6. Setting reference

This section lists all of the settings that the Tic supports. For each setting, this section contains several pieces of information:

• The Offset of each setting is the location where it is stored in the Tic’s EEPROM memory. You can use this offset with the “Read setting” and “Set setting” commands.
• The Type of each setting specifies how many bits the setting occupies, and says whether it is signed or unsigned (if applicable). All the multi-byte settings use little-endian format, meaning that the least-significant byte comes first.
• The Data entry for each setting specifies how the data for that setting is encoded in the Tic’s memory. Some of the settings lack this field because they are simply dimensionless integers, so their encoding is straightforward.
• The Default entry for each setting is the default value it has on a new Tic or a Tic that has been reset to its defaults.
• The Range entry for each setting is the allowed range of values for the setting, if applicable. Trying to use a value outside of this range could result in unexpected behavior.
• The Settings file entry for each setting is the name of the setting in a Tic settings file, if applicable. You can save and load Tic settings files from the “File” menu of the Tic Control Center, or by using the Tic Command-line Utility (ticcmd).
• The Settings file data entry for each setting is the specification of how that setting is encoded in a settings file. Some of the settings lack this field because the encoding is straightforward.
• The Tic Control Center entry for each setting is the location of that setting in the Tic Control Center software, if applicable.

List of settings

• Control mode
• Never sleep
• Disable safe start
• Ignore ERR line high
• Automatically clear driver errors
• Soft error response
• Soft error position
• Serial baud rate / serial baud rate generator
• Serial device number
• Serial alternative device number
• Serial enable alternative device number
• Serial 14-bit device number
• Command timeout
• Serial CRC for commands
• Serial CRC for responses
• Serial 7-bit responses
• Serial response delay
• VIN measurement calibration
• Enable input averaging
• Input hysteresis
• Input scaling degree
• Invert input direction
• Input minimum
• Input neutral minimum
• Input neutral maximum
• Input maximum
• Target minimum
• Target maximum
• Encoder prescaler
• Encoder postscaler
• Enable unbounded position control
• SCL pin configuration
• SDA pin configuration
• TX pin configuration
• RX pin configuration
• RC pin configuration
• Switch polarity map
• Kill switch map
• Limit switch forward map
• Limit switch reverse map
• Current limit
• Current limit during error
• Step mode
• Decay mode (non-HP)
• Decay mode (HP)
• AGC mode (T249 only)
• AGC bottom current limit (T249 only)
• AGC current boost steps (T249 only)
• AGC frequency limit (T249 only)
• Enable unrestricted current limits (36v4 only)
• Fixed off time (36v4 only)
• Current trip blanking time (36v4 only)
• Enable adaptive blanking time (36v4 only)
• Mixed decay transition time (36v4 only)
• Max speed
• Starting speed
• Max acceleration
• Max deceleration
• Invert motor direction
• Enable automatic homing
• Automatic homing forward
• Homing speed towards
• Homing speed away
• Not initialized

Control mode

Offset	0x01
Type	unsigned 8-bit
Data	0: Serial / I²C / USB 1: STEP/DIR 2: RC position 3: RC speed 4: Analog position 5: Analog speed 6: Encoder position 7: Encoder speed
Default	Serial / I²C / USB
Settings file	control_mode
Settings file data	serial step_dir rc_position rc_speed analog_position analog_speed encoder_position encoder_speed
Tic Control Center	Input and motor settings tab, Control mode

The control mode determines what inputs the Tic will use to control the stepper motor, and whether to use position control or speed control.

Never sleep

Offset	Bit 0 of byte 0x02
Type	boolean
Default	false
Settings file	never_sleep
Tic Control Center	Advanced settings tab, Miscellaneous box, Never sleep

By default, if the Tic is powered from a USB bus that is in suspend mode (e.g. the computer is sleeping) and VIN power is not present, it will go to sleep to reduce its current consumption and comply with the USB specification. If you enable the “Never sleep” option, the Tic will never go to sleep.

Disable safe start

Offset	Bit 0 of byte 0x03
Type	boolean
Default	false
Settings file	disable_safe_start
Tic Control Center	Advanced settings tab, Miscellaneous box, Disable safe start

This option disables the safe start feature, which is described in Section 5.4.

Ignore ERR line high

Offset	Bit 0 of byte 0x04
Type	boolean
Default	false
Settings file	ignore_err_line_high
Tic Control Center	Advanced settings tab, Miscellaneous box, Ignore ERR line high

This option disables the “ERR line high” error, which is described in Section 5.4.

Automatically clear driver errors

Offset	Bit 0 of byte 0x08
Type	boolean
Default	true
Settings file	auto_clear_driver_error
Tic Control Center	Advanced settings tab, Miscellaneous box, Automatically clear driver errors

When enabled, this option causes the Tic to periodically clear latched motor driver errors, as described in Section 5.4.

Soft error response

Offset	0x53
Type	unsigned 8-bit
Data	0: De-energize 1: Halt and hold 2: Decelerate to hold 3: Go to position
Default	Decelerate to hole
Settings file	soft_error_response
Settings file data	deenergize, halt_and_hold, decel_to_hold, or go_to_position
Tic Control Center	Advanced settings tab, Soft error response box

This setting sets the soft error response type, as described in Section 5.4.

Soft error position

Offset	0x54
Type	signed 32-bit
Data	a position in units of microsteps
Default	0
Range	-2,147,483,648 to 2,147,483,647
Settings file	soft_error_position
Tic Control Center	Advanced settings tab, Soft error response box, Go to position

If the “Soft error response” setting is set to “Go to position”, this setting determines what position the Tic will go to when a soft error happens. For more information, see Section 5.4.

Serial baud rate / serial baud rate generator

Offset	0x05
Type	unsigned 16-bit
Data	12000000 bps divided by desired serial baud rate
Default	9600 bps
Range	200 bps to 115385 bps
Settings file	serial_baud_rate
Settings file data	Desired serial baud rate in bits per second
Tic Control Center	Input and motor settings tab, Serial box, Baud rate

The serial baud rate is the speed that the Tic uses for serial communication on its RX and TX lines. The Tic software presents the baud rate as a whole number in units of bits per second (bps). The value that actually is stored in the Tic’s EEPROM memory is a 16-bit unsigned integer called the “Serial baud rate generator”, and it 12000000 bps divided by the desired baud rate, rounded to the nearest whole number.

Serial device number

Offset	0x07 and 0x69
Type	unsigned 14-bit
Default	14
Range	0 to 16383
Settings file	serial_device_number
Tic Control Center	Input and motor settings tab, Serial box, Device number

This number serves as the device number to use for Pololu Protocol serial communication and the 7-bit address to use for I²C communication.

This number is stored in two separate pieces in the settings memory: the lower 7 bits of the device number are stored in the lower 7 bits of the settings byte at offset 0x07. The upper 7 bits of the device number are stored in the lower 7 bits of the settings byte at offset 0x69.

This setting was originally a 7-bit setting stored at offset 0x07, but it was expanded to 14 bits in firmware version 1.06.

Serial alternative device number

Offset	0x6A and 0x6B
Type	unsigned 14-bit
Default	0
Range	0 to 16383
Settings file	serial_alt_device_number
Tic Control Center	Input and motor settings tab, Serial box, Alternative device number numeric input

This is an alternative device number that the Tic can use for the Pololu Protocol. If the alternative device number is enabled, the Tic will respond both to it and to regular device number.

This number is stored in two separate pieces in the settings memory: the lower 7 bits of are stored in the lower 7 bits of the settings byte at offset 0x6A. The upper 7 bits are stored in the lower 7 bits of the settings byte at offset 0x6B.

This setting was added in firmware version 1.06.

Serial enable alternative device number

Offset	Bit 7 of byte 0x6A
Type	boolean
Default	0
Settings file	serial_enable_alt_device_number
Tic Control Center	Input and motor settings tab, Serial box, Alternative device number checkbox

If this setting is set to true, the Tic will pay attention to Pololu Protocol serial commands that are addressed to the alternative device number.

This setting was added in firmware version 1.06.

Command timeout

Offset	0x09
Type	unsigned 16-bit
Data	timeout value in units of milliseconds, or 0 to disable the feature
Default	1000 ms
Range	0 ms to 60000 ms
Settings file	command_timeout
Tic Control Center	Input and motor settings tab, Serial box, Enable command timeout

The “Command timeout” setting is the time in milliseconds before the Tic considers it an error if it has not received certain commands. See the description of the “Command timeout” error in Section 5.4.

Serial 14-bit device number

Offset	Bit 3 of byte 0x0B
Type	boolean
Default	false
Settings file	serial_14bit_device_number
Tic Control Center	Input and motor settings tab, Serial box, Enable 14-bit device number

If this setting is enabled, the Tic will expect two device number bytes in serial commands using the Pololu Protocol, and the maximum device number changes from 127 to 16383. See Section 9 for details about the Pololu Protocol.

This setting was added in firmware version 1.06.

Serial CRC for commands

Offset	Bit 0 of byte 0x0B
Type	boolean
Default	false
Settings file	serial_crc_for_commands
Tic Control Center	Input and motor settings tab, Serial box, Enable CRC for commands

With this option enabled, the Tic requires a 7-bit CRC byte to be appended to every serial command, as described in Section 9.

This setting was previously named “Serial CRC enabled” and stored in the settings file as serial_crc_enabled.

Serial CRC for responses

Offset	Bit 1 of byte 0x0B
Type	boolean
Default	false
Settings file	serial_crc_for_responses
Tic Control Center	Input and motor settings tab, Serial box, Enable CRC for responses

With this option enabled, the Tic appends a 7-bit CRC byte to every response it sends (unless the response is longer than 14 bytes), as described in Section 9.

This setting was added in firmware version 1.06.

Serial 7-bit responses

Offset	Bit 2 of byte 0x0B
Type	boolean
Default	false
Settings file	serial_7bit_responses
Tic Control Center	Input and motor settings tab, Serial box, Enable 7-bit responses

With this option enabled, the Tic encodes its serial responses using bytes between 0 and 0x7F, as described in Section 9. This can be useful in setups where the serial response from one Tic will be seen by other Tic devices.

This setting was added in firmware version 1.06.

Serial response delay

Offset	0x5E
Type	unsigned 8-bit
Data	time in units of microseconds
Default	0
Range	0 to 255
Settings file	serial_response_delay
Tic Control Center	Input and motor settings, Serial box, Response delay

This setting specifies the minimum amount of time to wait, in microseconds, before processing an I²C byte or sending a serial response. This setting was added in firmware version 1.02.

VIN measurement calibration

Offset	0x14
Type	signed 16-bit
Default	0
Range	−500 to +500
Settings file	vin_calibration
Tic Control Center	Advanced settings tab, Miscellaneous box, VIN measurement calibration

This setting adjusts the scaling of the Tic’s VIN measurements. If the Tic’s VIN readings are lower than the actual VIN voltage, you can use a positive value to scale the readings up. If the readings are high, you can use a negative value to scale the readings down. On the Tic T500 and Tic T825, a value of 33 corresponds to a 4% change. On the Tic T834, a value of 9 corresponds to a 4% change. On the Tic T249 and Tic 36v4, a value of 21 corresponds to a 4% change.

Enable input averaging

Offset	Bit 0 of 0x2E
Type	boolean
Default	true
Settings file	input_averaging_enabled
Tic Control Center	Input and motor settings tab, Input conditioning box, Enable input averaging

This setting enables RC/analog input averaging as described in Section 5.2.

Input hysteresis

Offset	0x2F
Type	unsigned 16-bit
Default	0
Range	0 to 65535
Settings file	input_hysteresis
Tic Control Center	Input and motor settings tab, Input conditioning box, Input hysteresis

This setting specifies the amount of hysteresis to apply to RC/analog inputs, as described in Section 5.2.

Input scaling degree

Offset	0x20
Type	unsigned 8-bit
Data	0: linear 1: quadratic 2: cubic
Default	linear
Settings file	input_scaling_degree
Settings file data	linear, quadratic, or cubic
Tic Control Center	Input and motor settings tab, RC and analog scaling box, Scaling degree

By default, the scaling function used to convert RC and analog inputs into a speed or position is linear. If you set the scaling degree to quadratic or cubic, then the Tic uses a higher-degree polynomial function to scale its RC or analog inputs, which can give you finer control when the input is closer to its neutral position. For more information, see Section 5.2.

Invert input direction

Offset	0x21
Type	unsigned 8-bit
Data	0: false 1: true
Default	false
Settings file	input_invert
Settings file data	false or true
Tic Control Center	Input and motor settings tab, RC and analog scaling box, Invert input direction

By default, lower analog voltages and shorter RC pulse widths correspond to negative positions and speeds. When enabled, this setting flips that correspondence, as described in Section 5.2.

Input minimum

Offset	0x22
Type	unsigned 16-bit
Default	0
Range	0 to 4095
Settings file	input_min
Tic Control Center	Input and motor settings tab, RC and analog scaling box, Input column, Minimum

This is one of the RC/analog input scaling parameters described in Section 5.2.

Input neutral minimum

Offset	0x24
Type	unsigned 16-bit
Default	2015
Range	0 to 4095
Settings file	input_neutral_min
Tic Control Center	Input and motor settings tab, RC and analog scaling box, Input column, Neutral min

This is one of the RC/analog input scaling parameters described in Section 5.2.

Input neutral maximum

Offset	0x26
Type	unsigned 16-bit
Default	2080
Range	0 to 4095
Settings file	input_neutral_max
Tic Control Center	Input and motor settings tab, RC and analog scaling box, Input column, Neutral max

This is one of the RC/analog input scaling parameters described in Section 5.2.

Input maximum

Offset	0x28
Type	unsigned 16-bit
Default	4095
Range	0 to 4095
Settings file	input_max
Tic Control Center	Input and motor settings tab, RC and analog scaling box, Input column, Maximum

This is one of the RC/analog input scaling parameters described in Section 5.2.

Target minimum

Offset	0x2A
Type	signed 32-bit
Default	−200
Range	−2,147,483,647 to 0
Settings file	output_min
Tic Control Center	Input and motor settings tab, RC and analog scaling box, Target column, Minimum

This is one of the RC/analog input scaling parameters described in Section 5.2.

Target maximum

Offset	0x32
Type	signed 32-bit
Default	200
Range	0 to 2,147,483,647
Settings file	output_max
Tic Control Center	Input and motor settings tab, RC and analog scaling box, Target column, Maximum

This is one of the RC/analog input scaling parameters described in Section 5.2.

Encoder prescaler

Offset	0x58
Type	unsigned 32-bit
Default	1
Range	1 to 2,147,483,647
Settings file	encoder_prescaler
Tic Control Center	Input and motor settings tab, Encoder box, Prescaler

For encoder control modes, this determines the number of encoder counts per unit change of the stepper motor position or speed, as described in Section 5.3.

Encoder postscaler

Offset	0x37
Type	unsigned 32-bit
Default	1
Range	1 to 2,147,483,647
Settings file	encoder_postscaler
Tic Control Center	Input and motor settings tab, Encoder box, Postscaler

For encoder control modes, this determines the size of a unit change in the stepper motor position or speed, as described in Section 5.3.

Enable unbounded position control

Offset	0x5C
Type	unsigned 8-bit
Data	0: false 1: true
Default	false
Settings file	encoder_unlimited
Settings file data	false or true
Tic Control Center	Input and motor settings tab, Encoder box, Enable unbounded position control

This setting is described in Section 5.3.

SCL pin configuration

Offset	0x3B
Type	8-bit
Data	Bits 0–3: Pin function: 0: Default (see below) 1: User I/O 2: User input 3: Potentiometer power (drives high) 4: SCL (I²C clock line) 7: Kill switch 8: Limit switch forward 9: Limit switch reverse Bits 4–5: reserved, should be 0 Bit 6: Enable analog readings Bit 7: Enable internal pull-up
Default	0
Settings file	scl_config
Settings file data	Space-separated list including a subset of pin options (pullup, analog, and active_high) and one pin function: default, user_io, user_input, pot_power, serial (SCL), or kill_switch.
Tic Control Center	Advanced settings tab, Pin configuration box, SCL

This byte contains most of the configuration of the SCL pin, as described in Section 5.5.

If the pin function is set to “Default”, then the Tic will ignore all of the options set in this byte and just use default settings. The default settings for SCL depend on the control mode: in an analog control mode, SCL is configured as a potentiometer power pin, while in all other control modes, the SCL pin is used as the I²C clock line with its internal pull-up enabled.

SDA pin configuration

Offset	0x3C
Type	8-bit
Data	Bits 0–3: Pin function: 0: Default (see below) 1: User I/O 2: User input 4: SDA (I²C data line) 7: Kill switch 8: Limit switch forward 9: Limit switch reverse Bits 4–5: reserved, should be 0 Bit 6: Enable analog readings Bit 7: Enable internal pull-up
Default	0
Settings file	sda_config
Settings file data	Space-separated list including a subset of pin options (pullup, analog, and active_high) and one pin function: default, user_io, user_input, serial (SDA), or kill_switch.
Tic Control Center	Advanced settings tab, Pin configuration box, SDA

This byte contains most of the configuration of the SDA pin, as described in Section 5.5.

If the pin function is set to “Default”, then the Tic will ignore all of the options set in this byte and just use default settings. The default settings for SDA depend on the control mode: in an analog control mode, SDA is configured as a user input with analog readings enabled, while in all other control modes, SDA is used as the I²C data line with its internal pull-up enabled.

TX pin configuration

Offset	0x3D
Type	8-bit
Data	Bits 0–3: Pin function: 0: Default (see below) 1: User I/O 2: User input 4: TX (serial transmit line) 6: Encoder input 7: Kill switch 8: Limit switch forward 9: Limit switch reverse Bits 4–5: reserved, should be 0 Bit 6: Enable analog readings Bit 7: Ignored (TX is always pulled up)
Default	0
Settings file	tx_config
Settings file data	Space-separated list including a subset of pin options (analog and active_high) and one pin function: default, user_io, user_input, serial (TX), encoder, or kill_switch.
Tic Control Center	Advanced settings tab, Pin configuration box, TX

This byte contains most of the configuration of the TX pin, as described in Section 5.5.

If the pin function is set to “Default”, then the Tic will ignore all of the options set in this byte and just use default settings. The default settings for TX depend on the control mode: in an encoder control mode, TX is configured as an encoder input, while in all other control modes, TX is used as the serial transmit line.

RX pin configuration

Offset	0x3E
Type	8-bit
Data	Bits 0–3: Pin function: 0: Default (see below) 1: User I/O 2: User input 4: RX (serial receive line) 6: Encoder input 7: Kill switch 8: Limit switch forward 9: Limit switch reverse Bits 4–5: reserved, should be 0 Bit 6: Enable analog readings Bit 7: Ignored (RX is always pulled up)
Default	0
Settings file	rx_config
Settings file data	Space-separated list including a subset of pin options (analog and active_high) and one pin function: default, user_io, user_input, serial (RX), encoder, or kill_switch.
Tic Control Center	Advanced settings tab, Pin configuration box, RX

This byte contains most of the configuration of the RX pin, as described in Section 5.5.

If the pin function is set to “Default”, then the Tic will ignore all of the options set in this byte and just use default settings. The default settings for RX depend on the control mode: in an encoder control mode, RX is configured as an encoder input, while in all other control modes, RX is used as the serial receive line.

RC pin configuration

Offset	0x3F
Type	8-bit
Data	Bits 0–3: Pin function: 0: Default (see below) 2: User input 5: RC input 7: Kill switch 8: Limit switch forward 9: Limit switch reverse Bits 4–5: reserved, should be 0 Bit 6: Ignored (cannot do analog readings) Bit 7: Ignored (pin is always pulled down)
Default	0
Settings file	rc_config
Settings file data	Space-separated list including a subset of pin options (active_high or nothing) and one pin function: default, user_input, rc, or kill_switch.
Tic Control Center	Advanced settings tab, Pin configuration box, RC

This byte contains most of the configuration of the RC pin, as described in Section 5.5.

If the pin function is set to “Default”, then the Tic will use the RC pin as an RC pulse input and measure the durations of pulses received on the line.

Switch polarity map

Offset	0x36
Type	8-bit
Data	Bit 0: polarity of SCL pin if it is used as a switch Bit 1: polarity of SDA pin if it is used as a switch Bit 2: polarity of TX pin if it is used as a switch Bit 3: polarity of RX pin if it is used as a switch Bit 4: polarity of RC pin if it is used as a switch Bits 5–7: reserved, should be 0
Default	0
Settings file	Listed in scl_config, sda_config, tx_config, rx_config, rc_config
Settings file data	active_high or nothing
Tic Control Center	Advanced settings tab, Pin configuration, Active high checkboxes

For each pin configured as a switch, this setting allows you to choose whether that pin is active high or active low. If the pin’s switch polarity bit is 0, it is active low (a low voltage corresponds to an active switch). If the bit is 1, it is active high.

Kill switch map

Offset	0x5D
Type	8-bit
Data	Bit 0: 1 if SCL pin is used as a kill switch Bit 1: 1 if SDA pin is used a kill switch Bit 2: 1 if TX pin is used as a kill switch Bit 3: 1 if RX pin is used as a kill switch Bit 4: 1 if RC pin is used as a kill switch Bits 5–7: reserved, should be 0
Default	0

This byte contains redundant information to make the firmware implementation simpler. Each of the five input pins of the Tic has one bit in this byte. If the bit is 0, it means that the pin is not a kill switch. If the bit is 1, it means that the pin is a kill switch.

Limit switch forward map

Offset	0x5F
Type	8-bit
Data	Bit 0: 1 if SCL pin is used as a forward limit switch Bit 1: 1 if SDA pin is used a forward limit switch Bit 2: 1 if TX pin is used as a forward limit switch Bit 3: 1 if RX pin is used as a forward limit switch Bit 4: 1 if RC pin is used as a forward limit switch Bits 5–7: reserved, should be 0
Default	0

This byte contains redundant information to make the firmware implementation simpler.

Limit switch reverse map

Offset	0x60
Type	8-bit
Data	Bit 0: 1 if SCL pin is used as a reverse limit switch Bit 1: 1 if SDA pin is used a reverse limit switch Bit 2: 1 if TX pin is used as a reverse limit switch Bit 3: 1 if RX pin is used as a reverse limit switch Bit 4: 1 if RC pin is used as a reverse limit switch Bits 5–7: reserved, should be 0
Default	0

This byte contains redundant information to make the firmware implementation simpler.

Current limit

Offset	0x40
Type	unsigned 8-bit
Data	Tic T500: see current limit code table below Tic T834 and Tic T825: current limit, in units of 32 mA Tic T249: current limit, in units of 40 mA Tic 36v4: current limit, in units of 71.615 mA
Default	Tic T500: 174 mA Tic T834 and Tic T825: 192 mA Tic T249: 200 mA Tic 36v4: 215 mA
Range	Tic T500: 0 mA to 3093 mA Tic T834: 0 mA to 3456 mA Tic T825: 0 mA to 3968 mA Tic T249: 0 mA to 4480 mA Tic 36v4: 0 mA to 9095 mA
Settings file	current_limit
Settings file data	current limit, in units of mA
Tic Control Center	Input and motor settings, Motor box, Current limit

This setting determines how much current the Tic’s motor driver will attempt to generate in the stepper motor coils. For general information about the current limit, see Section 4.3.

Note that this setting just sets the default current limit, and it can be temporarily overridden using the “Set current limit” command.

The Tic T500 represents current limits using codes between 0 and 32. The table below shows the correspondence between these current limit codes and the nominal current limit.

Current limit code	Tic T500 current limit
0	0 mA
1	1 mA
2	174 mA
3	343 mA
4	495 mA
5	634 mA
6	762 mA
7	880 mA
8	990 mA
9	1092 mA
10	1189 mA
11	1281 mA
12	1368 mA
13	1452 mA
14	1532 mA
15	1611 mA
16	1687 mA
17	1762 mA
18	1835 mA
19	1909 mA
20	1982 mA
21	2056 mA
22	2131 mA
23	2207 mA
24	2285 mA
25	2366 mA
26	2451 mA
27	2540 mA
28	2634 mA
29	2734 mA
30	2843 mA
31	2962 mA
32	3093 mA

The Tic T834, Tic T825, and Tic T249 represent current limits using numbers between 0 and 124 that are linearly proportional to the current limit. However, due to hardware limitations, not all of these current limits are actually achievable. Disregarding the maximum allowed current limits documented above, the achievable current limits are as follows: 0 through 31, even numbers from 32 to 62, and multiples of four from 64 to 124. If you set a current limit that is not achievable, the Tic will generally accept it and store it in the “Current limit” variable, but it will actually have the same effect as the highest achievable current limit lower than it. For example, a current limit of 33 is the same as a current limit of 32, and a current limit of 66 is the same as a current limit of 64.

The Tic 36v4 represents current limits using numbers between 0 and 127 that are linearly proportional to the current limit. All numbers within this range are valid current limits.

Tic 36v4 warning: The Tic 36v4 has no meaningful over-temperature shut-off (while the gate driver IC has over-temperature protection, it is the external MOSFETs that will overheat first). An over-temperature condition can cause permanent damage to the motor driver. We strongly recommend you do not increase the current limit setting beyond 4000 mA (or lower in applications with reduced heat dissipation) unless you can first confirm that the temperature of the MOSFETs will stay under 140°C. By default, the Tic will prevent you from setting a current limit above 4000 mA, but you can override this using the Enable unrestricted current limits setting.

Current limit during error

Offset	0x31
Type	unsigned 8-bit
Data	current limit code as specified above for the normal current limit setting, or 0xFF to disable the feature
Default	0
Range	between 0 mA and the normal current limit setting, or disabled
Settings file	current_limit_during_error
Settings file data	current limit, in units of mA, or -1 to disable the feature
Tic Control Center	Advanced settings tab, Soft error response, Use different current limit during soft error

If enabled, this setting causes the Tic to use a different stepper motor current limit instead of the normal current limit if an error is happening and the driver is enabled. See Section 5.4.

Step mode

Offset	0x41
Type	unsigned 8-bit
Data	0: Full step 1: 1/2 step 2: 1/4 step 3: 1/8 step 4: 1/16 step 5: 1/32 step 6: 1/2 step 100% 7: 1/64 step 8: 1/128 step 9: 1/256 step
Default	Full step
Settings file	step_mode
Settings file data	1, 2, 2_100p, 4, 8, 16, 32, 64, 128, 256, full, or half
Tic Control Center	Input and motor settings tab, Motor box, Step mode

The step mode setting determines how many microsteps add up to one full step. More information about the step modes can be found in Section 4.3.

The different Tic models have different available step modes:

• The Tic T500 only supports full, 1/2, 1/4, and 1/8 step modes.
• The Tic T825 Tic T834, and Tic T249 support full, 1/2, 1/4, 1/8, 1/16, and 1/32 step modes.
  • The Tic T249 supports “Full step 100%” mode instead of normal full step mode, and it additionally supports “1/2 step 100%” mode. In these two “100%” modes, any non-zero coil current is 100% of the rated current instead of 70% (as in the normal full and 1/2 step modes). These modes are sometimes described as “non-circular”.
• The Tic 36v4 supports full, 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128, and 1/256 step modes.

Note that this setting just sets the default step mode, and it can be temporarily overridden using the “Set step mode” command.

Decay mode (non-HP)

Offset	0x42
Type	unsigned 8-bit
Data	Tic T500: 0: Automatic Tic T249: 0: ADMD Tic T825: 0: Mixed 1: Slow 2: Fast Tic T834: 0: Mixed 50% 1: Slow 2: Fast 3: Mixed 25% 4: Mixed 75%
Default	0
Settings file	decay_mode
Settings file data	mixed, slow, fast, mixed25, mixed50, or mixed75
Tic Control Center	Input and motor settings tab, Motor box, Decay mode

This setting does not apply to the Tic 36v4. For that Tic, see Decay mode (HP) instead.

More information about the Tic T500 automatic decay mode selection can be found in the MP6500 datasheet (1MB pdf) and Section 4.3.

More information about the Tic T249’s Advanced Dynamic Mixed Decay (ADMD) can be found in the TB67S249FTG datasheet (533k pdf) and Section 4.3.

More information about the Tic T825 decay modes can be found in the DRV8825 datasheet (1k redirect) and Section 4.3.

More information about the Tic T834 decay modes can be found in the DRV8834 datasheet (1k redirect) and Section 4.3.

Note that this setting just sets the default decay mode, and it can be temporarily overridden using the “Set decay mode” command.

Decay mode (HP)

Data	Slow Slow / mixed Fast Mixed Slow / auto mixed Auto mixed
Default	Auto mixed
Settings file	hp_decmod
Settings file data	slow, slow_mixed, fast, mixed, slow_auto_mixed, auto_mixed
Tic Control Center	Input and motor settings tab, Motor box, Decay mode

This setting only applies to the Tic 36v4. For other Tic boards, see Decay mode (non-HP).

More information about the Tic 36v4 decay modes can be found in the DRV8711 datasheet (1k redirect) and Section 4.3.

AGC mode

Offset	0x6C
Type	unsigned 8-bit
Data	0: Off 1: On 2: Active off
Default	Off
Settings file	agc_mode
Settings file data	off, on, or active_off
Tic Control Center	Input and motor settings tab, Motor box, AGC mode

This setting only applies to the Tic T249. It controls whether the Active Gain Control (AGC) feature is enabled or not. The three options are:

• Off: AGC is disabled.
• On: AGC is enabled.
• Active off: AGC is disabled, but if you are using full-step mode (i.e. not using microstepping), the driver inserts a period of time for each coil where the coil’s current is zero, just like it would do if AGC were enabled.

More information about these AGC modes can be found in the TB67S249FTG application note (1MB pdf).

Note that this setting just sets the default AGC mode, and it can be temporarily overridden using the “Set AGC option” command.

AGC bottom current limit

Offset	0x6D
Type	unsigned 8-bit
Data	0: 45% 1: 50% 2: 55% 3: 60% 4: 65% 5: 70% 6: 75% 7: 80%
Default	80%
Settings file	agc_bottom_current_limit
Settings file data	45, 50, 55, 60, 65, 70, 75, or 80
Tic Control Center	Input and motor settings tab, Motor box, AGC bottom current limit

This setting only applies to the Tic T249. It controls how much the Active Gain Control (AGC) can reduce the coil current when a light load on the motor is detected. With the default value of 80%, the AGC will only reduce the current limit down to 80% of the configured current limit. You can find more information about this setting in the TB67S249FTG datasheet (533k pdf).

Note that this setting just sets the default bottom current limit, and it can be temporarily overridden using the “Set AGC option” command.

AGC current boost steps

Offset	0x6E
Type	unsigned 8-bit
Data	0: 5 steps 1: 7 steps 2: 9 steps 3: 11 steps
Default	5 steps
Settings file	agc_current_boost_steps
Settings file data	5, 7, 9, or 11
Tic Control Center	Input and motor settings tab, Motor box, AGC current boost steps

This setting only applies to the Tic T249. It controls how long the Active Gain Control (AGC) takes to increase the current in the coils when a heavy load on the motor is detected. With the default value of 5 steps, the AGC will increase the current in 5 steps, which is the quickest option available. You can find more information about this setting in the TB67S249FTG datasheet (533k pdf).

Note that this setting just sets the default number of steps, and it can be temporarily overridden using the “Set AGC option” command.

AGC frequency limit

Offset	0x6F
Type	unsigned 8-bit
Data	0: Off 1: 225 Hz 2: 450 Hz 3: 675 Hz
Default	Off
Settings file	agc_frequency_limit
Settings file data	off, 225, 450, or 675
Tic Control Center	Input and motor settings, Motor box, AGC frequency limit

This setting only applies to the Tic T249. It controls the frequency limit feature provided by the TB67S249FTG driver, which can optionally prevent the the Active Gain Control (AGC) from lowering the coil current if the stepping frequency is too low. The default value of “Off” disables this feature. The other values specify a lower limit on the frequency of full steps.

For example, if this setting is 225 Hz, then the AGC will not activate unless the rate of full steps is at least 225 Hz. If you are using 1/4 microstepping, this corresponds to a microstep frequency of 900 Hz, which corresponds to a speed of approximately 9,000,000.

You can find more information about this setting in the TB67S249FTG datasheet (533k pdf).

Note that this setting just sets the default AGC frequency limit, and it can be temporarily overridden using the “Set AGC option” command.

Enable unrestricted current limits

Offset	Bit 0 of 0x6C
Type	boolean
Default	false
Settings file	hp_enable_unrestricted_current_limits
Tic Control Center	Input and motor settings tab, Motor box, Enable adaptive blanking time

This setting only applies to the Tic 36v4.

By default, the Tic 36v4 caps its current limit at 3939 mA (which is encoded as 55). Any attempt to set a current limit above that, whether from a setting or a command, results in 3939 mA. If this setting is enabled, that limit is disabled, and currents can go all the way up to 9095 mA (encoded as 127). Please read the warning below if you are considering enabling this setting.

Tic 36v4 warning: The Tic 36v4 has no meaningful over-temperature shut-off (while the gate driver IC has over-temperature protection, it is the external MOSFETs that will overheat first). An over-temperature condition can cause permanent damage to the motor driver. We strongly recommend you do not increase the current limit setting beyond 4000 mA (or lower in applications with reduced heat dissipation) unless you can first confirm that the temperature of the MOSFETs will stay under 140°C.

Fixed off time

Default	25.5 μs
Range	0.5 μs to 128.0 μs, 0.5 μs increments
Settings file	hp_toff
Tic Control Center	Input and motor settings tab, Motor box, Fixed off time

This setting only applies to the Tic 36v4. The driver uses PWM current regulation to limit the motor coil current; at the start of each PWM cycle, the H-bridge is enabled and current starts increasing through the motor coil. Once the current reaches the limit (chopping threshold), the H-bridge is disabled and the current is allowed to decay for a fixed period, which is determined by this parameter. Decreasing the fixed off time increases the PWM frequency, which can reduce current ripple, but it also increases heat from switching losses. If the fixed off time is too short or too long for the selected decay mode, current waveform distortion can occur.

You can find more information about this setting in the DRV8711 datasheet (1k redirect). The DRV8711 Decay Mode Setting Optimization Guide (1k redirect) shows how changing this parameter can help improve current waveforms.

Current trip blanking time

Default	1.00 μs
Range	1.00 μs to 5.10 μs, 0.02 μs increments
Settings file	hp_tblank
Tic Control Center	Input and motor settings tab, Motor box, Current trip blanking time

This setting only applies to the Tic 36v4. It determines the minimum on time for each PWM cycle. You can find more information about this setting in the DRV8711 datasheet (1k redirect).

Enable adaptive blanking time

Type	boolean
Default	true
Settings file	hp_abt
Tic Control Center	Input and motor settings tab, Motor box, Enable adaptive blanking time

This setting only applies to the Tic 36v4. If enabled, it causes the driver to cut the blanking time in half for low current steps, which can help improve current control accuracy. You can find more information about this setting in the DRV8711 datasheet (1k redirect).

Mixed decay transition time

Default	8.0 μs
Range	0.0 μs to 127.5 μs, 0.5 μs increments
Settings file	hp_tdecay
Tic Control Center	Input and motor settings tab, Motor box, Mixed decay transition time

This setting only applies to the Tic 36v4. When the driver is configured to use mixed decay, it begins by using fast decay but transitions to slow decay after a fixed period, which is determined by this parameter. You can find more information about this setting in the DRV8711 datasheet (1k redirect) and the DRV8711 Decay Mode Setting Optimization Guide (1k redirect).

Max speed

Offset	0x47
Type	unsigned 32-bit
Data	speed in units of pulses per 10,000 seconds
Default	2,000,000 (200 pulses/s)
Range	0 to 500,000,000 (50,000 pulses/s)
Settings file	max_speed
Tic Control Center	Input and motor settings, Motor box, Max speed

The “Max speed” setting is the upper limit on how fast the Tic will try to drive the stepper motor. For more information, see Section 5.1.

Note that this setting just sets the default value for the “Max speed” motion parameter, and it can be temporarily overridden using the “Set max speed” command.

Starting speed

Offset	0x43
Type	unsigned 32-bit
Data	speed in units of pulses per 10,000 seconds
Default	0
Range	0 to 500,000,000 (50,000 pulses/s)
Settings file	starting_speed
Tic Control Center	Input and motor settings, Motor box, Starting speed

The “Starting speed” is the maximum speed at which instant acceleration and deceleration are allowed. For more information, see Section 5.1.

Note that this setting just sets the default value for the “Starting speed” motion parameter, and it can be temporarily overridden using the “Set starting speed” command.

Max acceleration

Offset	0x4F
Type	unsigned 32-bit
Data	acceleration in units of pulses per second per 100 seconds
Default	40,000
Range	100 to 2,147,483,647
Settings file	max_accel
Tic Control Center	Input and motor settings tab, Motor box, Max acceleration

The “Max acceleration” setting specifies how rapidly the speed is allowed to increase. For more information, see Section 5.1.

Note that this setting just sets the default value for the “Max acceleration” motion parameter, and it can be temporarily overridden using the “Set max acceleration” command.

Max deceleration

Offset	0x4B
Type	unsigned 32-bit
Data	deceleration in units of pulses per second per 100 seconds, or 0 to make it the same as the max acceleration
Default	0
Range	100 to 2,147,483,647
Settings file	max_decel
Tic Control Center	Input and motor settings tab, Motor box, Max deceleration

The “Max deceleration” setting specifies how rapidly the speed is allowed to decrease. For more information, see Section 5.1.

Note that this setting just sets the default value for the “Max deceleration” motion parameter, and it can be temporarily overridden using the “Set max deceleration” command. Also, even if this setting is 0 (which corresponds to checking the “Use max acceleration limit for deceleration” box in the Tic Control Center), the “Set max acceleration” command will only change the max acceleration without changing the max deceleration.

Invert motor direction

Offset	Bit 0 of 0x1B
Type	boolean
Default	false
Settings file	invert_motor_direction
Tic Control Center	Input and motor settings tab, Motor box, Invert motor direction

By default, an increasing position or a positive speed corresponds to taking steps forward through the motor driver’s current indexer table, so the amount of current flowing from B1 to B2 lags behind the amount of current flowing from A1 to A2. This setting flips that correspondence if it is enabled, making the motor turn in the opposite direction. See Section 5.1.

Enable automatic homing

Offset	Bit 1 of byte 0x02
Type	boolean
Default	false
Settings file	auto_homing
Tic Control Center	Advanced settings tab, Homing box, Enable automatic homing

If true, the Tic will start the homing procedure automatically whenever the “Position uncertain” flag is set, the “Operation state” is “Normal”, and the “Input state” variable (which is set either by the control mode or by serial commands) is “Target position”. This setting is mainly intended for use with “RC Position”, “Analog position”, and “Encoder position” control modes. See Section 5.6 for more information about homing.

Automatic homing forward

Offset	Bit 2 of byte 0x02
Type	boolean
Default	false
Settings file	auto_homing_forward
Tic Control Center	Advanced settings tab, Homing box, Automatic homing direction

If true, the Tic’s automatic homing feature will perform homing in the forward direction. If false, the automatic homing feature will perform homing in the reverse direction.

Homing speed towards

Offset	0x61
Type	unsigned 32-bit
Data	speed in units of pulses per 10,000 seconds
Default	1000000 (100 pulses/s)
Range	0 to 500,000,000 (50,000 pulses/s)
Settings file	homing_speed_towards
Tic Control Center	Advanced settings tab, Homing box, Homing speed towards

This is the speed that the Tic uses during the homing procedure when it is travelling towards the limit switch. See Section 5.6.

Homing speed away

Offset	0x65
Type	unsigned 32-bit
Data	speed in units of pulses per 10,000 seconds
Default	1000000 (100 pulses/s)
Range	0 to 500,000,000 (50,000 pulses/s)
Settings file	homing_speed_away
Tic Control Center	Advanced settings tab, Homing box, Homing speed away

This is the speed that the Tic uses briefly during the homing procedure when it is travelling away from the limit switch to deactivate it. See Section 5.6.

Not initialized

Offset	0x00
Type	unsigned 8-bit
Data	0: false non-zero: true
Default	false

This special setting keeps track of whether the rest of the settings have been initialized or not. Normally it is zero, which means false. If you set it to a non-zero value, then the Tic will reset all of the settings to their default values the next time the Tic is reset or reinitialized. This is how the “Restore default settings” command in the Tic Control Center and the --restore-defaults option in the command-line utility are implemented.