EtherCAT Communication Protocol

1. Equipment Basic Information

Field	Content
Device Name	BrainCo-Revo2Slave
Vendor Name	BrainCo
Vendor ID	0x00BC0000
Product Code	0x00009252
Revision No	0x00000001

• Specific object dictionary configuration

2.Synchronization Manager and PDO Mapping

2.1 Synchronization Manager Configuration

SM Index	Function	Corresponding PDO Index
SM2 (0x1C12)	Master → Slave Output	0x1600
SM3 (0x1C13)	Slave → Master Input	0x1A00

2.2 RxPDO（0x1600）

Subindex	Objects	Description
0x01	0x7000:01	Multiple finger control modes
0x02	0x7000:02	Multiple finger control parameters1（6xINT16）
0x03	0x7000:03	Multiple finger control parameters2（6xUINT16）
0x04	0x7010:01	Single finger control mode
0x05	0x7010:02	Single finger target joint ID
0x06	0x7010:03	Single finger control parameter1（INT16）
0x07	0x7010:04	Single finger control parameter2（UINT16）

Control mode definition

# define CTRL_MODE_POS_TIME   0x01  // Position + Time control
# define CTRL_MODE_POS_SPD    0x02  // Position + Speed control
# define CTRL_MODE_SPD        0x03  // Speed control
# define CTRL_MODE_CURRENT    0x04  // Current control
# define CTRL_MODE_PWM        0x05  // PWM duty cycle

Target Joint ID Definition

typedef enum {
    // 拇指尖部
    THUMB_FLEX,
    // 拇指根部
    THUMB_ABDUCT,
    // 食指
    INDEX_FINGER,
    // 中指
    MIDDLE_FINGER,
    // 无名指
    RING_FINGER,
    // 小指
    PINKY
} finger_index_t;

2.3 Finger TxPDO（0x1A00）

Subindex	Objects	Description
0x01	0x6000:01	Joint position（6xUINT16）
0x02	0x6000:02	Joint speed（6xINT16）
0x03	0x6000:03	Joint current（6xINT16）
0x04	0x6000:04	Joint status（6xUINT16）

• Position of 6 finger motors (Pos) → UINT16 ×6
• Speed of 6 finger motors (Spd) → INT16 ×6
• Current of 6 finger motors (Cur) → INT16 ×6
• Status of 6 finger motors (State) → UINT16 ×6
• Total: 48 bytes. The master station can map these directly to variables.

2.4 Capacitive Tactile TxPDO Dictionary（0x6010）

Index	Sub-index	Field Name	Type	Quantity	Description
0x6010	0x01	force_normal	UINT16	5	Normal force
0x6010	0x02	force_tangential	UINT16	5	Tangential force
0x6010	0x03	force_direction	UINT16）	5	Direction of tangential force
0x6010	0x04	proximity	UINT32	5	Proximity value
0x6010	0x05	touch_status	UINT16	5	Tactile state

• Normal force of 5 fingers (force_normal) → UINT16 ×5

• Tangential force of 5 fingers (force_tangential) → INT16 ×5

• Tangential force direction of 5 fingers (force_direction) → INT16 ×5

• Proximity value of 5 fingers (proximity) → UINT32 ×5

• Tactile status of 5 fingers (touch_status) → UINT16 ×5

• Total: 60 bytes. The master station can map these directly to variables.

• Normal and tangential forces are 16-bit unsigned data. The unit is 0.01 N, so a value of 1000 represents 10 N (1000 * 0.01 N). The measurement range is from 0 to 25 N.

• The direction of the tangential force is 16-bit unsigned data. The unit is in degrees, with a range of 0 to 359 degrees. The direction near the fingertip is 0 degrees, rotating clockwise up to a maximum of 359 degrees. When the value is 65535 (0xFFFF), it indicates an invalid tangential force direction.

• Proximity value is 32-bit unsigned data.

• The tactile status register is 16 bits, divided into high and low bytes representing different information:

  • Upper 8 bits: Indicate the packet sequence number for the sensor's internal data updates. If this value increases or changes, it means data has been updated.
  • Lower 8 bits: Indicate the sensor's current status. The bits are defined as follows:
    1. Bit 0: Original value is invalid.
    2. Bit 1: Original value has not been updated for a prolonged period.
    3. Bit 2: Trigger timeout.

3.Configuration parameter dictionary（Object 0x8000）

3.1 General configuration fields

Subindex	Parameter Name	Type	Description
0x01	hand_type	UINT8(WR)	0=left hand，1=right hand
0x02	led_switch	UINT8(WR)	Back of hand light switch
0x03	buzzer_switch	UINT8(WR)	Buzzer switch
0x04	vibrator_switch	UINT8(WR)	Vibrating motor switch
0x05	unit_mode	UINT8(WR)	0=Dimensionless, 1=Physical unit
0x06	pos_calibration	UINT8 (WO)	Manual position calibration
0x07	auto_calibration	UINT8(WR)	Automatic calibration on startup
0x08	turbo_mode	UINT8(WR)	Turbo
0x09	turbo_param[0] ，turbo_param[1]	2XUINT16(WR)	Turbo

3.2 Current field for protecting each joint

Subindex	Parameter Name	Type	Description
0x0A	thumb_flex_pro_cur	UINT16(WR)	Thumb flex protects current
0x0B	thumb_aux_pro_cur	UINT16(WR)	Thumb abduct protection current
0x0C	index_pro_cur	UINT16(WR)	Index finger protection current
0x0D	mid_pro_cur	UINT16(WR)	Middle finger protection current
0x0E	ring_pro_cur	UINT16(WR)	Ring finger protective current
0x0F	pink_pro_cur	UINT16(WR)	Little finger protection current
0x10	thumb_aux_lock_cur	UINT16(WR)	Thumb abduct joint locking current

3.3 Firmware information field

Subindex	Parameter Name	Type	Description
0x11	ctrl_wrist_fw_version	STRING(20)(RO)	Control board firmware version (string: high.mid.low)
0x12	ctrl_sn	STRING(18)(WR)	Control panel device serial number（SN）
0x13	wrist_fw_version	STRING(20)(RO)	Wristband firmware version (string: high, medium, low)
0x14	wrist_sn	STRING(18)(WR)	Wrist brace device serial number（SN）
0x15	foe_file_type	UINT8(WO)	FoE File type identifier: 1=Wrist board, 2=Control board
0x16	foe_auth_code	STRING(8)(WO)	FoE Document authentication code

4.Tactile SDO Parameter Dictionary（Object 0x8010）

Index	Sub-index	Field Name	Type	Length	Description
0x8010	1	thumb_calibration	uint8（WO）	1	Thumb Calibration
0x8010	2	index_calibration	uint8（WO）	1	Index finger calibration
0x8010	3	mid_calibration	uint8（WO）	1	Middle Finger Calibration
0x8010	4	ring_calibration	uint8（WO）	1	Ring Finger Calibration
0x8010	5	pinky_calibration	uint8（WO）	1	Pinky Calibration
0x8010	6	touch_vendor	uint8（RO）	1	Tactile manufacturer（1：Capacitive 2：pressure-sensitive）
0x8010	7	thumb_acq_param_update	uint8（WO）	1	Thumb channel value adjustment
0x8010	8	index_acq_param_update	uint8（WO）	1	Index finger channel value adjustment
0x8010	9	mid_acq_param_update	uint8（WO）	1	Middle finger channel value adjustment
0x8010	10	ring_acq_param_update	uint8（WO）	1	Ring finger channel value adjustment
0x8010	11	prink_acq_param_update	uint8（WO）	1	Little finger channel value adjustment
0x8010	12	reserved1	uint8（RO）	1	Reserved
0x8010	13	thumb_touch_fw_version	string（RO）	20	Thumb tactile firmware version
0x8010	14	index_touch_fw_version	string（RO）	20	Index Finger tactile Firmware Version
0x8010	15	mid_touch_fw_version	string（RO）	20	Middle finger tactile firmware version
0x8010	16	ring_touch_fw_version	string（RO）	20	Ring finger tactile firmware version
0x8010	17	pink_touch_fw_version	string（RO）	20	Pinky Finger Tactile Firmware Version

5. Control Mode and Parameter Description

The dexterous hand control protocol supports individual and simultaneous control of the 6 finger joints. The supported control methods include position, speed, current, and PWM duty cycle. These methods adapt to both normalized (percentage) and physical unit modes. Sign indicates direction: positive values for closing (bending) direction, and negative values for opening (straightening) direction.

5.1 Control mode number (suitable for single/multi-finger control)

Control Mode Number	Mode Name	param1 Description	param2 Description
0x01	Position + Time control	Target position	Exercise time（ms）
0x02	Position + Speed control	Target position	Movement speed
0x03	Speed Control	Target Speed	None
0x04	Current Control	Target Current	None
0x05	PWM Duty Cycle Control	PWM Ratio	None

5.2 PWM Control Instructions

• The PWM duty cycle is a unitless ratio, range -1000 ~ +1000

5.3 Unit mode explanation

a）Percentage mode（unit_mode = 0）

Parameter	Meaning	Range
Position	Percentage of itinerary	0 ~ 1000
Speed	Percentage of maximum speed	-1000 ~ 1000
Current	Percentage of maximum current (1000mA)	-1000 ~ 1000

b）Physical quantity mode（unit_mode = 1）

Parameter	Meaning	Unit
Location	Finger angle position	°
Speed	Finger angular velocity	°/s
Current	Actual motor control current	mA

5.4 Difference between multi-finger control and single-finger control

Type	Address Area	Control Mode Field	Control Parameter Structure
Multi finger control	RxPDO 0x7000	mult_finger_ctrl_mode	param1[6] + param2[6]
Single finger control	RxPDO 0x7010	finger_ctrl_mode	finger_id + param1 + param2

• Multi-finger control sets the target for all 6 fingers at once
• Single-finger control is used for precise adjustments or debugging of a single finger

6. FoE Firmware Upgrade Protocol Description

Revo 2 Pro and Touch version of the dexterous hand support firmware upgrades via the EtherCAT FoE (File over EtherCAT) protocol, suitable for the independent upgrade needs of the wrist board and control board.

6.1 Upgrade type and certification information

Upgrade Type	File Name	Upgrade Authentication Code
Wrist board firmware	Revo2EC_x.x.x_$time.bin	BRCW2025
Control board firmware	Revo2_Vx.x.x_$time.bin	BRCC2025

6.2 FoE Upgrade process

The complete FoE upgrade process includes four steps: authentication, defining the firmware type, transferring the firmware, and writing it to flash:

1. Master station writes the upgrade type and authentication code

• SDO 0x8000:0x15: Write upgrade type (1 = wrist board, 2 = control board)
• SDO 0x8000:0x16: Write authentication code (e.g., "BRCW2025")

2. Master station sends the firmware file via FoE

• The file name must exactly match the expected value (e.g., Revo2EC_0.0.1_2506231346.bin).

3. Slave station reception and verification

• Check if the authentication code matches.
• Write firmware to the corresponding Flash partition.

4. Upgrade Completed

• It is recommended that the master station resets the device or rescan the EtherCAT bus.

6.3 Precautions

• The file name is case-sensitive and must match exactly.
• PDO communication will be interrupted during the flash writing process.
• The device will automatically restart with the new firmware after the upgrade is completed.
• It is recommended to restart the EtherCAT bus after the upgrade finishes.

6.4 Upgrade timing diagram

6.5 Firmware file header structure

To ensure the legality and version identification of the firmware upgrade files.，All .bin files upgraded through FoE，The following header structure has been automatically added by the packaging tool.（A total of 16 bytes）：

Field Name	Length	Description
Magic Number	8 bytes	Fixed identifier used to identify device type: wrist board → "BRCW2025" Control panel → "BRCC2025"
Firmware Version	4 bytes	The structure of the firmware version number is as follows: The highest byte is a reserved field.（0x00）， The last three bytes correspond to the major version number.（Major）、 Minor version number（Minor）、Revision number（Patch）。 For example, the version number 1.2.3 Represented as：0x00010203
Reserved field	4 bytes	Reserved field, currently 0x00, reserved for future expansion.

This structure is automatically written to the file header by the packaging tool, and users do not need to add it manually, nor should they modify it.

** Upgrade Verification Logic**

• After the FoE file is received, first check if the Magic Number matches the current upgrade type;
• If it does not match, the upgrade is rejected; if it matches, proceed to the burning process.
• The firmware header data is used for upgrade determination and will not be written into the Flash application area.