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Registers

This page documents all motor registers available in the DaMiao motor.

How it works?

Register Persistence (Write vs Store)

write and store are two different operations:

  • Write (write_register): update register value in RAM immediately (runtime only).
  • Store (store_parameters): persist current runtime register values to flash (survives power cycle).

Python API (damiao_motor/core/motor.py)

Use these methods on DaMiaoMotor:

# Write to register (RAM, immediate but NOT persistent)
motor.write_register(25, 20.0)  # KP_ASR

# Store current runtime parameters to flash (persistent)
motor.store_parameters()

Web GUI (Write vs Store)

  • Editing a register in the Web GUI performs a runtime write first.
  • Click Store Parameters to store current runtime values to flash.
  • In current implementation, changing register 7 (MST_ID) or 8 (ESC_ID) also triggers store automatically.

Register Parameters – Description, Value, Type, Action; Edit with Save/Cancel for RW registers

CLI

From current CLI implementation:

Command Write action (RAM) Store behavior (flash)
damiao set-motor-id Writes register 8 (ESC_ID) Yes (calls store_parameters())
damiao set-feedback-id Writes register 7 (MST_ID) Yes (calls store_parameters())
damiao set-can-timeout Writes register 9 (TIMEOUT, 1 register unit = 50 microseconds) Yes (calls store_parameters())

Other CLI control commands (send-cmd-*, set-zero-command, set-zero-position) do not call store, so parameter changes are not persisted.

CAN Baud Rate Codes

The CAN_BAUD_RATE_CODES dictionary maps baud rate codes to actual baud rates:

Code Baud Rate
0 125,000 (125K)
1 200,000 (200K)
2 250,000 (250K)
3 500,000 (500K)
4 1,000,000 (1M) 
from damiao_motor import CAN_BAUD_RATE_CODES

# Access baud rate codes
for code, baud_rate in CAN_BAUD_RATE_CODES.items():
    print(f"Code {code}: {baud_rate} bps")

Usage Examples

from damiao_motor import DaMiaoController

controller = DaMiaoController(channel="can0")
motor = controller.add_motor(motor_id=0x01, feedback_id=0x00, motor_type="4340")

# Read a specific register
value = motor.get_register(0x00)  # Read UV_Value

# Check if read was successful
if value is not None:
    print(f"Value: {value}")

# Write to a register (only RW registers can be written)
motor.write_register(7, 0x01)  # Set MST_ID to 1 (RAM)

# Store to keep the change after power cycle
motor.store_parameters()

from damiao_motor import REGISTER_TABLE

# Access register information
for register_id, info in REGISTER_TABLE.items():
    print(f"Register {register_id:2d} (0x{register_id:02X}): "
          f"{info.variable:12s} - {info.description} "
          f"[{info.access}]")

Safety Notes

Register Safety

  • Some registers affect motor behavior immediately
  • Always verify register values before writing
  • Read-only (RO) registers cannot be written
  • Refer to motor firmware documentation for detailed register behavior
  • Test register changes in a safe environment

Register Table

ID Variable Description Access Range Type
0 UV_Value Under-voltage protection value (see UNDER_VOLTAGE 0x9) RW (10.0, 3.4E38] float
1 KT_Value Torque coefficient \(K_T\) used in MIT mode RW [0.0, 3.4E38] float
2 OT_Value Over-temperature protection value (see MOS/ROTOR over-temp) RW [80.0, 200) float
3 OC_Value Over-current protection value (see OVER_CURRENT 0xA) RW (0.0, 1.0) float
4 ACC Acceleration RW (0.0, 3.4E38) float
5 DEC Deceleration RW [-3.4E38, 0.0) float
6 MAX_SPD Maximum speed RW (0.0, 3.4E38] float
ID Variable Description Access Range Type
7 MST_ID Feedback ID RW [0, 0x7FF] uint32
8 ESC_ID Receive ID RW [0, 0x7FF] uint32
9 TIMEOUT Timeout alarm time (1 register unit = 50 microseconds; see LOST_COMM 0xD) RW [0, 2^32-1] uint32
10 CTRL_MODE Control mode RW [1, 4] uint32
ID Variable Description Access Range Type
11 Damp Motor viscous damping coefficient RO / float
12 Inertia Motor moment of inertia RO / float
13 hw_ver Reserved RO / uint32
14 sw_ver Software version number RO / uint32
15 SN Reserved RO / uint32
16 NPP Motor pole pairs RO / uint32
17 Rs Motor phase resistance RO / float
18 Ls Motor phase inductance RO / float
19 Flux Motor flux linkage value RO / float
20 Gr Gear reduction ratio RO / float
ID Variable Description Access Range Type
21 PMAX Position mapping range RW (0.0, 3.4E38] float
22 VMAX Speed mapping range RW (0.0, 3.4E38] float
23 TMAX Torque mapping range RW (0.0, 3.4E38] float

PMAX / VMAX / TMAX Defaults

Registers 21 (PMAX), 22 (VMAX), and 23 (TMAX) are writable and can be changed with register writes (API/CLI/GUI).

Recommended Practice

These mapping limits should normally stay at their default motor-type values. The SDK uses motor-type presets in damiao_motor/core/motor.py (MOTOR_TYPE_PRESETS, built from _MOTOR_LIMIT_PARAM) for command encoding and feedback decoding. If motor register mapping limits are changed without keeping SDK limits consistent, command/feedback scaling can become inconsistent.

Default values in code (_MOTOR_LIMIT_PARAM):

Motor type PMAX VMAX TMAX
3507 12.566 50 5
4310 12.5 30 10
4310P 12.5 50 10
4340 12.5 10 28
4340P 12.5 10 28
6006 12.5 45 20
8006 12.5 45 40
8009 12.5 45 54
10010L 12.5 25 200
10010 12.5 20 200
H3510 12.5 280 1
G6215 12.5 45 10
H6220 12.5 45 10
JH11 12.5 10 12
6248P 12.566 20 120
ID Variable Description Access Range Type
24 I_BW Current loop control bandwidth RW [100.0, 10000.0] float
25 KP_ASR Speed loop Kp (used in POS_VEL, VEL, FORCE_POS) RW [0.0, 3.4E38] float
26 KI_ASR Speed loop Ki (used in POS_VEL, VEL, FORCE_POS) RW [0.0, 3.4E38] float
27 KP_APR Position loop Kp (used in POS_VEL, FORCE_POS) RW [0.0, 3.4E38] float
28 KI_APR Position loop Ki (used in POS_VEL, FORCE_POS) RW [0.0, 3.4E38] float
ID Variable Description Access Range Type
29 OV_Value Overvoltage protection value (see OVER_VOLTAGE 0x8) RW TBD float
30 GREF Gear torque efficiency RW (0.0, 1.0] float
31 Deta Speed loop damping coefficient RW [1.0, 30.0] float
32 V_BW Speed loop filter bandwidth RW (0.0, 500.0) float
ID Variable Description Access Range Type
33 IQ_c1 Current loop enhancement coefficient RW [100.0, 10000.0] float
34 VL_c1 Speed loop enhancement coefficient RW (0.0, 10000.0] float
ID Variable Description Access Range Type
35 can_br CAN baud rate code RW [0, 4] uint32
36 sub_ver Sub-version number RO / uint32
ID Variable Description Access Range Type
50 u_off U-phase offset RO - float
51 v_off V-phase offset RO - float
52 k1 Compensation factor 1 RO - float
53 k2 Compensation factor 2 RO - float
54 m_off Angle offset RO - float
55 dir Direction RO - float
ID Variable Description Access Range Type
80 p_m Motor position RO - float
81 xout Output shaft position RO - float