User Guide

Hardware Overview

BLE Role Selection

The device boots as a BLE Central device after POR by default. D1 will be BLUE.

Press and hold push button (SW1) during POR to boot as a BLE Peripheral Device. D1 will be GREEN.

BLE Central Role

LED States

BLE Peripheral Role

LED States

Unsolicited Data Characteristic

This characteristic is used to send telemetry data to the host via BLE notifications. Each 20-byte notification has the following format:

Packet ID 1 Data Bytes

This packet contains the raw IMU data and TOF distance measurement in mm (if active).

IMU Data Conversion

The following code snippets show how to convert the raw int16 accelerometer and gyroscope data to their respective units:

Packet ID 2 Data Bytes

This packet contains the motor current measurements in A.

BLE Commands

The following table outlines BLE commands supported by the Rover. Refer to respective section for more information.

**Legacy MotorHAT BLE commands.

Set Motor 1 Throttle

• Command: 0x0003

• Mailbox:

  • Byte 0:

    • Description: Motor Throttle

Set Motor 2 Throttle

• Command: 0x0004

• Mailbox:

  • Byte 0:

    • Description: Motor Throttle

Set Motor 1 and 2 Throttles

• Command: 0x0005

• Mailbox:

  • Byte 0:

    • Description: Motor 1 Throttle

Kill All Motors

• Command: 0x0007

• Command Response(s)

  • MDRDIOPROFILE_CMDRSP_SUCCESS

  • MDRDIOPROFILE_CMDRSP_FAILURE

Set Peripheral State

Enables/disables optional on-board/off-board peripherals.

• Command: 0x000D

• Mailbox:

  • Byte 0:

    • Description: Peripheral ID

Set Motor 3 Throttle

• Command: 0x0010

• Mailbox:

  • Byte 0:

    • Description: Motor Throttle

Set Motor 4 Throttle

• Command: 0x0011

• Mailbox:

  • Byte 0:

    • Description: Motor Throttle

Set Motor 3 and 4 Throttles

• Command: 0x0012

• Mailbox:

  • Byte 0:

    • Description: Motor 3 Throttle

Set All Motor Throttles

• Command: 0x0013

• Mailbox:

  • Byte 0:

    • Description: Motor 1 Throttle

Set All Motor Throttles (Finite)

• Command: 0x0014

• Mailbox:

  • Byte 0:

    • Description: Motor 1 Throttle

System Reset

Performs a power on reset (POR) after 1 second.

• Command: 0x0015

• Command Response(s)

  • MDRDIOPROFILE_CMDRSP_SUCCESS

  • MDRDIOPROFILE_CMDRSP_FAILURE

No Operation (NOP)

Does nothing. Can be used to poll telemetry data safely.

• Command: 0x0016

• Command Response(s)

  • MDRDIOPROFILE_CMDRSP_SUCCESS

Set Stick Dead Zones

Sets the dead zone for both the left and right sticks of the controller.

For example, if dead zone is set to 100 (dec), a stick value that falls within range -100 <= stick value <= +100 will be set to 0.

• Command: 0x0017

• Mailbox:

  • Bytes 0-1:

    • Description: Left Stick X Dead Zone (+/-)

Set Motor CSA Gains

Sets the gain of the Current Sense Amplifier (CSA) for each of the motor channels.

• Command: 0x0018

• Mailbox:

  • Byte 0:

    • Description: Motor 1 CSA Gain

Control Telemetry

This enables/disables telemetry data which consists of on-board sensor data and/or active, off-board peripherals (i.e. MODI) data.

If enabled, UART Command Response frames will contain sensor data. When device is in the Peripheral state and paired with via BLE, telemetry data will be sent in the form of BLE notifications via the Unsolicited Data characteristic. Refer to for more information.

If disabled, UART Command Response frame sensor data fields will be zero. No BLE notifications will be sent.

• Command: 0x0019

• Mailbox:

  • Byte 0:

    • Description: Enable/Disable

Command Response Codes

UART Interface

This section outlines the UART functionality of the device.

UART Settings

• Baud Rate: 115200

• Data Bit(s): 8

• Stop Bit(s): 1

• Parity: None

Host To RoverGen2: Command Frame Format

The Command frame consists of the 4-byte preamble (0xDEADBEEF), command ID, mailbox data and the 8-bit CRC, for a total of 27 bytes.

RoverHatGen2 To Host: Command Response Frame Format

The Command Response frame is solicited; it is generated on each received Command frame from the host.

It consists of the 4-byte preamble (0xDEADBEEF), the Command ID which generated the Command Response frame, the Response ID itself, IMU data, TOF distance data, and the 8-bit CRC, for a total of 23 39 bytes.

CRC Generation

The CRC appended to the Command and Command Response frames is an 8-bit XOR CRC:

The CRC is computed across the payload data of the frame, EXCLUDING the preamble.

For example: Bytes 4 to 25 of the Command Frame and bytes 4 to 21 of the Command Response Frame.

UART Interface Debug

Can be downloaded

Set Motor 1 and Motor 2 Throttles (Command 0x0005) Example

• Motor 1 Throttle: 50 %

• Motor 2 Throttle: -100%

Set All Motor Throttles (Command 0x0013) Example

Sets motors 1-4 to 100 % throttle.

Kill All Motors (Command 0x0007) Example

Set Motor 1 Throttle (Command 0x0003) Example

Sets motor 1 to 100 % throttle.

Set All Motor Throttles (Finite) (Command 0x0014) Example

• Motor 1: Unchanged

• Motor 2 : 100 % throttle for 5 seconds

• Motor 3: 50 % throttle, indefinately

• Motor 4: -25 % throttle for 10 seconds

System Reset (Command 0x0015) Example