protocol2_packet_handler.cpp

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/*******************************************************************************
* Copyright (C) 2021 <Robot Articulation/code@robotarticulation.com> 
*
* Source files modified to support the Mercury range of digital servo motors from Robot Articulation
*******************************************************************************/
 
/*******************************************************************************
* Copyright 2017 ROBOTIS CO., LTD.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
 
/* Original author: Zerom, Leon (RyuWoon Jung) */
 
#if defined(__linux__)
#include <unistd.h>
#include "protocol2_packet_handler.h"
#elif defined(__APPLE__)
#include <unistd.h>
#include "protocol2_packet_handler.h"
#elif defined(_WIN32) || defined(_WIN64)
#define WINDLLEXPORT
#include <Windows.h>
#include "protocol2_packet_handler.h"
#elif defined(ARDUINO) || defined(__OPENCR__) || defined(__OPENCM904__)
#include "../../include/mercury_sdk/protocol2_packet_handler.h"
#endif
 
#include <stdio.h>
#include <stdlib.h>
 
#define TXPACKET_MAX_LEN    (1*1024)
#define RXPACKET_MAX_LEN    (1*1024)
 
#define PKT_HEADER0             0
#define PKT_HEADER1             1
#define PKT_HEADER2             2
#define PKT_RESERVED            3
#define PKT_ID                  4
#define PKT_LENGTH_L            5
#define PKT_LENGTH_H            6
#define PKT_INSTRUCTION         7
#define PKT_ERROR               8
#define PKT_PARAMETER0          8
 
#define ERRNUM_RESULT_FAIL      1       // Failed to process the instruction packet.
#define ERRNUM_INSTRUCTION      2       // Instruction error
#define ERRNUM_CRC              3       // CRC check error
#define ERRNUM_DATA_RANGE       4       // Data range error
#define ERRNUM_DATA_LENGTH      5       // Data length error
#define ERRNUM_DATA_LIMIT       6       // Data limit error
#define ERRNUM_ACCESS           7       // Access error
 
#define ERRBIT_ALERT            128     //When the device has a problem, this bit is set to 1. Check "Device Status Check" value.
 
using namespace mercury;
 
Protocol2PacketHandler *Protocol2PacketHandler::unique_instance_ = new Protocol2PacketHandler();
 
Protocol2PacketHandler::Protocol2PacketHandler() { }
 
const char *Protocol2PacketHandler::getTxRxResult(int result)
{
  switch(result)
  {
    case COMM_SUCCESS:
      return "[TxRxResult] Communication success.";
 
    case COMM_PORT_BUSY:
      return "[TxRxResult] Port is in use!";
 
    case COMM_TX_FAIL:
      return "[TxRxResult] Failed transmit instruction packet!";
 
    case COMM_RX_FAIL:
      return "[TxRxResult] Failed get status packet from device!";
 
    case COMM_TX_ERROR:
      return "[TxRxResult] Incorrect instruction packet!";
 
    case COMM_RX_WAITING:
      return "[TxRxResult] Now recieving status packet!";
 
    case COMM_RX_TIMEOUT:
      return "[TxRxResult] There is no status packet!";
 
    case COMM_RX_CORRUPT:
      return "[TxRxResult] Incorrect status packet!";
 
    case COMM_NOT_AVAILABLE:
      return "[TxRxResult] Protocol does not support This function!";
 
    default:
      return "";
  }
}
 
const char *Protocol2PacketHandler::getRxPacketError(uint8_t error)
{
  if (error & ERRBIT_ALERT)
    return "[RxPacketError] Hardware error occurred. Check the error at Control Table (Hardware Error Status)!";
 
  int not_alert_error = error & ~ERRBIT_ALERT;
 
  switch(not_alert_error)
  {
    case 0:
      return "";
 
    case ERRNUM_RESULT_FAIL:
      return "[RxPacketError] Failed to process the instruction packet!";
 
    case ERRNUM_INSTRUCTION:
      return "[RxPacketError] Undefined instruction or incorrect instruction!";
 
    case ERRNUM_CRC:
      return "[RxPacketError] CRC doesn't match!";
 
    case ERRNUM_DATA_RANGE:
      return "[RxPacketError] The data value is out of range!";
 
    case ERRNUM_DATA_LENGTH:
      return "[RxPacketError] The data length does not match as expected!";
 
    case ERRNUM_DATA_LIMIT:
      return "[RxPacketError] The data value exceeds the limit value!";
 
    case ERRNUM_ACCESS:
      return "[RxPacketError] Writing or Reading is not available to target address!";
 
    default:
      return "[RxPacketError] Unknown error code!";
  }
}
 
unsigned short Protocol2PacketHandler::updateCRC(uint16_t crc_accum, uint8_t *data_blk_ptr, uint16_t data_blk_size)
{
  uint16_t i;
  static const uint16_t crc_table[256] = {0x0000,
  0x8005, 0x800F, 0x000A, 0x801B, 0x001E, 0x0014, 0x8011,
  0x8033, 0x0036, 0x003C, 0x8039, 0x0028, 0x802D, 0x8027,
  0x0022, 0x8063, 0x0066, 0x006C, 0x8069, 0x0078, 0x807D,
  0x8077, 0x0072, 0x0050, 0x8055, 0x805F, 0x005A, 0x804B,
  0x004E, 0x0044, 0x8041, 0x80C3, 0x00C6, 0x00CC, 0x80C9,
  0x00D8, 0x80DD, 0x80D7, 0x00D2, 0x00F0, 0x80F5, 0x80FF,
  0x00FA, 0x80EB, 0x00EE, 0x00E4, 0x80E1, 0x00A0, 0x80A5,
  0x80AF, 0x00AA, 0x80BB, 0x00BE, 0x00B4, 0x80B1, 0x8093,
  0x0096, 0x009C, 0x8099, 0x0088, 0x808D, 0x8087, 0x0082,
  0x8183, 0x0186, 0x018C, 0x8189, 0x0198, 0x819D, 0x8197,
  0x0192, 0x01B0, 0x81B5, 0x81BF, 0x01BA, 0x81AB, 0x01AE,
  0x01A4, 0x81A1, 0x01E0, 0x81E5, 0x81EF, 0x01EA, 0x81FB,
  0x01FE, 0x01F4, 0x81F1, 0x81D3, 0x01D6, 0x01DC, 0x81D9,
  0x01C8, 0x81CD, 0x81C7, 0x01C2, 0x0140, 0x8145, 0x814F,
  0x014A, 0x815B, 0x015E, 0x0154, 0x8151, 0x8173, 0x0176,
  0x017C, 0x8179, 0x0168, 0x816D, 0x8167, 0x0162, 0x8123,
  0x0126, 0x012C, 0x8129, 0x0138, 0x813D, 0x8137, 0x0132,
  0x0110, 0x8115, 0x811F, 0x011A, 0x810B, 0x010E, 0x0104,
  0x8101, 0x8303, 0x0306, 0x030C, 0x8309, 0x0318, 0x831D,
  0x8317, 0x0312, 0x0330, 0x8335, 0x833F, 0x033A, 0x832B,
  0x032E, 0x0324, 0x8321, 0x0360, 0x8365, 0x836F, 0x036A,
  0x837B, 0x037E, 0x0374, 0x8371, 0x8353, 0x0356, 0x035C,
  0x8359, 0x0348, 0x834D, 0x8347, 0x0342, 0x03C0, 0x83C5,
  0x83CF, 0x03CA, 0x83DB, 0x03DE, 0x03D4, 0x83D1, 0x83F3,
  0x03F6, 0x03FC, 0x83F9, 0x03E8, 0x83ED, 0x83E7, 0x03E2,
  0x83A3, 0x03A6, 0x03AC, 0x83A9, 0x03B8, 0x83BD, 0x83B7,
  0x03B2, 0x0390, 0x8395, 0x839F, 0x039A, 0x838B, 0x038E,
  0x0384, 0x8381, 0x0280, 0x8285, 0x828F, 0x028A, 0x829B,
  0x029E, 0x0294, 0x8291, 0x82B3, 0x02B6, 0x02BC, 0x82B9,
  0x02A8, 0x82AD, 0x82A7, 0x02A2, 0x82E3, 0x02E6, 0x02EC,
  0x82E9, 0x02F8, 0x82FD, 0x82F7, 0x02F2, 0x02D0, 0x82D5,
  0x82DF, 0x02DA, 0x82CB, 0x02CE, 0x02C4, 0x82C1, 0x8243,
  0x0246, 0x024C, 0x8249, 0x0258, 0x825D, 0x8257, 0x0252,
  0x0270, 0x8275, 0x827F, 0x027A, 0x826B, 0x026E, 0x0264,
  0x8261, 0x0220, 0x8225, 0x822F, 0x022A, 0x823B, 0x023E,
  0x0234, 0x8231, 0x8213, 0x0216, 0x021C, 0x8219, 0x0208,
  0x820D, 0x8207, 0x0202 };
 
  for (uint16_t j = 0; j < data_blk_size; j++)
  {
    i = ((uint16_t)(crc_accum >> 8) ^ *data_blk_ptr++) & 0xFF;
    crc_accum = (crc_accum << 8) ^ crc_table[i];
  }
 
  return crc_accum;
}
 
void Protocol2PacketHandler::addStuffing(uint8_t *packet)
{
  int packet_length_in = MCY_MAKEWORD(packet[PKT_LENGTH_L], packet[PKT_LENGTH_H]);
  int packet_length_out = packet_length_in;
  
  if (packet_length_in < 8) // INSTRUCTION, ADDR_L, ADDR_H, CRC16_L, CRC16_H + FF FF FD
    return;
 
  uint8_t *packet_ptr;
  uint16_t packet_length_before_crc = packet_length_in - 2;
  for (uint16_t i = 3; i < packet_length_before_crc; i++)
  {
    packet_ptr = &packet[i+PKT_INSTRUCTION-2];
    if (packet_ptr[0] == 0xFF && packet_ptr[1] == 0xFF && packet_ptr[2] == 0xFD)
      packet_length_out++;
  }
  
  if (packet_length_in == packet_length_out)  // no stuffing required
    return;
  
  uint16_t out_index  = packet_length_out + 6 - 2;  // last index before crc
  uint16_t in_index   = packet_length_in + 6 - 2;   // last index before crc
  while (out_index != in_index)
  {
    if (packet[in_index] == 0xFD && packet[in_index-1] == 0xFF && packet[in_index-2] == 0xFF)
    {
      packet[out_index--] = 0xFD; // byte stuffing
      if (out_index != in_index)
      {
        packet[out_index--] = packet[in_index--]; // FD
        packet[out_index--] = packet[in_index--]; // FF
        packet[out_index--] = packet[in_index--]; // FF
      }
    }
    else
    {
      packet[out_index--] = packet[in_index--];
    }
  }
 
  packet[PKT_LENGTH_L] = MCY_LOBYTE(packet_length_out);
  packet[PKT_LENGTH_H] = MCY_HIBYTE(packet_length_out);
 
  return;
}
 
void Protocol2PacketHandler::removeStuffing(uint8_t *packet)
{
  int i = 0, index = 0;
  int packet_length_in = MCY_MAKEWORD(packet[PKT_LENGTH_L], packet[PKT_LENGTH_H]);
  int packet_length_out = packet_length_in;
 
  index = PKT_INSTRUCTION;
  for (i = 0; i < packet_length_in - 2; i++)  // except CRC
  {
    if (packet[i+PKT_INSTRUCTION] == 0xFD && packet[i+PKT_INSTRUCTION+1] == 0xFD && packet[i+PKT_INSTRUCTION-1] == 0xFF && packet[i+PKT_INSTRUCTION-2] == 0xFF)
    {   
      packet_length_out--;
      i++;
    }
    packet[index++] = packet[i+PKT_INSTRUCTION];
  }
  packet[index++] = packet[PKT_INSTRUCTION+packet_length_in-2];
  packet[index++] = packet[PKT_INSTRUCTION+packet_length_in-1];
 
  packet[PKT_LENGTH_L] = MCY_LOBYTE(packet_length_out);
  packet[PKT_LENGTH_H] = MCY_HIBYTE(packet_length_out);
}
 
int Protocol2PacketHandler::txPacket(PortHandler *port, uint8_t *txpacket)
{
  uint16_t total_packet_length   = 0;
  uint16_t written_packet_length = 0;
 
  if (port->is_using_)
    return COMM_PORT_BUSY;
  port->is_using_ = true;
 
  // byte stuffing for header
  addStuffing(txpacket);
 
  // check max packet length
  total_packet_length = MCY_MAKEWORD(txpacket[PKT_LENGTH_L], txpacket[PKT_LENGTH_H]) + 7;
  // 7: HEADER0 HEADER1 HEADER2 RESERVED ID LENGTH_L LENGTH_H
  if (total_packet_length > TXPACKET_MAX_LEN)
  {
    port->is_using_ = false;
    return COMM_TX_ERROR;
  }
 
  // make packet header
  txpacket[PKT_HEADER0]   = 0xFF;
  txpacket[PKT_HEADER1]   = 0xFF;
  txpacket[PKT_HEADER2]   = 0xFD;
  txpacket[PKT_RESERVED]  = 0x00;
 
  // add CRC16
  uint16_t crc = updateCRC(0, txpacket, total_packet_length - 2);    // 2: CRC16
  txpacket[total_packet_length - 2] = MCY_LOBYTE(crc);
  txpacket[total_packet_length - 1] = MCY_HIBYTE(crc);
 
  // tx packet
  port->clearPort();
  written_packet_length = port->writePort(txpacket, total_packet_length);
  if (total_packet_length != written_packet_length)
  {
    port->is_using_ = false;
    return COMM_TX_FAIL;
  }
 
  return COMM_SUCCESS;
}
 
int Protocol2PacketHandler::rxPacket(PortHandler *port, uint8_t *rxpacket)
{
  int     result         = COMM_TX_FAIL;
 
  uint16_t rx_length     = 0;
  uint16_t wait_length   = 11; // minimum length (HEADER0 HEADER1 HEADER2 RESERVED ID LENGTH_L LENGTH_H INST ERROR CRC16_L CRC16_H)
 
  while(true)
  {
    rx_length += port->readPort(&rxpacket[rx_length], wait_length - rx_length);
    if (rx_length >= wait_length)
    {
      uint16_t idx = 0;
 
      // find packet header
      for (idx = 0; idx < (rx_length - 3); idx++)
      {
        if ((rxpacket[idx] == 0xFF) && (rxpacket[idx+1] == 0xFF) && (rxpacket[idx+2] == 0xFD) && (rxpacket[idx+3] != 0xFD))
          break;
      }
 
      if (idx == 0)   // found at the beginning of the packet
      {
        if (rxpacket[PKT_RESERVED] != 0x00 ||
           rxpacket[PKT_ID] > 0xFC ||
           MCY_MAKEWORD(rxpacket[PKT_LENGTH_L], rxpacket[PKT_LENGTH_H]) > RXPACKET_MAX_LEN ||
           rxpacket[PKT_INSTRUCTION] != 0x55)
        {
          // remove the first byte in the packet
          for (uint16_t s = 0; s < rx_length - 1; s++)
            rxpacket[s] = rxpacket[1 + s];
 
          rx_length -= 1;
          continue;
        }
 
        // re-calculate the exact length of the rx packet
        if (wait_length != MCY_MAKEWORD(rxpacket[PKT_LENGTH_L], rxpacket[PKT_LENGTH_H]) + PKT_LENGTH_H + 1)
        {
          wait_length = MCY_MAKEWORD(rxpacket[PKT_LENGTH_L], rxpacket[PKT_LENGTH_H]) + PKT_LENGTH_H + 1;
          continue;
        }
 
        if (rx_length < wait_length)
        {
          // check timeout
          if (port->isPacketTimeout() == true)
          {
            if (rx_length == 0)
            {
              result = COMM_RX_TIMEOUT;
            }
            else
            {
              result = COMM_RX_CORRUPT;
            }
            break;
          }
          else
          {
            continue;
          }
        }
 
        // verify CRC16
        uint16_t crc = MCY_MAKEWORD(rxpacket[wait_length-2], rxpacket[wait_length-1]);
        if (updateCRC(0, rxpacket, wait_length - 2) == crc)
        {
          result = COMM_SUCCESS;
        }
        else
        {
          result = COMM_RX_CORRUPT;
        }
        break;
      }
      else
      {
        // remove unnecessary packets
        for (uint16_t s = 0; s < rx_length - idx; s++)
          rxpacket[s] = rxpacket[idx + s];
 
        rx_length -= idx;
      }
    }
    else
    {
      // check timeout
      if (port->isPacketTimeout() == true)
      {
        if (rx_length == 0)
        {
          result = COMM_RX_TIMEOUT;
        }
        else
        {
          result = COMM_RX_CORRUPT;
        }
        break;
      }
    }
#if defined(__linux__) || defined(__APPLE__)
    usleep(0);
#elif defined(_WIN32) || defined(_WIN64)
    Sleep(0);
#endif
  }
  port->is_using_ = false;
 
  if (result == COMM_SUCCESS)
    removeStuffing(rxpacket);
 
  return result;
}
 
// NOT for BulkRead / SyncRead instruction
int Protocol2PacketHandler::txRxPacket(PortHandler *port, uint8_t *txpacket, uint8_t *rxpacket, uint8_t *error)
{
  int result = COMM_TX_FAIL;
 
  // tx packet
  result = txPacket(port, txpacket);
  if (result != COMM_SUCCESS)
    return result;
 
  if (txpacket[PKT_ID] == BROADCAST_ID || txpacket[PKT_INSTRUCTION] == INST_ACTION)
  {
    port->is_using_ = false;
    return result;
  }
 
  // set packet timeout
  if (txpacket[PKT_INSTRUCTION] == INST_READ)
  {
    port->setPacketTimeout((uint16_t)(MCY_MAKEWORD(txpacket[PKT_PARAMETER0+2], txpacket[PKT_PARAMETER0+3]) + 11));
  }
  else
  {
    port->setPacketTimeout((uint16_t)11);
    // HEADER0 HEADER1 HEADER2 RESERVED ID LENGTH_L LENGTH_H INST ERROR CRC16_L CRC16_H
  }
 
  // rx packet
  do {
    result = rxPacket(port, rxpacket);
  } while (result == COMM_SUCCESS && txpacket[PKT_ID] != rxpacket[PKT_ID]);
 
  if (result == COMM_SUCCESS && txpacket[PKT_ID] == rxpacket[PKT_ID])
  {
    if (error != 0)
      *error = (uint8_t)rxpacket[PKT_ERROR];
  }
 
  return result;
}
 
int Protocol2PacketHandler::ping(PortHandler *port, uint8_t id, uint8_t *error)
{
  return ping(port, id, 0, error);
}
 
int Protocol2PacketHandler::ping(PortHandler *port, uint8_t id, uint16_t *model_number, uint8_t *error)
{
  int result                 = COMM_TX_FAIL;
 
  uint8_t txpacket[10]        = {0};
  uint8_t rxpacket[14]        = {0};
 
  if (id >= BROADCAST_ID)
    return COMM_NOT_AVAILABLE;
 
  txpacket[PKT_ID]            = id;
  txpacket[PKT_LENGTH_L]      = 3;
  txpacket[PKT_LENGTH_H]      = 0;
  txpacket[PKT_INSTRUCTION]   = INST_PING;
 
  result = txRxPacket(port, txpacket, rxpacket, error);
  if (result == COMM_SUCCESS && model_number != 0)
    *model_number = MCY_MAKEWORD(rxpacket[PKT_PARAMETER0+1], rxpacket[PKT_PARAMETER0+2]);
 
  return result;
}
 
int Protocol2PacketHandler::broadcastPing(PortHandler *port, std::vector<uint8_t> &id_list)
{
  const int STATUS_LENGTH     = 14;
  int result                  = COMM_TX_FAIL;
 
  id_list.clear();
 
  uint16_t rx_length          = 0;
  uint16_t wait_length        = STATUS_LENGTH * MAX_ID;
 
  uint8_t txpacket[10]        = {0};
  uint8_t rxpacket[STATUS_LENGTH * MAX_ID] = {0};
 
  double tx_time_per_byte = (1000.0 / (double)port->getBaudRate()) * 10.0;
 
  txpacket[PKT_ID]            = BROADCAST_ID;
  txpacket[PKT_LENGTH_L]      = 3;
  txpacket[PKT_LENGTH_H]      = 0;
  txpacket[PKT_INSTRUCTION]   = INST_PING;
 
  result = txPacket(port, txpacket);
  if (result != COMM_SUCCESS)
  {
    port->is_using_ = false;
    return result;
  }
 
  // set rx timeout
  port->setPacketTimeout(((double)wait_length * tx_time_per_byte) + (3.0 * (double)MAX_ID) + 16.0);
 
  while(1)
  {
    rx_length += port->readPort(&rxpacket[rx_length], wait_length - rx_length);
    if (port->isPacketTimeout() == true)
      break;
  }
 
  port->is_using_ = false;
 
  if (rx_length == 0)
    return COMM_RX_TIMEOUT;
 
  while(1)
  {
    if (rx_length < STATUS_LENGTH)
      return COMM_RX_CORRUPT;
 
    uint16_t idx = 0;
 
    // find packet header
    for (idx = 0; idx < (rx_length - 2); idx++)
    {
      if (rxpacket[idx] == 0xFF && rxpacket[idx+1] == 0xFF && rxpacket[idx+2] == 0xFD)
        break;
    }
 
    if (idx == 0)   // found at the beginning of the packet
    {
      // verify CRC16
      uint16_t crc = MCY_MAKEWORD(rxpacket[STATUS_LENGTH-2], rxpacket[STATUS_LENGTH-1]);
 
      if (updateCRC(0, rxpacket, STATUS_LENGTH - 2) == crc)
      {
        result = COMM_SUCCESS;
 
        id_list.push_back(rxpacket[PKT_ID]);
 
        for (uint16_t s = 0; s < rx_length - STATUS_LENGTH; s++)
          rxpacket[s] = rxpacket[STATUS_LENGTH + s];
        rx_length -= STATUS_LENGTH;
 
        if (rx_length == 0)
          return result;
      }
      else
      {
        result = COMM_RX_CORRUPT;
 
        // remove header (0xFF 0xFF 0xFD)
        for (uint16_t s = 0; s < rx_length - 3; s++)
          rxpacket[s] = rxpacket[3 + s];
        rx_length -= 3;
      }
    }
    else
    {
      // remove unnecessary packets
      for (uint16_t s = 0; s < rx_length - idx; s++)
        rxpacket[s] = rxpacket[idx + s];
      rx_length -= idx;
    }
  }
 
  return result;
}
 
int Protocol2PacketHandler::action(PortHandler *port, uint8_t id)
{
  uint8_t txpacket[10]        = {0};
 
  txpacket[PKT_ID]            = id;
  txpacket[PKT_LENGTH_L]      = 3;
  txpacket[PKT_LENGTH_H]      = 0;
  txpacket[PKT_INSTRUCTION]   = INST_ACTION;
 
  return txRxPacket(port, txpacket, 0);
}
 
int Protocol2PacketHandler::reboot(PortHandler *port, uint8_t id, uint8_t *error)
{
  uint8_t txpacket[10]        = {0};
  uint8_t rxpacket[11]        = {0};
 
  txpacket[PKT_ID]            = id;
  txpacket[PKT_LENGTH_L]      = 3;
  txpacket[PKT_LENGTH_H]      = 0;
  txpacket[PKT_INSTRUCTION]   = INST_REBOOT;
 
  return txRxPacket(port, txpacket, rxpacket, error);
}
 
int Protocol2PacketHandler::clearMultiTurn(PortHandler *port, uint8_t id, uint8_t *error)
{
  uint8_t txpacket[15]        = {0};
  uint8_t rxpacket[11]        = {0};
 
  txpacket[PKT_ID]            = id;
  txpacket[PKT_LENGTH_L]      = 8;
  txpacket[PKT_LENGTH_H]      = 0;
  txpacket[PKT_INSTRUCTION]   = INST_CLEAR;
  txpacket[PKT_PARAMETER0]    = 0x01;
  txpacket[PKT_PARAMETER0+1]  = 0x44;
  txpacket[PKT_PARAMETER0+2]  = 0x58;
  txpacket[PKT_PARAMETER0+3]  = 0x4C;
  txpacket[PKT_PARAMETER0+4]  = 0x22;
 
  return txRxPacket(port, txpacket, rxpacket, error);
}
 
int Protocol2PacketHandler::factoryReset(PortHandler *port, uint8_t id, uint8_t option, uint8_t *error)
{
  uint8_t txpacket[11]        = {0};
  uint8_t rxpacket[11]        = {0};
 
  txpacket[PKT_ID]            = id;
  txpacket[PKT_LENGTH_L]      = 4;
  txpacket[PKT_LENGTH_H]      = 0;
  txpacket[PKT_INSTRUCTION]   = INST_FACTORY_RESET;
  txpacket[PKT_PARAMETER0]    = option;
 
  return txRxPacket(port, txpacket, rxpacket, error);
}
 
int Protocol2PacketHandler::readTx(PortHandler *port, uint8_t id, uint16_t address, uint16_t length)
{
  int result                 = COMM_TX_FAIL;
 
  uint8_t txpacket[14]        = {0};
 
  if (id >= BROADCAST_ID)
    return COMM_NOT_AVAILABLE;
 
  txpacket[PKT_ID]            = id;
  txpacket[PKT_LENGTH_L]      = 7;
  txpacket[PKT_LENGTH_H]      = 0;
  txpacket[PKT_INSTRUCTION]   = INST_READ;
  txpacket[PKT_PARAMETER0+0]  = (uint8_t)MCY_LOBYTE(address);
  txpacket[PKT_PARAMETER0+1]  = (uint8_t)MCY_HIBYTE(address);
  txpacket[PKT_PARAMETER0+2]  = (uint8_t)MCY_LOBYTE(length);
  txpacket[PKT_PARAMETER0+3]  = (uint8_t)MCY_HIBYTE(length);
 
  result = txPacket(port, txpacket);
 
  // set packet timeout
  if (result == COMM_SUCCESS)
    port->setPacketTimeout((uint16_t)(length + 11));
 
  return result;
}
 
int Protocol2PacketHandler::readRx(PortHandler *port, uint8_t id, uint16_t length, uint8_t *data, uint8_t *error)
{
  int result                  = COMM_TX_FAIL;
  uint8_t *rxpacket           = (uint8_t *)malloc(RXPACKET_MAX_LEN);
  
  if (rxpacket == NULL)
    return result;
  
  do {
    result = rxPacket(port, rxpacket);
  } while (result == COMM_SUCCESS && rxpacket[PKT_ID] != id);
 
  if (result == COMM_SUCCESS && rxpacket[PKT_ID] == id)
  {
    if (error != 0)
      *error = (uint8_t)rxpacket[PKT_ERROR];
 
    for (uint16_t s = 0; s < length; s++)
    {
      data[s] = rxpacket[PKT_PARAMETER0 + 1 + s];
    }
  }
 
  free(rxpacket);
  return result;
}
 
int Protocol2PacketHandler::readTxRx(PortHandler *port, uint8_t id, uint16_t address, uint16_t length, uint8_t *data, uint8_t *error)
{
  int result                  = COMM_TX_FAIL;
 
  uint8_t txpacket[14]        = {0};
  uint8_t *rxpacket           = (uint8_t *)malloc(RXPACKET_MAX_LEN);
 
  if (rxpacket == NULL)
    return result;
  
  if (id >= BROADCAST_ID)
  {
    free(rxpacket);
    return COMM_NOT_AVAILABLE;
  }
 
  txpacket[PKT_ID]            = id;
  txpacket[PKT_LENGTH_L]      = 7;
  txpacket[PKT_LENGTH_H]      = 0;
  txpacket[PKT_INSTRUCTION]   = INST_READ;
  txpacket[PKT_PARAMETER0+0]  = (uint8_t)MCY_LOBYTE(address);
  txpacket[PKT_PARAMETER0+1]  = (uint8_t)MCY_HIBYTE(address);
  txpacket[PKT_PARAMETER0+2]  = (uint8_t)MCY_LOBYTE(length);
  txpacket[PKT_PARAMETER0+3]  = (uint8_t)MCY_HIBYTE(length);
 
  result = txRxPacket(port, txpacket, rxpacket, error);
  if (result == COMM_SUCCESS)
  {
    if (error != 0)
      *error = (uint8_t)rxpacket[PKT_ERROR];
 
    for (uint16_t s = 0; s < length; s++)
    {
      data[s] = rxpacket[PKT_PARAMETER0 + 1 + s];
    }
  }
 
  free(rxpacket);
  return result;
}
 
int Protocol2PacketHandler::read1ByteTx(PortHandler *port, uint8_t id, uint16_t address)
{
  return readTx(port, id, address, 1);
}
int Protocol2PacketHandler::read1ByteRx(PortHandler *port, uint8_t id, uint8_t *data, uint8_t *error)
{
  uint8_t data_read[1] = {0};
  int result = readRx(port, id, 1, data_read, error);
  if (result == COMM_SUCCESS)
    *data = data_read[0];
  return result;
}
int Protocol2PacketHandler::read1ByteTxRx(PortHandler *port, uint8_t id, uint16_t address, uint8_t *data, uint8_t *error)
{
  uint8_t data_read[1] = {0};
  int result = readTxRx(port, id, address, 1, data_read, error);
  if (result == COMM_SUCCESS)
    *data = data_read[0];
  return result;
}
 
int Protocol2PacketHandler::read2ByteTx(PortHandler *port, uint8_t id, uint16_t address)
{
  return readTx(port, id, address, 2);
}
int Protocol2PacketHandler::read2ByteRx(PortHandler *port, uint8_t id, uint16_t *data, uint8_t *error)
{
  uint8_t data_read[2] = {0};
  int result = readRx(port, id, 2, data_read, error);
  if (result == COMM_SUCCESS)
    *data = MCY_MAKEWORD(data_read[0], data_read[1]);
  return result;
}
int Protocol2PacketHandler::read2ByteTxRx(PortHandler *port, uint8_t id, uint16_t address, uint16_t *data, uint8_t *error)
{
  uint8_t data_read[2] = {0};
  int result = readTxRx(port, id, address, 2, data_read, error);
  if (result == COMM_SUCCESS)
    *data = MCY_MAKEWORD(data_read[0], data_read[1]);
  return result;
}
 
int Protocol2PacketHandler::read4ByteTx(PortHandler *port, uint8_t id, uint16_t address)
{
  return readTx(port, id, address, 4);
}
int Protocol2PacketHandler::read4ByteRx(PortHandler *port, uint8_t id, uint32_t *data, uint8_t *error)
{
  uint8_t data_read[4] = {0};
  int result = readRx(port, id, 4, data_read, error);
  if (result == COMM_SUCCESS)
    *data = MCY_MAKEDWORD(MCY_MAKEWORD(data_read[0], data_read[1]), MCY_MAKEWORD(data_read[2], data_read[3]));
  return result;
}
int Protocol2PacketHandler::read4ByteTxRx(PortHandler *port, uint8_t id, uint16_t address, uint32_t *data, uint8_t *error)
{
  uint8_t data_read[4] = {0};
  int result = readTxRx(port, id, address, 4, data_read, error);
  if (result == COMM_SUCCESS)
    *data = MCY_MAKEDWORD(MCY_MAKEWORD(data_read[0], data_read[1]), MCY_MAKEWORD(data_read[2], data_read[3]));
  return result;
}
 
int Protocol2PacketHandler::writeTxOnly(PortHandler *port, uint8_t id, uint16_t address, uint16_t length, uint8_t *data)
{
  int result                  = COMM_TX_FAIL;
 
  uint8_t *txpacket           = (uint8_t *)malloc(length + 12 + (length / 3));
  
  if (txpacket == NULL)
    return result;
 
  txpacket[PKT_ID]            = id;
  txpacket[PKT_LENGTH_L]      = MCY_LOBYTE(length+5);
  txpacket[PKT_LENGTH_H]      = MCY_HIBYTE(length+5);
  txpacket[PKT_INSTRUCTION]   = INST_WRITE;
  txpacket[PKT_PARAMETER0+0]  = (uint8_t)MCY_LOBYTE(address);
  txpacket[PKT_PARAMETER0+1]  = (uint8_t)MCY_HIBYTE(address);
 
  for (uint16_t s = 0; s < length; s++)
    txpacket[PKT_PARAMETER0+2+s] = data[s];
 
  result = txPacket(port, txpacket);
  port->is_using_ = false;
 
  free(txpacket);
  return result;
}
 
int Protocol2PacketHandler::writeTxRx(PortHandler *port, uint8_t id, uint16_t address, uint16_t length, uint8_t *data, uint8_t *error)
{
  int result                  = COMM_TX_FAIL;
 
  uint8_t *txpacket           = (uint8_t *)malloc(length + 12 + (length / 3));
  uint8_t rxpacket[11]        = {0};
 
  if (txpacket == NULL)
    return result;
  
  txpacket[PKT_ID]            = id;
  txpacket[PKT_LENGTH_L]      = MCY_LOBYTE(length+5);
  txpacket[PKT_LENGTH_H]      = MCY_HIBYTE(length+5);
  txpacket[PKT_INSTRUCTION]   = INST_WRITE;
  txpacket[PKT_PARAMETER0+0]  = (uint8_t)MCY_LOBYTE(address);
  txpacket[PKT_PARAMETER0+1]  = (uint8_t)MCY_HIBYTE(address);
 
  for (uint16_t s = 0; s < length; s++)
    txpacket[PKT_PARAMETER0+2+s] = data[s];
 
  result = txRxPacket(port, txpacket, rxpacket, error);
 
  free(txpacket);
  return result;
}
 
int Protocol2PacketHandler::write1ByteTxOnly(PortHandler *port, uint8_t id, uint16_t address, uint8_t data)
{
  uint8_t data_write[1] = { data };
  return writeTxOnly(port, id, address, 1, data_write);
}
int Protocol2PacketHandler::write1ByteTxRx(PortHandler *port, uint8_t id, uint16_t address, uint8_t data, uint8_t *error)
{
  uint8_t data_write[1] = { data };
  return writeTxRx(port, id, address, 1, data_write, error);
}
 
int Protocol2PacketHandler::write2ByteTxOnly(PortHandler *port, uint8_t id, uint16_t address, uint16_t data)
{
  uint8_t data_write[2] = { MCY_LOBYTE(data), MCY_HIBYTE(data) };
  return writeTxOnly(port, id, address, 2, data_write);
}
int Protocol2PacketHandler::write2ByteTxRx(PortHandler *port, uint8_t id, uint16_t address, uint16_t data, uint8_t *error)
{
  uint8_t data_write[2] = { MCY_LOBYTE(data), MCY_HIBYTE(data) };
  return writeTxRx(port, id, address, 2, data_write, error);
}
 
int Protocol2PacketHandler::write4ByteTxOnly(PortHandler *port, uint8_t id, uint16_t address, uint32_t data)
{
  uint8_t data_write[4] = { MCY_LOBYTE(MCY_LOWORD(data)), MCY_HIBYTE(MCY_LOWORD(data)), MCY_LOBYTE(MCY_HIWORD(data)), MCY_HIBYTE(MCY_HIWORD(data)) };
  return writeTxOnly(port, id, address, 4, data_write);
}
int Protocol2PacketHandler::write4ByteTxRx(PortHandler *port, uint8_t id, uint16_t address, uint32_t data, uint8_t *error)
{
  uint8_t data_write[4] = { MCY_LOBYTE(MCY_LOWORD(data)), MCY_HIBYTE(MCY_LOWORD(data)), MCY_LOBYTE(MCY_HIWORD(data)), MCY_HIBYTE(MCY_HIWORD(data)) };
  return writeTxRx(port, id, address, 4, data_write, error);
}
 
int Protocol2PacketHandler::regWriteTxOnly(PortHandler *port, uint8_t id, uint16_t address, uint16_t length, uint8_t *data)
{
  int result                  = COMM_TX_FAIL;
 
  uint8_t *txpacket           = (uint8_t *)malloc(length + 12 + (length / 3));
 
  if (txpacket == NULL)
    return result;
  
  txpacket[PKT_ID]            = id;
  txpacket[PKT_LENGTH_L]      = MCY_LOBYTE(length+5);
  txpacket[PKT_LENGTH_H]      = MCY_HIBYTE(length+5);
  txpacket[PKT_INSTRUCTION]   = INST_REG_WRITE;
  txpacket[PKT_PARAMETER0+0]  = (uint8_t)MCY_LOBYTE(address);
  txpacket[PKT_PARAMETER0+1]  = (uint8_t)MCY_HIBYTE(address);
 
  for (uint16_t s = 0; s < length; s++)
    txpacket[PKT_PARAMETER0+2+s] = data[s];
 
  result = txPacket(port, txpacket);
  port->is_using_ = false;
 
  free(txpacket);
  return result;
}
 
int Protocol2PacketHandler::regWriteTxRx(PortHandler *port, uint8_t id, uint16_t address, uint16_t length, uint8_t *data, uint8_t *error)
{
  int result                  = COMM_TX_FAIL;
 
  uint8_t *txpacket           = (uint8_t *)malloc(length + 12 + (length / 3));
  uint8_t rxpacket[11]        = {0};
 
  if (txpacket == NULL)
    return result;
  
  txpacket[PKT_ID]            = id;
  txpacket[PKT_LENGTH_L]      = MCY_LOBYTE(length+5);
  txpacket[PKT_LENGTH_H]      = MCY_HIBYTE(length+5);
  txpacket[PKT_INSTRUCTION]   = INST_REG_WRITE;
  txpacket[PKT_PARAMETER0+0]  = (uint8_t)MCY_LOBYTE(address);
  txpacket[PKT_PARAMETER0+1]  = (uint8_t)MCY_HIBYTE(address);
 
  for (uint16_t s = 0; s < length; s++)
    txpacket[PKT_PARAMETER0+2+s] = data[s];
 
  result = txRxPacket(port, txpacket, rxpacket, error);
 
  free(txpacket);
  return result;
}
 
int Protocol2PacketHandler::syncReadTx(PortHandler *port, uint16_t start_address, uint16_t data_length, uint8_t *param, uint16_t param_length)
{
  int result                  = COMM_TX_FAIL;
 
  uint8_t *txpacket           = (uint8_t *)malloc(param_length + 14 + (param_length / 3));
  // 14: HEADER0 HEADER1 HEADER2 RESERVED ID LEN_L LEN_H INST START_ADDR_L START_ADDR_H DATA_LEN_L DATA_LEN_H CRC16_L CRC16_H
 
  if (txpacket == NULL)
    return result;
  
  txpacket[PKT_ID]            = BROADCAST_ID;
  txpacket[PKT_LENGTH_L]      = MCY_LOBYTE(param_length + 7); // 7: INST START_ADDR_L START_ADDR_H DATA_LEN_L DATA_LEN_H CRC16_L CRC16_H
  txpacket[PKT_LENGTH_H]      = MCY_HIBYTE(param_length + 7); // 7: INST START_ADDR_L START_ADDR_H DATA_LEN_L DATA_LEN_H CRC16_L CRC16_H
  txpacket[PKT_INSTRUCTION]   = INST_SYNC_READ;
  txpacket[PKT_PARAMETER0+0]  = MCY_LOBYTE(start_address);
  txpacket[PKT_PARAMETER0+1]  = MCY_HIBYTE(start_address);
  txpacket[PKT_PARAMETER0+2]  = MCY_LOBYTE(data_length);
  txpacket[PKT_PARAMETER0+3]  = MCY_HIBYTE(data_length);
 
  for (uint16_t s = 0; s < param_length; s++)
    txpacket[PKT_PARAMETER0+4+s] = param[s];
 
  result = txPacket(port, txpacket);
  if (result == COMM_SUCCESS)
    port->setPacketTimeout((uint16_t)((11 + data_length) * param_length));
 
  free(txpacket);
  return result;
}
 
int Protocol2PacketHandler::syncWriteTxOnly(PortHandler *port, uint16_t start_address, uint16_t data_length, uint8_t *param, uint16_t param_length)
{
  int result                  = COMM_TX_FAIL;
 
  uint8_t *txpacket           = (uint8_t *)malloc(param_length + 14 + (param_length / 3));
 
  if (txpacket == NULL)
    return result;
  
  txpacket[PKT_ID]            = BROADCAST_ID;
  txpacket[PKT_LENGTH_L]      = MCY_LOBYTE(param_length + 7); // 7: INST START_ADDR_L START_ADDR_H DATA_LEN_L DATA_LEN_H CRC16_L CRC16_H
  txpacket[PKT_LENGTH_H]      = MCY_HIBYTE(param_length + 7); // 7: INST START_ADDR_L START_ADDR_H DATA_LEN_L DATA_LEN_H CRC16_L CRC16_H
  txpacket[PKT_INSTRUCTION]   = INST_SYNC_WRITE;
  txpacket[PKT_PARAMETER0+0]  = MCY_LOBYTE(start_address);
  txpacket[PKT_PARAMETER0+1]  = MCY_HIBYTE(start_address);
  txpacket[PKT_PARAMETER0+2]  = MCY_LOBYTE(data_length);
  txpacket[PKT_PARAMETER0+3]  = MCY_HIBYTE(data_length);
 
  for (uint16_t s = 0; s < param_length; s++)
    txpacket[PKT_PARAMETER0+4+s] = param[s];
 
  result = txRxPacket(port, txpacket, 0, 0);
 
  free(txpacket);
  return result;
}
 
int Protocol2PacketHandler::synchronise (PortHandler *port, uint8_t id, uint8_t *error = 0)
{
  const uint8_t synchronise_enable  = 0x02;
  const uint8_t ADDR_MCY_CONTROL_ENABLE = 0x30;
  const uint8_t ADDR_MX_HARDWARE_STATUS_L = 0x6b;
 
  uint8_t mcy_hardware_status = 0;
  int mcy_comm_result = COMM_TX_FAIL;             // Communication result
 
  bool is_synchronising = false;
 
  do
  {
    mcy_comm_result = read1ByteTxRx(port, id, ADDR_MX_HARDWARE_STATUS_L, &mcy_hardware_status, error);
    if (mcy_comm_result != COMM_SUCCESS)
    {
      return mcy_comm_result;
    }
 
    if (mcy_hardware_status & 0x02) // motor not synchronised
    {
      if (is_synchronising)
      {
 
  #if defined(__linux__)
          usleep(1000000);
  #endif
          continue;
      }
 
      mcy_comm_result = write1ByteTxRx(port, id, ADDR_MCY_CONTROL_ENABLE, synchronise_enable, error);
      if (mcy_comm_result != COMM_SUCCESS)
      {
          return mcy_comm_result;
      }
      is_synchronising = true;
 
    }
  } while (mcy_hardware_status & synchronise_enable);
 
  return mcy_comm_result;
}