Bioloid IO Board 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 122)
- can change baud rate, return delay time, status return level
- control table implementation (partly in EEPROM)
- updates control table entries at 100 Hz

Control Table

EEPROM Table

Address	Item	Access	Initial Value
0 (0x00)	Model Number(L)	RD	12
1 (0x01)	Model Number(H)	RD	68
2 (0x02)	Firmware Version	RD	?
3 (0x03)	ID	RD,WR	122
4 (0x04)	Baud Rate	RD,WR	1
5 (0x05)	Return Delay Time	RD,WR	250
6 (0x06)	Digital Port 0 Direction	RD,WR	0
7 (0x07)	Digital Port 1 Direction	RD,WR	0
8 (0x08)	Digital Port 2 Direction	RD,WR	0
9 (0x09)	Digital Port 3 Direction	RD,WR	0
10 (0x0A)	PWM Type	RD,WR	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)	ADC Port 0 (L)	RD	?
27 (0x1B)	ADC Port 0 (H)	RD	?
28 (0x1C)	ADC Port 1 (L)	RD	?
29 (0x1D)	ADC Port 1 (H)	RD	?
30 (0x1E)	ADC Port 2 (L)	RD	?
31 (0x1F)	ADC Port 2 (H)	RD	?
32 (0x20)	ADC Port 3 (L)	RD	?
33 (0x21)	ADC Port 3 (H)	RD	?
34 (0x22)	ADC Port 4 (L)	RD	?
35 (0x23)	ADC Port 4 (H)	RD	?
36 (0x24)	ADC Port 5 (L)	RD	?
37 (0x25)	ADC Port 5 (H)	RD	?
38 (0x26)	Digital Port 0	RD,WR	0
39 (0x27)	Digital Port 1	RD,WR	0
40 (0x28)	Digital Port 2	RD,WR	0
41 (0x29)	Digital Port 3	RD,WR	0
42 (0x2A)	Motor A Speed	RD,WR	0
43 (0x2B)	Motor A Direction	RD,WR	0
44 (0x2C)	Motor B Speed	RD,WR	0
45 (0x2D)	Motor B Direction	RD,WR	0

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Control table locations 6-9 set the direction of the four digital I/O ports. 0 (the default) makes the port an input, and a 1 makes the port an output.

Control table location 10 switches between sign magnitude PWM and locked antiphase PWM. Many HBridge chips are set up to use sign magnitude (like the L293/L298). Some commercial products (like the Sabertooth line) are set up to use locked antiphase.

Putting a 0 in location 10 sets the PWM to sign magnitude, and thus uses the two direction pins (and the direction control table entries) as well as the two PWM pins. Putting a 1 in location 10 sets the PWM to locked antiphase, and ignores the direction pins and control table entries, using just the PWM pins.

For locked antiphase mode, the value 127 will stop the motor, 126-0 goes in reverse, and 128-255 goes forwards.

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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.

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