6-Axis Bus IMU Documentation

Introduction

A careful reading of the AX-12 manual is highly recommended, as it forms the baseline documentation for Bioloid bus devices.

Feature Overview

- can change the device ID (defaults to 120)
- can change baud rate, return delay time, status return level
- control table implementation (partly in EEPROM)
- updates IMU entries at 100 Hz

Control Table

EEPROM Table

Address	Item	Access	Initial Value
0 (0x00)	Model Number(L)	RD	10
1 (0x01)	Model Number(H)	RD	67
2 (0x02)	Firmware Version	RD	?
3 (0x03)	ID	RD,WR	120
4 (0x04)	Baud Rate	RD,WR	1
5 (0x05)	Return Delay Time	RD,WR	250
6 (0x06)	Reserved	-	0
7 (0x07)	Reserved	-	0
8 (0x08)	Reserved	-	0
9 (0x09)	Reserved	-	0
10 (0x0A)	Reserved	-	0
11 (0x0B)	Reserved	-	0
12 (0x0C)	Reserved	-	0
13 (0x0D)	Reserved	-	0
14 (0x0E)	Reserved	-	0
15 (0x0F)	Reserved	-	0
16 (0x10)	Status Return Level	RD,WR	2
17 (0x11)	Reserved	-	0
18 (0x12)	Reserved	-	0
19 (0x13)	Reserved	-	0
20 (0x14)	Reserved	-	0
21 (0x15)	Reserved	-	0
22 (0x17)	Reserved	-	0
23 (0x18)	Reserved	-	0

RAM Table

Address	Item	Access	Initial Value
24 (0x18)	Reserved	-	0
25 (0x19)	LED	RD,WR	0
26 (0x1A)	Sideways Accel(L)	RD	?
27 (0x1B)	Sideways Accel(H)	RD	?
28 (0x1C)	Forwards Accel(L)	RD	?
29 (0x1D)	Forwards Accel(H)	RD	?
30 (0x1E)	Vertical Accel(L)	RD	?
31 (0x1F)	Vertical Accel(H)	RD	?
32 (0x20)	Pitch Rate(L)	RD	?
33 (0x21)	Pitch Rate(H)	RD	?
34 (0x22)	Roll Rate(L)	RD	?
35 (0x23)	Roll Rate(H)	RD	?
36 (0x24)	Yaw Rate(L)	RD	?
37 (0x25)	Yaw Rate(H)	RD	?

---

Commands

The following commands are processed by this device:

Instruction	Function	Value	# of Parms
PING	No action. Used for obtaining a Status Packet	0x01	0
READ_DATA	Reading values in the Control Table	0x02	2
WRITE_DATA	Writing values to the Control Table	0x03	2+
RESET	Changes the control table values back to the Factory Default Values	0x06	0

The way these commands are used, including the way the checksum is generated and the contents of the return packet, is identical to the Robotis devices.

---

Sensors

The sensors on the board are these:

IMU 5 Degrees of Freedom
Gyro Breakout Board - ADXRS300 - 300 degree/sec

Those two pages have links to the individual sensor chip datasheets.