FEETECH SCSCL Servo – Memory Table Analysis

SCSCL Servo – Memory Table Analysis

Magnetic Encoder SCSCL Servo

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1. Servo Communication Protocol

The servo uses the FT-SCS custom protocol. The factory default baud rate is 1 Mbps or 500 kbps, using TTL single-wire bus communication, with 8 data bits, no parity, and 1 stop bit.

The baud rate is configurable from 38,400 to 1 Mbps (or 500 kbps). The default communication address (station ID) is 1.

2. Servo Memory Table Definition

If the function address uses two bytes of data, the low byte is stored at the lower address, and the high byte is stored at the higher address.

2.1 Version Information

Address (DEC)	Address (HEX)	Function Name	Number of Bytes	Initial Value	Access	Value Range	Unit	Description
0	0x00	Firmware Major Version Number	1	–	RO
1	0x01	Firmware Minor Version Number	1	–	RO
2	0x02	END	1	1	RO			1 indicates big-endian storage structure
3	0x03	Servo Major Version Number	1	–	RO
4	0x04	Servo Minor Version Number	1	–	RO

2.2 EPROM Configuration

Address (DEC)	Address (HEX)	Function Name	Number of Bytes	Initial Value	Access	Value Range	Unit	Description
5	0x05	Servo ID	1	1	RW	0 ~ 253	No.	Unique master ID on the bus
6	0x06	Baud Rate	1	0	RW	0 ~ 7		0–7 correspond to: 1000000 (0), 500000 (1), 250000 (2), 128000 (3), 115200 (4), 76800 (5), 57600 (6), 38400 (7)
7	0x07	Undefined	1	–	RW	–
8	0x08	Response Status Level	1	1	RW	0 ~ 1		0: No response for instructions except READ and PING; 1: Respond to all instructions
9	0x09	Minimum Angle Limit	2	20	RW	0 ~ 1023	Step	Minimum operating angle limit; must be less than maximum angle limit; when minimum = maximum = 0, motor mode is enabled
11	0x0B	Maximum Angle Limit	2	1003	RW	1 ~ 1023	Step	Maximum operating angle limit; must be greater than minimum angle limit; when minimum = maximum = 0, motor mode is enabled
13	0x0D	Maximum Temperature Limit	1	70	RW	0 ~ 100	°C
14	0x0E	Maximum Input Voltage	1	–	RW	0 ~ 254	0.1 V	Maximum input voltage = minimum input voltage = 0 disables voltage feedback
15	0x0F	Minimum Input Voltage	1	40	RW	0 ~ 254	0.1 V	Maximum input voltage = minimum input voltage = 0 disables voltage feedback
16	0x10	Maximum Torque	2	1000	RW	0 ~ 1000	0.1 %	Assigned to address 48 (Torque Limit) at power-on
18	0x12	Phase	1	–	RW	0 ~ 254		Special function byte, do not modify unless required
19	0x13	Unload Condition	1	–	RW	0 ~ 254		Bit=1 enables corresponding protection; Bit=0 disables
20	0x14	LED Alarm Condition	1	–	RW	0 ~ 254		Bit=1 enables alarm flashing; Bit=0 disables
21	0x15	Position Loop Proportional Gain (Kp)	1	–	RW	0 ~ 254		Controls motor proportional gain
22	0x16	Position Loop Derivative Gain (Kd)	1	–	RW	0 ~ 254		Controls motor derivative gain
23	0x17	Undefined	1	–	RW	–	–
24	0x18	Minimum Starting Torque	1	–	RW	0 ~ 254	0.1 %	Sets minimum startup torque
25	0x19	Undefined	1	–	RW	–	–
26	0x1A	Positive Dead Zone	1	1	RW	0 ~ 16	Step	Minimum unit is one minimum resolvable angle
27	0x1B	Negative Dead Zone	1	1	RW	0 ~ 16	Step	Minimum unit is one minimum resolvable angle
28 ~ 36	0x1C ~ 0x24	Undefined	1	–	RW	–	–
37	0x25	Holding Torque	1	20	RW	0 ~ 254	1 %	Output torque after entering overload protection (e.g., 20 = 20%)
38	0x26	Protection Time	1	200	RW	0 ~ 254	10 ms	Time duration when overload condition is maintained (e.g., 200 = 2 s, max 2.5 s)
39	0x24	Overload Torque Threshold	1	80	RW	0 ~ 254	1 %	Threshold that triggers overload protection timing (e.g., 80 = 80% max torque)

2.3 SRAM Control

Address (DEC)	Address (HEX)	Function Name	Number of Bytes	Initial Value	Access	Value Range	Unit	Description
40	0x28	Torque Switch	1	0	RW	0 ~ 2		0: Disable torque / free state; 1: Enable torque; 2: Damping mode
41	0x29	Undefined	1	–	RW	–	–
42	0x2A	Target Position	2	0	RW	0 ~ 1023	Step	Each step corresponds to the minimum resolvable angle; absolute position control mode, maximum corresponds to the maximum valid angle
44	0x2C	Operating Time	2	0	RW	0 ~ 9999 / -1000 ~ 1000	1 ms / 0.1 %	Motion time from current position to target position; when operating speed is 0, this parameter takes effect; in motor mode, it sets PWM duty cycle output; Bit10 is direction bit
46	0x2E	Operating Speed	2	Default factory max speed	RW	0 ~ 1000	Step/s	Number of steps per second
48	0x30	Lock Flag	1	1	RW	0 ~ 1		0: Disable write lock (EPROM values saved after power-off); 1: Enable write lock (EPROM values not saved after power-off)
49 ~ 56	0x32 ~ 0x36	Undefined	1	–	RW	–	–

2.4 SRAM Feedback

Address (DEC)	Address (HEX)	Function Name	Number of Bytes	Initial Value	Access	Value Range	Unit	Description
56	0x38	Present Position	2	–	R	–	Step	Feedback of current position in steps; each step corresponds to the minimum angle resolution; in absolute position mode, maximum value corresponds to maximum valid angle
58	0x3A	Present Speed	2	–	R	–	Step/s	Feedback of current motor speed; number of steps per second
60	0x3C	Present Load	2	–	R	–	0.1 %	PWM duty cycle driving the motor; Bit10 is direction bit
62	0x3E	Present Voltage	1	–	R	–	0.1 V	Current operating voltage
63	0x3F	Present Temperature	1	–	R	–	°C	Internal temperature of the servo
64	0x40	Async Write Flag	1	0	R	–	–	Flag used during asynchronous write operations
65	0x41	Servo Status	1	0	R	–	–	Bit=1 indicates corresponding error
66	0x42	Moving Flag	1	0	R	–	–	1: moving; 0: stopped at target or no target update

2.5 Factory Parameters

Address (DEC)	Address (HEX)	Function Name	Number of Bytes	Initial Value	Access	Value Range	Unit	Description
78	0x4E	Maximum PWM Mode Step	1	20	R	–	–
79	0x50	Motion Speed Threshold ×50	1	1	R	–	–
80	0x51	DTs (ms)	1	20	R	–	–
81	0x52	Minimum Speed Limit ×50	1	1	R	–	–
82	0x53	Maximum Speed Limit ×50	1	–	R	–	–
83	0x54	Acceleration	1	20	R	–	–

3. Special Byte Description

3.1 Servo Phase

Bit number / bit weight: description

BIT0 (1): driver direction phase; (0) forward, (1) reverse
BIT1 (2): ----
BIT2 (4): ----
BIT3 (8): speed mode; (0) speed = 0 means stop, (1) speed = 0 means maximum speed
BIT4 (16): ----
BIT5 (32): PWM phase; (0) in-phase, (1) inverted phase
BIT6 (64): voltage mode; (0) 1.5K low-voltage sampling, (1) 1K high-voltage sampling
BIT7 (128): ----

💡

Note:If multiple bits are set simultaneously, the servo phase value equals the sum of all bit values.

3.2 Servo Status

Servo status: 0 indicates normal, 1 indicates abnormal

Bit number / bit weight: description

BIT0 (1): voltage status
BIT1 (2): ----
BIT2 (4): temperature status
BIT3 (8): ----
BIT4 (16): ----
BIT5 (32): load status
BIT6 (64): ----
BIT7 (128): ----

💡

Note:If multiple statuses occur simultaneously, the servo status value equals the sum of all bit values.

For example:voltage over/under-voltage and servo overheat, then the servo status value is 4 + 1 = 5.

3.3 Unload Condition

Unload condition: 0 indicates off, 1 indicates on

Bit number / bit weight: description

BIT0 (1): voltage protection
BIT1 (2): ----
BIT2 (4): overheat protection
BIT3 (8): ----
BIT4 (16): ----
BIT5 (32): load overload
BIT6 (64): ----
BIT7 (128): ----

💡

Note:If multiple bits are set, the unload condition value equals the sum of all bit values.

For example:voltage protection and overheat protection enabled at the same time, then the unload condition value is 4 + 1 = 5.

3.4 LED Alarm Condition

LED alarm condition: 0 indicates off, 1 indicates on

Bit number / bit weight: description

BIT0 (1): voltage alarm
BIT1 (2): ----
BIT2 (4): overheat alarm
BIT3 (8): ----
BIT4 (16): ----
BIT5 (32): load overload alarm
BIT6 (64): ----
BIT7 (128): ----

💡

Note: If multiple bits are set simultaneously, the LED alarm condition value equals the sum of all bit values.

For example: voltage alarm and overheat alarm enabled at the same time, then the alarm condition value is 4 + 1 = 5.

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On this page

SCSCL Servo – Memory Table Analysis
1. Servo Communication Protocol
2. Servo Memory Table Definition
2.1 Version Information
2.2 EPROM Configuration
2.3 SRAM Control
2.4 SRAM Feedback
2.5 Factory Parameters
3. Special Byte Description
3.1 Servo Phase
3.2 Servo Status
3.3 Unload Condition
3.4 LED Alarm Condition