific prior written permission.
// +   * The use of this project (hardware, software, binary files, sources and documentation) is only permittet
// +     for non-commercial use (directly or indirectly)
// +     Commercial use (for excample: selling of MikroKopters, selling of PCBs, assembly, ...) is only permitted
// +     with our written permission
// +   * If sources or documentations are redistributet on other webpages, out webpage (http://www.MikroKopter.de) must be
// +     clearly linked as origin
// +   * porting to systems other than hardware from www.mikrokopter.de is not allowed
// +  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// +  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// +  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// +  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// +  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// +  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// +  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// +  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// +  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// +  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// +  POSSIBILITY OF SUCH DAMAGE.
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/wdt.h>
#include <avr/pgmspace.h>
#include <stdarg.h>
#include <string.h>

#include "eeprom.h"
#include "menu.h"
#include "timer0.h"
#include "uart0.h"
#include "attitude.h"
#include "rc.h"
#include "externalControl.h"
#include "output.h"

#ifdef USE_MK3MAG
#include "mk3mag.h"
#endif

#define FC_ADDRESS 1
#define NC_ADDRESS 2
#define MK3MAG_ADDRESS 3

#define FALSE   0
#define TRUE    1
//int8_t test __attribute__ ((section (".noinit")));
uint8_t request_VerInfo                 = FALSE;
uint8_t request_ExternalControl         = FALSE;
uint8_t request_Display                 = FALSE;
uint8_t request_Display1                = FALSE;
uint8_t request_DebugData               = FALSE;
uint8_t request_Data3D                  = FALSE;
uint8_t request_DebugLabel              = 255;
uint8_t request_PPMChannels             = FALSE;
uint8_t request_MotorTest               = FALSE;
uint8_t request_variables               = FALSE;

uint8_t DisplayLine = 0;

volatile uint8_t txd_buffer[TXD_BUFFER_LEN];
volatile uint8_t rxd_buffer_locked = FALSE;
volatile uint8_t rxd_buffer[RXD_BUFFER_LEN];
volatile uint8_t txd_complete = TRUE;
volatile uint8_t ReceivedBytes = 0;
volatile uint8_t *pRxData = 0;
volatile uint8_t RxDataLen = 0;

uint8_t motorTestActive  = 0;
uint8_t motorTest[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
uint8_t ConfirmFrame;

typedef struct {
  int16_t Heading;
} __attribute__((packed)) Heading_t;

DebugOut_t              DebugOut;
Data3D_t                Data3D;
UART_VersionInfo_t      UART_VersionInfo;

uint16_t DebugData_Timer;
uint16_t Data3D_Timer;
uint16_t DebugData_Interval = 500; // in 1ms
uint16_t Data3D_Interval = 0; // in 1ms

#ifdef USE_MK3MAG
int16_t Compass_Timer;
#endif

// keep lables in flash to save 512 bytes of sram space
const prog_uint8_t ANALOG_LABEL[32][16] = {
    //1234567890123456
    "AnglePitch      ", //0
    "AngleRoll       ",
    "AngleYaw        ",
    "GyroPitch(PID)  ",
    "GyroRoll(PID)   ",
    "GyroYaw         ", //5
    "GyroPitch(AC)   ",
    "GyroRoll(AC)    ",
    "GyroYaw(AC)     ",
    "AccPitch (angle)",
    "AccRoll (angle) ", //10
    "UBat            ",
    "Pitch Term      ",
    "Roll Term       ",
    "Yaw Term        ",
    "Throttle Term   ", //15
    "0th O Corr pitch",
    "0th O Corr roll ",
    "DriftCompDelta P",
    "DriftCompDelta R",
    "ADPitchGyroOffs ", //20
    "ADRollGyroOffs  ",
    "M1              ",
    "M2              ",
    "M3              ",
    "M4              ", //25
    "ControlYaw      ",
    "Airpress. Range ",
    "DriftCompPitch  ",
    "DriftCompRoll   ",
    "AirpressFiltered", //30
    "AirpressADC     "
  };

/****************************************************************/
/*              Initialization of the USART0                    */
/****************************************************************/
void usart0_Init (void) {
  uint8_t sreg = SREG;
  uint16_t ubrr = (uint16_t) ((uint32_t) SYSCLK/(8 * USART0_BAUD) - 1);
 
  // disable all interrupts before configuration
  cli();
 
  // disable RX-Interrupt
  UCSR0B &= ~(1 << RXCIE0);
  // disable TX-Interrupt
  UCSR0B &= ~(1 << TXCIE0);
 
  // set direction of RXD0 and TXD0 pins
  // set RXD0 (PD0) as an input pin
  PORTD |= (1 << PORTD0);
  DDRD &= ~(1 << DDD0);
  // set TXD0 (PD1) as an output pin
  PORTD |= (1 << PORTD1);
  DDRD |=  (1 << DDD1);
 
  // USART0 Baud Rate Register
  // set clock divider
  UBRR0H = (uint8_t)(ubrr >> 8);
  UBRR0L = (uint8_t)ubrr;
 
  // USART0 Control and Status Register A, B, C
 
  // enable double speed operation in
  UCSR0A |= (1 << U2X0);
  // enable receiver and transmitter in
  UCSR0B = (1 << TXEN0) | (1 << RXEN0);
  // set asynchronous mode
  UCSR0C &= ~(1 << UMSEL01);
  UCSR0C &= ~(1 << UMSEL00);
  // no parity
  UCSR0C &= ~(1 << UPM01);
  UCSR0C &= ~(1 << UPM00);
  // 1 stop bit
  UCSR0C &= ~(1 << USBS0);
  // 8-bit
  UCSR0B &= ~(1 << UCSZ02);
  UCSR0C |=  (1 << UCSZ01);
  UCSR0C |=  (1 << UCSZ00);
 
  // flush receive buffer
  while ( UCSR0A & (1<<RXC0) ) UDR0;
 
  // enable interrupts at the end
  // enable RX-Interrupt
  UCSR0B |= (1 << RXCIE0);
  // enable TX-Interrupt
  UCSR0B |= (1 << TXCIE0);
 
  // initialize the debug timer
  DebugData_Timer = SetDelay(DebugData_Interval);
 
  // unlock rxd_buffer
  rxd_buffer_locked = FALSE;
  pRxData = 0;
  RxDataLen = 0;
 
  // no bytes to send
  txd_complete = TRUE;
 
#ifdef USE_MK3MAG
  Compass_Timer = SetDelay(220);
#endif
 
  UART_VersionInfo.SWMajor = VERSION_MAJOR;
  UART_VersionInfo.SWMinor = VERSION_MINOR;
  UART_VersionInfo.SWPatch = VERSION_PATCH;
  UART_VersionInfo.ProtoMajor = VERSION_SERIAL_MAJOR;
  UART_VersionInfo.ProtoMinor = VERSION_SERIAL_MINOR;
 
  // restore global interrupt flags
  SREG = sreg;
}

/****************************************************************/
/* USART0 transmitter ISR                                       */
/****************************************************************/
ISR(USART0_TX_vect) {
  static uint16_t ptr_txd_buffer = 0;
  uint8_t tmp_tx;
  if(!txd_complete) { // transmission not completed
    ptr_txd_buffer++;                    // die [0] wurde schon gesendet
    tmp_tx = txd_buffer[ptr_txd_buffer];
    // if terminating character or end of txd buffer was reached
    if((tmp_tx == '\r') || (ptr_txd_buffer == TXD_BUFFER_LEN)) {
      ptr_txd_buffer = 0; // reset txd pointer
      txd_complete = 1; // stop transmission
    }
    UDR0 = tmp_tx; // send current byte will trigger this ISR again
  }
  // transmission completed
  else ptr_txd_buffer = 0;
}

/****************************************************************/
/* USART0 receiver               ISR                            */
/****************************************************************/
ISR(USART0_RX_vect) {
  static uint16_t crc;
  static uint8_t ptr_rxd_buffer = 0;
  uint8_t crc1, crc2;
  uint8_t c;

  c = UDR0;  // catch the received byte

  if(rxd_buffer_locked) return; // if rxd buffer is locked immediately return

  // the rxd buffer is unlocked
  if((ptr_rxd_buffer == 0) && (c == '#')) { // if rxd buffer is empty and syncronisation character is received
    rxd_buffer[ptr_rxd_buffer++] = c; // copy 1st byte to buffer
    crc = c; // init crc
  }
#if 0
  else if (ptr_rxd_buffer == 1) { // handle address
    rxd_buffer[ptr_rxd_buffer++] = c; // copy byte to rxd buffer
    crc += c; // update crc
  }
#endif
  else if (ptr_rxd_buffer < RXD_BUFFER_LEN) { // collect incomming bytes
    if(c != '\r') { // no termination character
      rxd_buffer[ptr_rxd_buffer++] = c; // copy byte to rxd buffer
      crc += c; // update crc
    } else { // termination character was received
      // the last 2 bytes are no subject for checksum calculation
      // they are the checksum itself
      crc -= rxd_buffer[ptr_rxd_buffer-2];
      crc -= rxd_buffer[ptr_rxd_buffer-1];
      // calculate checksum from transmitted data
      crc %= 4096;
      crc1 = '=' + crc / 64;
      crc2 = '=' + crc % 64;
      // compare checksum to transmitted checksum bytes
      if((crc1 == rxd_buffer[ptr_rxd_buffer-2]) && (crc2 == rxd_buffer[ptr_rxd_buffer-1])) {
        // checksum valid
        rxd_buffer[ptr_rxd_buffer] = '\r'; // set termination character
        ReceivedBytes = ptr_rxd_buffer + 1;// store number of received bytes
        rxd_buffer_locked = TRUE;          // lock the rxd buffer
        // if 2nd byte is an 'R' enable watchdog that will result in an reset
        if(rxd_buffer[2] == 'R') {wdt_enable(WDTO_250MS);} // Reset-Commando
      } else {  // checksum invalid
        rxd_buffer_locked = FALSE; // unlock rxd buffer
      }
      ptr_rxd_buffer = 0; // reset rxd buffer pointer
    }
  } else { // rxd buffer overrun
    ptr_rxd_buffer = 0; // reset rxd buffer
    rxd_buffer_locked = FALSE; // unlock rxd buffer
  }
}

// --------------------------------------------------------------------------
void AddCRC(uint16_t datalen) {
  uint16_t tmpCRC = 0, i;
  for(i = 0; i < datalen; i++) {
    tmpCRC += txd_buffer[i];
  }
  tmpCRC %= 4096;
  txd_buffer[i++] = '=' + tmpCRC / 64;
  txd_buffer[i++] = '=' + tmpCRC % 64;
  txd_buffer[i++] = '\r';
  txd_complete = FALSE;
  UDR0 = txd_buffer[0]; // initiates the transmittion (continued in the TXD ISR)
}

// --------------------------------------------------------------------------
// application example:
// SendOutData('A', FC_ADDRESS, 2, (uint8_t *)&request_DebugLabel, sizeof(request_DebugLabel), label, 16);
/*
void SendOutData(uint8_t cmd, uint8_t addr, uint8_t numofbuffers, ...) { // uint8_t *pdata, uint8_t len, ...
  va_list ap;
  uint16_t txd_bufferIndex = 0;
  uint8_t *currentBuffer;
  uint8_t currentBufferIndex;
  uint16_t lengthOfCurrentBuffer;
  uint8_t shift = 0;
 
  txd_buffer[txd_bufferIndex++] = '#';                  // Start character
  txd_buffer[txd_bufferIndex++] = 'a' + addr;           // Address (a=0; b=1,...)
  txd_buffer[txd_bufferIndex++] = cmd;                  // Command
 
  va_start(ap, numofbuffers);

  while(numofbuffers) {
    currentBuffer = va_arg(ap, uint8_t*);
    lengthOfCurrentBuffer = va_arg(ap, int);
    currentBufferIndex = 0;
    // Encode data: 3 bytes of data are encoded into 4 bytes,
    // where the 2 most significant bits are both 0.
    while(currentBufferIndex != lengthOfCurrentBuffer) {
      if (!shift) txd_buffer[txd_bufferIndex] = 0;
      txd_buffer[txd_bufferIndex]  |= currentBuffer[currentBufferIndex] >> (shift + 2);
      txd_buffer[++txd_bufferIndex] = (currentBuffer[currentBufferIndex] << (4 - shift)) & 0b00111111;
      shift += 2;
      if (shift == 6) { shift=0; txd_bufferIndex++; }
      currentBufferIndex++;
    }
  }
  // If the number of data bytes was not divisible by 3, stuff
  //  with 0 pseudodata  until length is again divisible by 3.
  if (shift == 2) {
    // We need to stuff with zero bytes at the end.
    txd_buffer[txd_bufferIndex]  &= 0b00110000;
    txd_buffer[++txd_bufferIndex] = 0;
    shift = 4;
  }
  if (shift == 4) {
    // We need to stuff with zero bytes at the end.
    txd_buffer[txd_bufferIndex++] &= 0b00111100;
    txd_buffer[txd_bufferIndex]    = 0;
  }
  va_end(ap);
  AddCRC(pt); // add checksum after data block and initates the transmission
}
*/

void SendOutData(uint8_t cmd, uint8_t addr, uint8_t numofbuffers, ...) { // uint8_t *pdata, uint8_t len, ...
  va_list ap;
  uint16_t pt = 0;
  uint8_t a,b,c;
  uint8_t ptr = 0;
 
  uint8_t *pdata = 0;
  int len = 0;
 
  txd_buffer[pt++] = '#';                       // Start character
  txd_buffer[pt++] = 'a' + addr;        // Address (a=0; b=1,...)
  txd_buffer[pt++] = cmd;                       // Command
 
  va_start(ap, numofbuffers);

  if(numofbuffers) {
    pdata = va_arg(ap, uint8_t*);
    len = va_arg(ap, int);
    ptr = 0;
    numofbuffers--;
  }

  while(len){
    if(len) {
      a = pdata[ptr++];
      len--;
      if((!len) && numofbuffers) {
        pdata = va_arg(ap, uint8_t*);
        len = va_arg(ap, int);
        ptr = 0;
        numofbuffers--;
      }
    }
    else a = 0;
    if(len) {
      b = pdata[ptr++];
      len--;
      if((!len) && numofbuffers) {
        pdata = va_arg(ap, uint8_t*);
        len = va_arg(ap, int);
        ptr = 0;
        numofbuffers--;
      }
    } else b = 0;
    if(len) {
      c = pdata[ptr++];
      len--;
      if((!len) && numofbuffers) {
        pdata = va_arg(ap, uint8_t*);
        len = va_arg(ap, int);
        ptr = 0;
        numofbuffers--;
      }
    }
    else c = 0;
    txd_buffer[pt++] = '=' + (a >> 2);
    txd_buffer[pt++] = '=' + (((a & 0x03) << 4) | ((b & 0xf0) >> 4));
    txd_buffer[pt++] = '=' + (((b & 0x0f) << 2) | ((c & 0xc0) >> 6));
    txd_buffer[pt++] = '=' + ( c & 0x3f);
  }
  va_end(ap);
  AddCRC(pt); // add checksum after data block and initates the transmission
}

// --------------------------------------------------------------------------
void Decode64(void) {
  uint8_t a,b,c,d;
  uint8_t x,y,z;
  uint8_t ptrIn = 3;
  uint8_t ptrOut = 3;
  uint8_t len = ReceivedBytes - 6;
 
  while(len) {
    a = rxd_buffer[ptrIn++] - '=';
    b = rxd_buffer[ptrIn++] - '=';
    c = rxd_buffer[ptrIn++] - '=';
    d = rxd_buffer[ptrIn++] - '=';
    //if(ptrIn > ReceivedBytes - 3) break;
   
    x = (a << 2) | (b >> 4);
    y = ((b & 0x0f) << 4) | (c >> 2);
    z = ((c & 0x03) << 6) | d;
   
    if(len--) rxd_buffer[ptrOut++] = x; else break;
    if(len--) rxd_buffer[ptrOut++] = y; else break;
    if(len--) rxd_buffer[ptrOut++] = z; else break;
  }
  pRxData = &rxd_buffer[3];
  RxDataLen = ptrOut - 3;
}

// --------------------------------------------------------------------------
void usart0_ProcessRxData(void) {
  // We control the motorTestActive var from here: Count it down.
  if (motorTestActive) motorTestActive--;
  // if data in the rxd buffer are not locked immediately return
  if(!rxd_buffer_locked) return;
  uint8_t tempchar1, tempchar2;
  Decode64(); // decode data block in rxd_buffer

  switch(rxd_buffer[1] - 'a') {

  case FC_ADDRESS:
    switch(rxd_buffer[2]) {
#ifdef USE_MK3MAG
    case 'K':// compass value
      compassHeading = ((Heading_t *)pRxData)->Heading;
      compassOffCourse = ((540 + compassHeading - compassCourse) % 360) - 180;
      break;
#endif
    case 't': // motor test
      if(RxDataLen > 20) {
        memcpy(&motorTest[0], (uint8_t*)pRxData, sizeof(motorTest));
      } else {
        memcpy(&motorTest[0], (uint8_t*)pRxData, 4);
      }
      motorTestActive = 255;
      externalControlActive = 255;
      break;
     
    case 'n':// "Get Mixer Table
      while(!txd_complete); // wait for previous frame to be sent
      SendOutData('N', FC_ADDRESS, 1, (uint8_t *) &Mixer, sizeof(Mixer));
      break;

    case 'm':// "Set Mixer Table
      if(pRxData[0] == EEMIXER_REVISION) {
        memcpy(&Mixer, (uint8_t*)pRxData, sizeof(Mixer));
        MixerTable_WriteToEEProm();
        while(!txd_complete); // wait for previous frame to be sent
        tempchar1 = 1;
      } else {
        tempchar1 = 0;
      }
      SendOutData('M', FC_ADDRESS,  1, &tempchar1, 1);
      break;

    case 'p': // get PPM channels
      request_PPMChannels = TRUE;
      break;

    case 'q':// request settings
      if(pRxData[0] == 0xFF) {
        pRxData[0] = GetParamByte(PID_ACTIVE_SET);
      }
      // limit settings range
      if(pRxData[0] < 1) pRxData[0] = 1; // limit to 1
      else if(pRxData[0] > 5) pRxData[0] = 5; // limit to 5
      // load requested parameter set
      ParamSet_ReadFromEEProm(pRxData[0]);
      tempchar1 = pRxData[0];
      tempchar2 = EEPARAM_REVISION;
      while(!txd_complete); // wait for previous frame to be sent
      SendOutData('Q', FC_ADDRESS,3, &tempchar1, sizeof(tempchar1), &tempchar2, sizeof(tempchar2), (uint8_t *) &staticParams, sizeof(staticParams));
      break;

    case 's': // save settings
      if(!(MKFlags & MKFLAG_MOTOR_RUN)) // save settings only if motors ar off
        {
          if((1 <= pRxData[0]) && (pRxData[0] <= 5) && (pRxData[1] == EEPARAM_REVISION)) // check for setting to be in range and version of settings
            {
              memcpy(&staticParams, (uint8_t*)&pRxData[2], sizeof(staticParams));
              ParamSet_WriteToEEProm(pRxData[0]);
              /*
                TODO: Remove this encapsulation breach
                turnOver180Pitch = (int32_t) staticParams.AngleTurnOverPitch * 2500L;
                turnOver180Roll = (int32_t) staticParams.AngleTurnOverRoll * 2500L;
              */
              tempchar1 = getActiveParamSet();
              beepNumber(tempchar1);
            }
          else
            {
              tempchar1 = 0;    //indicate bad data
            }
          while(!txd_complete); // wait for previous frame to be sent
          SendOutData('S', FC_ADDRESS,1, &tempchar1, sizeof(tempchar1));
        }
      break;

    default:
      //unsupported command received
      break;
    } // case FC_ADDRESS:

  default: // any Slave Address
    switch(rxd_buffer[2]) {
      case 'a':// request for labels of the analog debug outputs
        request_DebugLabel = pRxData[0];
        if(request_DebugLabel > 31) request_DebugLabel = 31;
        externalControlActive = 255;
        break;

      case 'b': // submit extern control
        memcpy(&externalControl, (uint8_t*)pRxData, sizeof(externalControl));
        ConfirmFrame = externalControl.frame;
        externalControlActive = 255;
        break;

      case 'h':// request for display columns
        externalControlActive = 255;
        RemoteKeys |= pRxData[0];
        if(RemoteKeys) DisplayLine = 0;
        request_Display = TRUE;
        break;

      case 'l':// request for display columns
        externalControlActive = 255;
        MenuItem = pRxData[0];
        request_Display1 = TRUE;
        break;

      case 'v': // request for version and board release
        request_VerInfo = TRUE;
        break;

    case 'x':
      request_variables = TRUE;
      break;

      case 'g':// get external control data
        request_ExternalControl = TRUE;
        break;

      case 'd': // request for the debug data
        DebugData_Interval = (uint16_t) pRxData[0] * 10;
        if(DebugData_Interval > 0) request_DebugData = TRUE;
        break;

      case 'c': // request for the 3D data
        Data3D_Interval = (uint16_t) pRxData[0] * 10;
        if(Data3D_Interval > 0) request_Data3D = TRUE;
        break;

      default:
        //unsupported command received
        break;
      }
    break; // default:
  }
  // unlock the rxd buffer after processing
  pRxData = 0;
  RxDataLen = 0;
  rxd_buffer_locked = FALSE;
}

/************************************************************************/
/* Routine für die Serielle Ausgabe                                     */
/************************************************************************/
int16_t uart_putchar (int8_t c) {
  if (c == '\n')
    uart_putchar('\r');
  // wait until previous character was send
  loop_until_bit_is_set(UCSR0A, UDRE0);
  // send character
  UDR0 = c;
  return (0);
}

//---------------------------------------------------------------------------------------------
void usart0_TransmitTxData(void) {
  if(!txd_complete) return;

  if(request_VerInfo && txd_complete) {
    SendOutData('V', FC_ADDRESS, 1, (uint8_t *) &UART_VersionInfo, sizeof(UART_VersionInfo));
    request_VerInfo = FALSE;
  }
 
  if(request_Display && txd_complete) {
    LCD_PrintMenu();
    SendOutData('H', FC_ADDRESS, 2, &DisplayLine, sizeof(DisplayLine), &DisplayBuff[DisplayLine * 20], 20);
    DisplayLine++;
    if(DisplayLine >= 4) DisplayLine = 0;
    request_Display = FALSE;
  }
 
  if(request_Display1 && txd_complete) {
    LCD_PrintMenu();
    SendOutData('L', FC_ADDRESS, 3, &MenuItem, sizeof(MenuItem), &MaxMenuItem, sizeof(MaxMenuItem), DisplayBuff, sizeof(DisplayBuff));
    request_Display1 = FALSE;
  }
 
  if(request_DebugLabel != 0xFF) { // Texte für die Analogdaten
    uint8_t label[16]; // local sram buffer
    memcpy_P(label, ANALOG_LABEL[request_DebugLabel], 16); // read lable from flash to sram buffer
    SendOutData('A', FC_ADDRESS, 2, (uint8_t *) &request_DebugLabel, sizeof(request_DebugLabel), label, 16);
    request_DebugLabel = 0xFF;
  }
 
  if(ConfirmFrame && txd_complete) {   // Datensatz ohne CRC bestätigen
    SendOutData('B', FC_ADDRESS, 1, (uint8_t*)&ConfirmFrame, sizeof(ConfirmFrame));
    ConfirmFrame = 0;
  }
 
  if(((DebugData_Interval && CheckDelay(DebugData_Timer)) || request_DebugData) && txd_complete) {
    SendOutData('D', FC_ADDRESS, 1,(uint8_t *) &DebugOut, sizeof(DebugOut));
    DebugData_Timer = SetDelay(DebugData_Interval);
    request_DebugData = FALSE;
  }
 
  if( ((Data3D_Interval && CheckDelay(Data3D_Timer)) || request_Data3D) && txd_complete) {
    SendOutData('C', FC_ADDRESS, 1,(uint8_t *) &Data3D, sizeof(Data3D));
    Data3D.AngleNick = (int16_t)((10 * angle[PITCH]) / GYRO_DEG_FACTOR_PITCHROLL); // convert to multiple of 0.1°
    Data3D.AngleRoll = (int16_t)((10 * angle[ROLL]) / GYRO_DEG_FACTOR_PITCHROLL); // convert to multiple of 0.1°
    Data3D.Heading   = (int16_t)((10 * yawGyroHeading)   / GYRO_DEG_FACTOR_YAW); // convert to multiple of 0.1°
    Data3D_Timer = SetDelay(Data3D_Interval);
    request_Data3D = FALSE;
  }

  if(request_ExternalControl && txd_complete) {
    SendOutData('G', FC_ADDRESS, 1,(uint8_t *) &externalControl, sizeof(externalControl));
    request_ExternalControl = FALSE;
  }

#ifdef USE_MK3MAG
  if((CheckDelay(Compass_Timer)) && txd_complete) {
    ToMk3Mag.Attitude[0] = (int16_t)((10 * angle[PITCH]) / GYRO_DEG_FACTOR_PITCHROLL);  // approx. 0.1 deg
    ToMk3Mag.Attitude[1] = (int16_t)((10 * angle[ROLL]) / GYRO_DEG_FACTOR_PITCHROLL);  // approx. 0.1 deg
    ToMk3Mag.UserParam[0] = dynamicParams.UserParams[0];
    ToMk3Mag.UserParam[1] = dynamicParams.UserParams[1];
    ToMk3Mag.CalState = compassCalState;
    SendOutData('w', MK3MAG_ADDRESS, 1,(uint8_t *) &ToMk3Mag,sizeof(ToMk3Mag));
    // the last state is 5 and should be send only once to avoid multiple flash writing
    if(compassCalState > 4)  compassCalState = 0;
    Compass_Timer = SetDelay(99);
  }
#endif
 
  if(request_MotorTest && txd_complete) {
    SendOutData('T', FC_ADDRESS, 0);
    request_MotorTest = FALSE;
  }

  if(request_PPMChannels && txd_complete) {
    SendOutData('P', FC_ADDRESS, 1, (uint8_t *)&PPM_in, sizeof(PPM_in));
    request_PPMChannels = FALSE;
  }

  if (request_variables && txd_complete) {
    SendOutData('X', FC_ADDRESS, 1, (uint8_t *)&variables, sizeof(variables));
    request_variables = FALSE;
  }
}