===== ROSSerial Message Format =====

In RIC we only use the basic formatting of the ROSSerial protocol and not the publish/subscribe mechanism of ROS. In ROSSerial message formats are predefined and must be understood by both both RIC and the interface software.

A rosserial packet looks like this:

  1st Byte - Sync Flag (Value: 0xff)
  2nd Byte - Sync Flag / Protocol version
  3rd Byte - Message Length (N) - Low Byte
  4th Byte - Message Length (N) - High Byte
  5th Byte - Checksum over message length
  6th Byte - Topic ID - Low Byte
  7th Byte - Topic ID - High Byte
  x Bytes  - Serialized Message Data
  Byte x+1 - Checksum over Topic ID and Message Data

The ROSSerial format is described in more detail on the ROS wiki

Marty v2 ROSSerial interface

Marty 2 ROSSerial messages are different from Marty 1 and Marty 1 messages are not supported by Marty 2.

Publishers from Marty

Topic Name	Msg Type	Description
smart_servos Code: 120	SmartServo [] SmartServo: `uint8 IDNo` `int16 position` `int16 motorCurrent` `byte status`	An array of smart servo info each 6 bytes long IDNo is the index of the motor in the order described elsewhere with Left Hip == 0 position is an int16, same format as commanded positions, -32768 indicates an unknown value motorCurrent in milliamps, -32768 indicates an unknown value status byte is as reported by the servo
accel Code 121	marty_msgs/Accelerometer (`float32 x, float32 y, float32 z`)	The x,y,z of the built in accelerometer
power_status Code 122	uint8 `remCapPC` uint8 `tempDegC` uint16 `remCapMAH` uint16 `fullCapMAH` int16 `currentMA` uint16 `powerOnTimeSecs` uint16 powerFlags	Power status information Remaining capacity percentage (0..100) Battery temperature degC Remaining capacity mAh Battery fully charged mAh Current in mA, +ve means charging Time 5V has been on for in seconds Power Flags: bit 0 == on USB power bit 1 == 5V is turned on bit 2 == battery info is NOT valid bit 3 == USB power info is NOT valid
add_ons	AddOnInfo [] AddOnInfo: uint8 IDNo uint8 StatusFlags uint8 [10] RecentData	An array of add-on info each 12 bytes long IDNo is the IDNo of the add-on see hwstatus information for ordering but note this is dynamically allocated Status Flags: bit 7 (mask 0x80) indicates data is fresh (0 indicates stale) RecentData is the 10 bytes most recently read from the add-on during polling
robot_status (orginal 2 byte message) New 24 byte message: added to RIC Firmware in 2021 NOTE: martypy and other interfaces need to be able to cope with both message lengths	uint8 MotionFlags uint8 queueLen uint32 heapFree uint32 heapMin uint32 pix0_RGBT uint32 pix1_RGBT uint32 pix2_RGBT uint8 sysManLoopMsAvg uint8 sysManLoopMsMax	MotionFlags: bit 0 ROBOT_IS_MOVING bit 1 ROBOT_IS_PAUSED bit 2 FIRMWARE_UPDATE_IN_PROGRESS number of queued work items (255 indicates >=255) heap free space in bytes heap minimum (lower watermark) bytes RGBT means RGB (big endian) value in 1st 3 bytes and pixel state in last byte where 0 == off, 1 == on, 2 == breath, 3 == override average and max ms for SysManager loop (main service loop). 255 indicates >= 255

Topic Name

Msg Type

Description

smart_servos

Code: 120

SmartServo []

SmartServo:

uint8 IDNo

int16 position

int16 motorCurrent

byte status

An array of smart servo info each 6 bytes long

IDNo is the index of the motor in the order described elsewhere with Left Hip == 0

position is an int16, same format as commanded positions, -32768 indicates an unknown value

motorCurrent in milliamps, -32768 indicates an unknown value

status byte is as reported by the servo

accel

Code 121

marty_msgs/Accelerometer

(float32 x, float32 y, float32 z)

The x,y,z of the built in accelerometer

power_status

Code 122

uint8 remCapPC

uint8 tempDegC

uint16 remCapMAH

uint16 fullCapMAH

int16 currentMA

uint16 powerOnTimeSecs

uint16 powerFlags

Power status information

Remaining capacity percentage (0..100)

Battery temperature degC

Remaining capacity mAh

Battery fully charged mAh

Current in mA, +ve means charging

Time 5V has been on for in seconds

Power Flags:

bit 0 == on USB power

bit 1 == 5V is turned on

bit 2 == battery info is NOT valid

bit 3 == USB power info is NOT valid

add_ons

AddOnInfo []

AddOnInfo:

uint8 IDNo

uint8 StatusFlags

uint8 [10] RecentData

An array of add-on info each 12 bytes long

IDNo is the IDNo of the add-on see hwstatus information for ordering but note this is dynamically allocated

Status Flags:

bit 7 (mask 0x80) indicates data is fresh (0 indicates stale)

RecentData is the 10 bytes most recently read from the add-on during polling

robot_status

(orginal 2 byte message)

New 24 byte message: added to RIC Firmware in 2021

NOTE: martypy and other interfaces need to be able to cope with both message lengths

uint8 MotionFlags

uint8 queueLen

uint32 heapFree

uint32 heapMin

uint32 pix0_RGBT

uint32 pix1_RGBT

uint32 pix2_RGBT

uint8 sysManLoopMsAvg

uint8 sysManLoopMsMax

MotionFlags:

bit 0 ROBOT_IS_MOVING

bit 1 ROBOT_IS_PAUSED

bit 2 FIRMWARE_UPDATE_IN_PROGRESS

number of queued work items (255 indicates >=255)

heap free space in bytes

heap minimum (lower watermark) bytes

RGBT means RGB (big endian) value in 1st 3 bytes and pixel state in last byte where 0 == off, 1 == on, 2 == breath, 3 == override

average and max ms for SysManager loop (main service loop). 255 indicates >= 255