Edit on GitHub

Matlab Broadcast Ping Protocol 2.0

Sample code

%
% broadcast_ping.m
%
%  Created on: 2016. 6. 7.
%      Author: Ryu Woon Jung (Leon)
%

%
% *********     BroadcastPing Example      *********
%
%
% Available Dynamixel model on this example : All models using Protocol 2.0
% This example is designed for using a Dynamixel PRO 54-200, and an USB2DYNAMIXEL.
% To use another Dynamixel model, such as X series, see their details in E-Manual(support.robotis.com) and edit below variables yourself.
% Be sure that Dynamixel PRO properties are already set as %% ID : 1 / Baudnum : 3 (Baudrate : 1000000 [1M])
%

clc;
clear all;

% Load Libraries
if ~libisloaded('dxl_x86_c');
    [notfound, warnings] = loadlibrary('dxl_x86_c', 'dynamixel_sdk.h', 'addheader', 'port_handler.h', 'addheader', 'packet_handler.h');
end

% Protocol version
PROTOCOL_VERSION                = 2.0;          % See which protocol version is used in the Dynamixel

% Default setting
BAUDRATE                        = 1000000;
DEVICENAME                      = 'COM1';       % Check which port is being used on your controller
                                                % ex) Windows: 'COM1'   Linux: '/dev/ttyUSB0'

MAX_ID                          = 252;          % Maximum ID value
COMM_SUCCESS                    = 0;            % Communication Success result value
COMM_TX_FAIL                    = -1001;        % Communication Tx Failed

% Initialize PortHandler Structs
% Set the port path
% Get methods and members of PortHandlerLinux or PortHandlerWindows
port_num = portHandler(DEVICENAME);

% Initialize PacketHandler Structs
packetHandler();

dxl_comm_result = COMM_TX_FAIL;                 % Communication result

% Open port
if (openPort(port_num))
    fprintf('Succeeded to open the port!\n');
else
    unloadlibrary('dxl_x86_c');
    fprintf('Failed to open the port!\n');
    input('Press any key to terminate...\n');
    return;
end


% Set port baudrate
if (setBaudRate(port_num, BAUDRATE))
    fprintf('Succeeded to change the baudrate!\n');
else
    unloadlibrary('dxl_x86_c');
    fprintf('Failed to change the baudrate!\n');
    input('Press any key to terminate...\n');
    return;
end


% Try to broadcast ping the Dynamixel
broadcastPing(port_num, PROTOCOL_VERSION);
if getLastTxRxResult(port_num, PROTOCOL_VERSION) ~= COMM_SUCCESS
    printTxRxResult(PROTOCOL_VERSION, getLastTxRxResult(port_num, PROTOCOL_VERSION));
end

fprintf('Detected Dynamixel : \n');
for id = 0 : MAX_ID
  if getBroadcastPingResult(port_num, PROTOCOL_VERSION, id)
    fprintf('[ID:%03d]\n', id);
  end
end


% Close port
closePort(port_num);

% Unload Library
unloadlibrary('dxl_x86_c');

close all;
clear all;

Details

% Load Libraries
if ~libisloaded('dxl_x86_c');
    [notfound, warnings] = loadlibrary('dxl_x86_c', 'dynamixel_sdk.h', 'addheader', 'port_handler.h', 'addheader', 'packet_handler.h');
end

This example uses dynamixel library imported by loadlibrary().

% Protocol version
PROTOCOL_VERSION                = 2.0;          % See which protocol version is used in the Dynamixel

Dynamixel uses either or both protocols: Protocol 1.0 and Protocol 2.0. Choose one of the Protocol which is appropriate in the Dynamixel.

% Default setting
BAUDRATE                        = 1000000;
DEVICENAME                      = 'COM1';       % Check which port is being used on your controller
                                                % ex) Windows: 'COM1'   Linux: '/dev/ttyUSB0'

Here we set some variables to let you freely change them and use them to run the example code.

As the document previously said in previous chapter, customize Dynamixel control table items, such as Dynamixel ID, communication BAUDRATE, and the DEVICENAME, on your own terms of needs. In particular, BAUDRATE and DEVICENAME have systematical dependencies on your controller, so make clear what kind of communication method you will use.

MAX_ID                          = 252;          % Maximum ID value

Dynamixel ID can be set with in the range from 1 to 252

COMM_SUCCESS                    = 0;            % Communication Success result value
COMM_TX_FAIL                    = -1001;        % Communication Tx Failed

Each of the variables above show the meaning of the communication result value.

% Initialize PortHandler Structs
% Set the port path
% Get methods and members of PortHandlerLinux or PortHandlerWindows
port_num = portHandler(DEVICENAME);

portHandler() function sets port path as DEVICENAME and get port_num, and prepares an appropriate functions for port control in controller OS automatically. port_num would be used in many functions in the body of the code to specify the port for use.

% Initialize PacketHandler Structs
packetHandler();

packetHandler() function initializes parameters used for packet construction and packet storing.

dxl_comm_result = COMM_TX_FAIL;                 % Communication result

dxl_comm_result indicates which error has been occurred during packet communication.

% Open port
if (openPort(port_num))
    fprintf('Succeeded to open the port!\n');
else
    unloadlibrary('dxl_x86_c');
    fprintf('Failed to open the port!\n');
    input('Press any key to terminate...\n');
    return;
end

First, controller opens #port_num port to do serial communication with the Dynamixel. If it fails to open the port, the example will be terminated.

% Set port baudrate
if (setBaudRate(port_num, BAUDRATE))
    fprintf('Succeeded to change the baudrate!\n');
else
    unloadlibrary('dxl_x86_c');
    fprintf('Failed to change the baudrate!\n');
    input('Press any key to terminate...\n');
    return;
end

Secondly, the controller sets the communication BAUDRATE at #port_num port opened previously.

% Try to broadcast ping the Dynamixel
broadcastPing(port_num, PROTOCOL_VERSION);
if getLastTxRxResult(port_num, PROTOCOL_VERSION) ~= COMM_SUCCESS
    printTxRxResult(PROTOCOL_VERSION, getLastTxRxResult(port_num, PROTOCOL_VERSION));
end

broadcastPing() function shows the connection between controller and each DYNAMIXEL from ID 1 to ID 253 through #port_num port.

% Close port
closePort(port_num);

Finally, port becomes disposed.