CAN2.0A to FTSCS1.0 Protocol¶

This page is a transcription of the official《CAN2.0A转FTSCS1.0 协议》(CAN2.0A to FTSCS1.0 Protocol) document. FTSCS1.0 is the FT-SCS custom protocol (instruction frame and status frame structure) shared by all families in Bus Protocol; see FT-SCS Protocol. For the memory tables of each family, see Memory Table Parameters.

1. Protocol overview¶

This protocol is based on the CAN2.0A standard data frame: custom communication instructions are converted into the FTSCS1.0 custom protocol, so that all FEETECH custom-protocol bus servos can work together with CAN bus devices.

Communication uses CAN2.0A standard data frames. The factory default CAN baud rate is 1M, configurable in the range 100K~1M. The factory default CAN station number is 1; the CAN baud rate and the station address can both be set through CAN instructions. Since the FTSCS1.0 protocol is based on 485/TTL, the CAN converter must follow a strict question-answer communication rule, otherwise data conflicts may occur on the 485/TTL bus.

This conversion protocol must be used together with a specific FEETECH conversion module (such as the CAN2.0A-to-TTL single-bus module) to achieve the communication conversion function.

2. CAN2.0A frame format¶

CAN-ID	DLC	Data1 Data2 ... Data n
11-bit CAN-ID	Data length, range 0~8	1 byte per data field, n<=8

CAN-ID structure:

CAN-ID	BIT10 ... BIT6	BIT5 ... BIT0
	CAN instruction code	CAN station address

BIT5 ~ BIT0: CAN station number, range 0~63, where 0 is the broadcast address and 1~63 are unicast addresses
BIT10 ~ BIT6: CAN instruction code, indicating the function of the CAN message to be sent

CAN instruction codes:

Instruction code	Function	CAN-ID	Description
0x01	Memory table read instruction	0x080+CAN station number
0x02	Memory table write instruction	0x100+CAN station number
0x03	Position control instruction	0x180+CAN station number
0x04	Synchronous read instruction	0x200+CAN station number
0x05	Asynchronous control instruction	0x280+CAN station number
0x06	Asynchronous action instruction	0x300+CAN station number
0x07	Synchronous control instruction	0x380+CAN station number
0x08	Synchronous action instruction	0x400+CAN station number
0x09	Servo reply instruction	0x480+CAN station number	Used to carry the servo reply data
0x0A	CAN configuration instruction	0x500+CAN station number
0x0B	Servo calibration instruction	0x580+CAN station number

2.1 Memory table read instruction (0x01)¶

The memory table read instruction reads the servo memory table; at most 6 bytes can be read per instruction.

	CAN-ID	DLC	Data
Send	0x080+CAN station number	3	Servo ID (1 byte), memory table address (1 byte), memory table length N (1 byte, N<=6)
Reply	0x480+CAN station number	N+2	Servo ID (1 byte), servo status (1 byte), memory table data 1 (1 byte) ... memory table data N (1 byte)

2.2 Memory table write instruction (0x02)¶

The memory table write instruction writes data to the servo memory table; at most 6 bytes can be written per instruction.

	CAN-ID	DLC	Data
Send	0x100+CAN station number	N+2	Servo ID (1 byte), memory table address (1 byte), memory table data 1 (1 byte) ... memory table data N (1 byte, N<=6)
Reply	0x480+CAN station number	2	Servo ID (1 byte), servo status (1 byte)

2.3 Position control instruction (0x03)¶

The position control instruction controls the servo position. The input instruction includes: servo ID (1 byte), position (2 bytes), acceleration (1 byte), speed (2 bytes) and running current (2 bytes).

	CAN-ID	DLC	Data
Send	0x180+CAN station number	8	Servo ID (1 byte), target position (2 bytes), running acceleration (1 byte), running speed (2 bytes), running current (2 bytes)
Reply	0x480+CAN station number	2	Servo ID (1 byte), servo status (1 byte)

2.4 Synchronous read instruction (0x04)¶

The synchronous read instruction can read the memory table data of up to 6 servos at the same time.

	CAN-ID	DLC	Data
Send	0x200+CAN station number	n+2	Memory table address (1 byte), memory table length N (1 byte, N<=6), servo ID1 (1 byte) ... servo IDn (1 byte, n<=6)
Reply	0x480+CAN station number	N+2	Servo ID (1 byte), servo status (1 byte), memory table data 1 (1 byte) ... memory table data N (1 byte)

2.5 Asynchronous control instruction (0x05)¶

The asynchronous control instruction controls the servo position asynchronously. The input instruction includes: servo ID (1 byte), the input instruction includes position (2 bytes), acceleration (1 byte), speed (2 bytes) and running current (2 bytes).

	CAN-ID	DLC	Data
Send	0x280+CAN station number	8	Servo ID (1 byte), target position (2 bytes), running acceleration (1 byte), running speed (2 bytes), running current (2 bytes)
Reply	0x480+CAN station number	2	Servo ID (1 byte), servo status (1 byte)

2.6 Asynchronous action instruction (0x06)¶

The asynchronous action instruction executes the buffered asynchronous control instructions.

	CAN-ID	DLC	Data
Send	0x300+CAN station number	0	None

2.7 Synchronous control instruction (0x07)¶

The synchronous control instruction controls the servo position synchronously. The input instruction includes: servo ID (1 byte), the input instruction includes position (2 bytes), acceleration (1 byte), speed (2 bytes) and running current (2 bytes). The input instruction is first buffered in the CAN converter; after the synchronous action instruction is received, it is converted into the servo synchronous control instruction and output.

	CAN-ID	DLC	Data
Send	0x380+CAN station number	8	Servo ID (1 byte), target position (2 bytes), running acceleration (1 byte), running speed (2 bytes), running current (2 bytes)

2.8 Synchronous action instruction (0x08)¶

After the CAN converter receives the synchronous action, it converts the buffered synchronous control instructions into the servo synchronous control instruction and outputs it.

Action instruction:

	CAN-ID	DLC	Data
Send	0x400+CAN station number	0	None

Clear instruction:

	CAN-ID	DLC	Data
Send	0x400+CAN station number	1	0

Query instruction:

	CAN-ID	DLC	Data
Send	0x400+CAN station number	1	1
Reply	0x400+CAN station number	1	Number of buffered instructions (1 byte)

2.9 CAN configuration instruction (0x0A)¶

CAN configuration instruction:

	CAN-ID	DLC	Data
Send	0x500+CAN station number	3	CAN baud rate (1 byte), CAN station number (1 byte), servo baud rate (1 byte)
Reply	0x500+CAN station number	8	Baud rate (1 byte), CAN station number (1 byte), servo baud rate (1 byte), reserved (1 byte), firmware version (1 byte), firmware release year (1 byte), firmware distribution month (1 byte), firmware release day (1 byte)

CAN station number: 1~63
Servo baud rate: 0~3, 0 means 1M, 1 means 500k, 2 means 250k, 3 means 115200
CAN baud rate: 0~3, 0 means 1M, 1 means 500k, 2 means 250k, 3 means 100k

Return CAN configuration information:

	CAN-ID	DLC	Data
Send	0x500+CAN station number	0	None
Reply	0x500+CAN station number	8	Baud rate (1 byte), CAN station number (1 byte), servo baud rate (1 byte), reserved (1 byte), firmware version (1 byte), firmware release year (1 byte), firmware distribution month (1 byte), firmware release day (1 byte)

Note: configuration changes take effect after a restart

2.10 Servo calibration instruction (0x0B)¶

Recalibrate the current position to the set value:

	CAN-ID	DLC	Data
Send	0x580+CAN station number	3	Servo ID (1 byte), calibration position (2 bytes)
Reply	0x480+CAN station number	2	Servo ID (1 byte), servo status (1 byte)

Calibrate the current position to the midpoint:

	CAN-ID	DLC	Data
Send	0x580+CAN station number	1	Servo ID (1 byte)
Reply	0x480+CAN station number	2	Servo ID (1 byte), servo status (1 byte)