This document defines how to communicate with the robot on the lowest level. This protocol is used by our native ROS, Python, C++ and C# drivers to abstract this communication away.
Communication Settings
Baud Rate: 57600
Parity: None
TX message format
Length: 7 bytes (56 bits)
start byte + left motor + right motor + flipper + parameter 1 + parameter 2 + checksum
start byte: 253
motors speeds: 0 - 250
0 is full speed reverse
125 is stop
250 is full speed forward
parameter 1: see appendix
parameter 2: see appendix
checksum: 255-( Left motor + right motor + flipper + parameter 1 + parameter 2)%255
RX message format
Length: 5 bytes (40 bits)
start byte + Data NO + data 1 + data 2 + checksum
start byte: 253
DataNO: Same as parameter 2 of TX message
data1: high byte of the data
data2: low byte of the data
checksum: 255-( Data NO + data 1 + data 2)%255
Appendix
Table 1 - TX Parameter 1
| Parameter 1 | Description |
| 10 | Request data with param 2 |
| 20 | Send fan speed with param 2 |
Table 2 - TX Parameter 2
| Param 2 | Description | Allowable data | Comments |
| 0 | REG_PWR_TOTAL_CURRENT | 0-2048, decimal, Actual unit to be tested, Theoretical value: a reading of 34 = 1A |
Total current from battery |
| 2 | REG_MOTOR_FB_RPM.left | N/A | Work in progress |
| 4 | REG_MOTOR_FB_RPM.right | N/A | Work in progress |
| 6 | REG_FLIPPER_FB_POSITION.pot1 | 0-1023, decimal, relative position of 15 - 330 degrees of one sensor | Flipper position sensor 1 |
| 8 | REG_FLIPPER_FB_POSITION.pot2 | 0-1023, decimal, relative position of 15 - 330 degrees of one sensor | Flipper position sensor 2 |
| 10 | REG_MOTOR_FB_CURRENT_left |
0-1023, decimal, Actual unit to be tested, Theoretical value: a reading of 34 = 1A |
Left motor current |
| 12 | REG_MOTOR_FB_CURRENT_right |
0-1023, decimal, Actual unit to be tested, Theoretical value: a reading of 34 = 1A |
Right motor current |
| 14 | REG_MOTOR_ENCODER_COUNT.left |
Unsigned 16 bit integer 0 - UINT16_MAX. May overflow or underflow. Increments when motor driven forward, decrements backward |
Left motor encoder count. |
| 16 | REG_MOTOR_ENCODER_COUNT.right |
Unsigned 16 bit integer 0 - UINT16_MAX. May overflow or underflow. Increments when motor driven forward, decrements backward |
Right motor encoder count |
| 18 | REG_MOTOR_FAULT_FLAG.left |
WIP |
Motor fault (work in progress, WIP) |
| 20 | REG_MOTOR_TEMP.left |
Decimal, celsius |
Left motor temperature |
| 22 | REG_MOTOR_TEMP.right |
Decimal, celsius |
Right motor temperature |
| 24 | REG_PWR_BAT_VOLTAGE.a |
0-1023, decimal, Actual unit to be tested, Theoretical value: a reading of 58 = 1V |
Voltage, battery side a |
| 26 | REG_PWR_BAT_VOLTAGE.b |
0-1023, decimal, Actual unit to be tested, Theoretical value: a reading of 58 = 1V |
Voltage, battery side a |
| 28 | EncoderInterval[0] |
Number of ticks between two adjacent rising edge signal from motor encoder |
Left motor, About 45 us/ Tick, for example, if a value of 100 is returned (100 ticks), then the time it takes to complete a full cycle is 4500 us = 45* 100. |
| 30 | EncoderInterval[1] |
Number of ticks between two adjacent rising edge signal from motor encoder |
Right motor, About 45 us/ Tick |
| 32 | EncoderInterval[2] |
Number of ticks between two adjacent rising edge signal from motor encoder |
Flipper motor, reserved for the future, not in use right now, About 45 us/ Tick |
| 34 | REG_ROBOT_REL_SOC_A |
% |
Battery relative state of charge, 0-100%, data range 0-100 decimal (WIP) |
| 36 | REG_ROBOT_REL_SOC_B |
% |
Battery relative state of charge, 0-100%, data range 0-100 decimal |
| 38 | REG_MOTOR_CHARGER_STATE |
See comments |
0xDADA meaning charging, otherwise, no battery charger state: 56026 |
| 40 | BuildNO |
See comments |
A + mon + date A= last digit of a year /2 mon=0x date=0x For example, a build on 05-09-2018 A=8/2=4 mon=05 date=09 Build=40509 |
| 42 | REG_PWR_A_CURRENT |
0-1023, decimal, Actual unit to be tested, Theoretical value: a reading of 34 = 1A |
Battery a current |
| 44 | REG_PWR_B_CURRENT |
0-1023, decimal, Actual unit to be tested, Theoretical value: a reading of 34 = 1A |
Battery b current |
| 46 | REG_MOTOR_FLIPPER_ANGLE |
0-360, degrees (actual data range needs to be tested) |
Flipper angle |
| 48 | to_computer_REG_MOTOR_SIDE_FAN_SPEED | 0-240, relative fan speed | Fan speed (feedback) |
| 50 | to_computer_REG_MOTOR_SLOW_SPEED |
0 or 1 0 - high speed (low speed off) 1 - low speed |
Low speed mode status (feedback) |
| 52 | BATTERY_STATUS_A | Bit flags |
Alarm bits: 0x8000 OVER_CHARGED_ALARM 0x4000 TERMINATE_CHARGE_ALARM 0x1000 OVER_TEMP_ALARM 0x0800 TERMINATE_DISCHARGE_ALARM 0x0200 REMAINING_CAPACITY_ALARM 0x0100 REMAINING_TIME_ALARM Status bits: 0x0080 INITIALIZED 0x0040 DISCHARGING 0x0020 FULLY_CHARGED 0x0010 FULLY_DISCHARGED |
| 54 | BATTERY_STATUS_B | Bit flags |
Alarm bits: 0x8000 OVER_CHARGED_ALARM 0x4000 TERMINATE_CHARGE_ALARM 0x1000 OVER_TEMP_ALARM 0x0800 TERMINATE_DISCHARGE_ALARM 0x0200 REMAINING_CAPACITY_ALARM 0x0100 REMAINING_TIME_ALARM Status bits: 0x0080 INITIALIZED 0x0040 DISCHARGING 0x0020 FULLY_CHARGED 0x0010 FULLY_DISCHARGED |
| 56 | BATTERY_MODE_A | Bit flags | Bit 7 (value & 0x80) gives whether battery needs a condition cycle. Other values probably useless |
| 58 | BATTERY_MODE_B | Bit flags | Bit 7 (value & 0x80) gives whether battery needs a condition cycle. Other values probably useless |
| 60 | BATTERY_TEMP_A | Temperature of battery above absolute 0 in deciKelvins | |
| 62 | BATTERY_TEMP_B | Temperature of battery above absolute 0 in deciKelvins | |
| 64 | BATTERY_VOLTAGE_A | Voltage of battery in mV | These are sampled from the SmartBattery itself, compare with PWR_BAT_VOLTAGE, which is estimated from a signal from the motor |
| 66 | BATTERY_VOLTAGE_B | Voltage of battery in mV | These are sampled from the SmartBattery itself, compare with PWR_BAT_VOLTAGE, which is estimated from a signal from the motor |
| 68 | BATTERY_CURRENT_A | Current of battery in mA | These are sampled from the SmartBattery itself, |
| 70 | BATTERY_CURRENT_B | Current of battery in mA | These are sampled from the SmartBattery itself, |