File content as of revision 13:ccda9a56fef1:

/**  
 * @file MX12.h
 * @brief this header file contains all required definitions and 
 *        basic utilities functions to manage au bus of servomotor 
 *        Dynaminel MX12
 */ 
#ifndef MBED_MX12_H_
#define MBED_MX12_H_

#include "mbed.h"

#define MX12_PACKET_MAX_SIZE 32
#define MX12_MAX_MOTOR_COUNT 16

/* Dynamixel protocol v1.0 : Instructions
 ******************************************/
#define PROTOCOL_INSTRUCTION_PING          0x01
#define PROTOCOL_INSTRUCTION_READ          0x02
#define PROTOCOL_INSTRUCTION_WRITE         0x03
#define PROTOCOL_INSTRUCTION_REG_WRITE     0x04
#define PROTOCOL_INSTRUCTION_ACTION        0x05
#define PROTOCOL_INSTRUCTION_FACTORY_RESET 0x06
#define PROTOCOL_INSTRUCTION_REBOOT        0x08
#define PROTOCOL_INSTRUCTION_SYNC_WRITE    0x83
#define PROTOCOL_INSTRUCTION_BULK_READ     0x92

/* Dynamixel protocol v1.0 : Contro table content
 ************************************************/
#define CONTROL_TABLE_MODEL_NUMBER            0
#define CONTROL_TABLE_FIRMWARE_VERSION        2 
#define CONTROL_TABLE_ID                      3
#define CONTROL_TABLE_BAUD_RATE               4
#define CONTROL_TABLE_RETURN_DELAY_TIME       5
#define CONTROL_TABLE_CW_ANGLE_LIMIT          6
#define CONTROL_TABLE_CCW_ANGLE_LIMIT         8
#define CONTROL_TABLE_TEMPERATURE_LIMIT      11
#define CONTROL_TABLE_MIN_VOLTAGE_LIMIT      12
#define CONTROL_TABLE_MAX_VOLTAGE_LIMIT      13
#define CONTROL_TABLE_MAX_TORQUE             14
#define CONTROL_TABLE_STATUS_RETURN_LEVEL    16
#define CONTROL_TABLE_ALARM_LED              17
#define CONTROL_TABLE_SHUTDOWN               18
#define CONTROL_TABLE_MULTITURN_OFFSET       20
#define CONTROL_TABLE_RESOLUTION_DIVIDER     22
#define CONTROL_TABLE_TORQUE_ENABLE          24
#define CONTROL_TABLE_LED                    25
#define CONTROL_TABLE_P_GAIN                 26
#define CONTROL_TABLE_I_GAIN                 27
#define CONTROL_TABLE_D_GAIN                 28
#define CONTROL_TABLE_GOAL_POSITION          30
#define CONTROL_TABLE_MOVING_SPEED           32
#define CONTROL_TABLE_TORQUE_LIMIT           34
#define CONTROL_TABLE_PRESENT_POSITION       36
#define CONTROL_TABLE_PRESENT_SPEED          38
#define CONTROL_TABLE_PRESENT_LOAD           40
#define CONTROL_TABLE_PRESENT_VOLTAGE        42
#define CONTROL_TABLE_PRESENT_TEMPERATURE    43
#define CONTROL_TABLE_REGISTRED_INSTRUCTION  44
#define CONTROL_TABLE_MOVING                 46
#define CONTROL_TABLE_LOCK                   47
#define CONTROL_TABLE_PUNCH                  48
#define CONTROL_TABLE_GOAL_ACCELERATION      73

/** 
 * @brief Class to communicate with Dynamixel MX12 servomotors
 *
 * @details
 *
 *  The servomotors are daisy chained to a serial link of the target 
 *  microcontroller. The class ensures the initialization of serial link 
 *  and the management of communications mainly to control rotational
 *  speed of servomotors. 
 *
 *  Transmission of messages to the servomotors is blocking while 
 *  reception is non-blocking thanks to the use of an interrupt routine. 
 * 
 * @author Titouan Soulard (creator and maintainer until April 2021)
 * @author Bruno Denis (Doxygen documentation and code rearrangement)
 *  
 * @see Control table of Dynamixel MX12 servomotor 
 * @see https://emanual.robotis.com/docs/en/dxl/mx/mx-12w/
 * @see Dynamixel protocol v1.0 manual
 * @see https://emanual.robotis.com/docs/en/dxl/protocol1/
 *
 * Example of class usage to send two instruction packets to servomotor #1
 * with one second gap. First ask to move at 10% of maximum speed and the 
 * stop the movement.
 *
 * @code
 * #include "mbed.h"
 * #include "MX12.h"
 * 
 * #define SERVO_TX_PIN PC_4
 * #define SERVO_RX_PIN PC_5
 * #define SERVO_BAUD 115200
 * #define SERVO_ID 1
 * 
 * #define DELAY_1000ms 1000
 * #define DELAY_1ms       1
 * 
 * MX12 servo_bus(SERVO_TX_PIN, SERVO_RX_PIN, SERVO_BAUD);
 * float relative_speed;
 * 
 * int main()
 * {
 *     // Set speed of SERVO_ID servomotor to 10% 
 *     // Send on servo_bus to SERVO_ID motor the instruction "moving speed"
 *     // with parameter 0.1 (10% of maximum speed)
 *     relative_speed = 0.1; 
 *     servo_bus.SetSpeed(SERVO_ID, relative_speed);
 *         
 *     // wait for one second
 *     thread_sleep_for(DELAY_1000ms);
 *     
 *     // set speed of SERVO_ID servomotor to 0% 
 *     relative_speed = 0.0; 
 *     servo_bus.SetSpeed(SERVO_ID, relative_speed);
 * 
 *     // infinite loop 
 *     while (true) thread_sleep_for(DELAY_1000ms);
 * }
 * @endcode
 *
 * @warning
 *
 *   Error field of status packet if decoded by GetStatus() 
 *   Doxygen Release 1.7.2 returns an enumation type "Status". As several 
 *   errors can be reported simultaneously the type enum is not suitable 
 *   (B. Denis 11/2021).
 *
 * @bug
 *
 *   Bug: GetStatus() method has a hazardous behavior because it provides 
 *   a result by reading the content of the variable _current_frame 
 *   which can be modified at any time by the private ISR _Rx_interrupt().
 *    
 */
class MX12 
{
    public:
    
    /** Error status occurred during the operation of servomotor.
     *
     * @warning 
     *    Enumaration type is not suitable for all error status because
     *    it can denote only one error at a time (B. Denis 11/2021)
     */
    enum Status {
        InstructionError,  /**<  In case of sending an undefined instruction 
                                 or delivering the action instruction 
                                 without the Reg Write instruction */
        OverloadError,     /**<  When the current load cannot be controlled 
                                 by the set Torque */
        ChecksumError,     /**<  When the Checksum of the transmitted 
                                 Instruction Packet is incorrect */
        RangeError,        /**<  When an instruction is out of the range 
                                 for use */
        OverheatingError,  /**<  When internal temperature of servomotor 
                                 is out of the range of operating 
                                 temperature set in the Control table */
        AngleLimitError,   /**<  When Goal Position is written out of the 
                                 range from CW Angle Limit to CCW Angle 
                                 Limit */
        InputVoltageError, /**<  When the applied voltage is out of the 
                                 range of operating voltage set in the 
                                 Control table */
        Unknown,           /**<  Combination of several errors (Caution: 
                                 limit of enum approach to code errors) */
        Ok                 ///<  no error
    };
    
    /** Enumeration of states of the medium acces control (MAC) 
     *  of the master-slave protocol of the communication between  
     *  the robot controller (master) and the servomotors (slaves).
     */
     enum SerialState {
        Writing, /**< Robot controller send an "instruction packet"
                      (request) to a servomotor */
        Reading, /**< Robot controller receive a "status packet" from a 
                      requested servomotor */
        Idle     ///< Robot controller ready for a new cycle request-answer 
    };
    
    /** Structure of store status packet (also known as return packet)
     *  according tne Dynamixel protocol v1.0, which are messages sent
     *  by servomotors to contriller in response of an instruction packet
     */
    struct Status_packet {
        unsigned char raw[MX12_PACKET_MAX_SIZE]; /**< bytes received */
        unsigned char n_byte;   /**< Number of received byte */
        unsigned char servo_id; /**< Identifier field denoted servomotor  
                                 *   involved in the message */
        unsigned char length;   /**< Length field of status packet */
        unsigned char error;    /**< Error field of status packet */
        unsigned char n_param;  /**< Number of received parameter*/
        unsigned char param[MX12_PACKET_MAX_SIZE]; /**< array of received
                                                    *   parameters */
        unsigned char received_checksum; /**< Received checksum field */
        unsigned char calculated_checksum; /**< Calculated checksum  */
        bool parsed;  /**< status packet is correctly parsed */
        bool valid;   /**< received_checksum == calculated_checksum */
    };

    /** 
     * @brief  Discrete states of the packet parser.
     *
     * @detail 
     *    Each value corresponding to a field that the parser 
     *    can identify according the Dynamixel protocol v1.0.
     *    Enumeration include field of instruction packets
     *    (packets sent to servomotors) and field of status packets
     *    (packets received from servomotors).
     */
    enum PacketField {
        Header1,     ///< Heading1 field of instruction or status packet
        Header2,     ///< Heading2 field of instruction or status packet
        Id,          ///< ID field of instruction or status packet
        Length,      ///< Length field of status packet
        Error,       ///< Error status field of status packet
        Instruction, ///< Instruction field of instruction packet
        Data,        ///< expect to read parameter fields of status packet
        Checksum     ///< expect to read Checksum field of status packet
    };

    /** Structure to store the current state of packet parserComplement to the ParsingState enumeration to store the reading 
     *  progress of each section of the status packet.
     */
    struct ParserState {
        MX12::PacketField expected_field; ///< next expected field
        unsigned char byte_index;  ///< index of byte already parsed
        unsigned char param_index; ///< index of parameter already parsed
    };

    /** Create MX12 instance
     *
     * @param tx board pin used for transmission in UART daisy chain link 
     *           to servomotors 
     * @param rx board pin used for reception in UART daisy chain link 
     *           to servomotors 
     * @param baud modulation rate of UART signal, unit: Baud
     *           to servomotors 
     */
    MX12(PinName tx, PinName rx, int baud=115200);
    
    /** Send desired speed to a specific servomotor
     *
     * @param mot_id a unique value in the daisy chain network to identify
     *               each servomotor
     * @param speed a float between -1 and 1 that represents the percentage
     *              of maximum requested speed
     */
    void SetSpeed(unsigned char mot_id, float speed);
    
    /** Informs about the availability of the bus for a new transmission 
     *  of instruction packet (Method Access Control) 
     *
     * @returns true if bus ready for a new transmission, otherwise false
     */
    char IsAvailable(void);
    
    /**
     * @brief     Build and send an instruction packet to a servomotor 
     *            according Dynamixel Protocol 1.0
     *
     * @detail    This method is limited to only two kind of instruction :
     *            read data from a servomoteur et write data on servomotor.
     *            Ping, Reg Write, Action, Factory Reset, Rebbot, Sync Write
     *            and Bulk Read are not supported.
     *
     *            For the method to issue a read instruction, set the data 
     *            parameter to NULL, otherwise the method issue a 
     *            write instruction 
     *
     * @param[in] mot_id indicates the ID of the device (servomotor) that
     *            should receive the Instruction Packet and process it
     * @param[in] address data address in the "Control Table of RAM Area"
     *            of a servomotor MX12 
     *            (https://emanual.robotis.com/docs/en/dxl/mx/mx-12w/#control-table-of-ram-area).
     * @param[in] len if it is a write instruction, size in bytes 
     *            of the data to write in the "Control Table of RAM Area"
     * @param[in] data array of char containing parameter of Danamixel  
     *            protocol that are the instruction’s auxiliary data field.
     *            Set to NULL for read instruction, otherwise the method issue 
     *            a write instruction 
     *  
     * @see https://emanual.robotis.com/docs/en/dxl/protocol1/
     *
     * Structure of instruction Packet
     *
     * <PRE>
     * |Header1|Header2|Packet ID|Length|Instruction|Param1...ParamN|Checksum|
     * |-------|-------|---------|------|-----------|---------------|--------|
     * |  0xFF |  0xFF |Packet ID|Length|Instruction|Param1...ParamN| CHKSUM |
     * | cmd[0]| cmd[1]|  cmd[2] |cmd[3]|  cmd[4]   |cmd[5]...      |        |
     *                  \\__  ___/                    \\_  _/ \\__  __/
     *                     \/                          \/      \/
     *                   mot_id                      address   data
     *                                                        (len = N-1)
     * </PRE>
     */
    void rw(unsigned char mot_id, char address, char len, char *data);
    
    /** 
     * Display status packet in hexadecimal format
     * 
     * @warning
     *    Use console without any previous declaration. Assume console is 
     *    setup by calling program
     */
    void PrintSerial();
    
    /**
     * Get information from de Error byte of the last status packet
     * received from a servomotor
     *
     * @return 
     *    One of enum MX12::Status value to describe errors. 'Ok' is
     *    returns if no error occurred during the last operation of
     *    servomotor.
     * 
     * @warning 
     *
     *    Warning: if a combination of several errors is reported the function
     *    returns 'Unknown' (B. Denis 11/2021).
     *
     * @bug
     *
     *    Bug: this method has a hazardous behavior because it provides 
     *    a result by reading the content of the variable _current_frame 
     *    which can be modified at any time by the private ISR _Rx_interrupt()  
     */
    MX12::Status GetStatus(void);

    /* function aivailaible in a previous version of the class 
     */
    // MX12::Status GetStatus(void);
    // void ReadPosition(unsigned char mot_id);
    // float GetPosition(unsigned char mot_id);
                
    protected:
    
    /** Serial port where servomotor bus is connected
     */
    UnbufferedSerial _mx12;
    
    
    /** Servomotor bus state to managed medium acces control (MAC)
     */
    MX12::SerialState _bus_state;
    
    /** Structure filled by ISR (Interrupt Service Routine) ReadCallback()
     *  parser to store message received from servomotor byte after byte 
     */
    MX12::Status_packet _status_pck;
    
    /** Structure update by ISR (Interrupt Service Routine) ReadCallback()
     *  parser to model its current state
     */
    MX12::ParserState _parser_state;

            
    unsigned char _answer;
                
    /** 
     * @brief  
     *    Interupt service routine (ISR) to read and parse received message
     *
     * @detail
     *
     *    This interupt routine is attached to reception event on servomoteur 
     *    bus and is called for each character received on bus. 
     *
     *    As the characters are received, the progress of the parser 
     *    is stored in _parser_state and the result of the analysis 
     *    is stored in _status_pck.
     */
    void _Rx_interrupt();
    
};

#endif /* MBED_MX12_H_ */