Continous Servo Write
Set direction and speed of continuous rotation servo motor
Simulink Support Package for Arduino Hardware / Common
The Continous Servo Write block sets the direction and speed of a continuous rotation servo motor depending on the input value sent to the block on the Arduino® hardware pin.
The characteristics of some motors cause them to continue rotating even when the block
0. You can experiment to find an offset value that stops the
With Arduino Mega 2560 hardware, you can use External mode to determine the offset while your model is running on the hardware. For more details, see Tune and Monitor Model Running on Hardware.
If you use the Continous Servo Write block along with the Serial Receive and Serial Transmit blocks in a Simulink® model, use longer sample times to avoid overruns.
Maximum Number of Servo Blocks Allowed Per Simulink Model
The number of Servo blocks, Standard Servo Read, Standard Servo Write, and Continous Servo Write, you can use in your Simulink model depends on the number of timers on your Arduino hardware board. Every timer on the Arduino board can support up to 12 Servo blocks.
For example, consider the Arduino Mega 2560/ADK board. The maximum number of servo
blocks that can be used per Simulink model is 48. If your Simulink model utilizes a total number of 48 Servo blocks and the board has 5 timers,
timer 5 supports the first set of 12 (1 to 12) Servo blocks. Similarly, timer 1 supports the
next set of 12 (13-24) Servo blocks, timer 3 supports the next set of 12 (25-36) Servo
blocks, and finally, timer
4 supports the last set of 12 (37-48) servo
The Servo blocks are grouped as follows:
Set 1: Servo blocks 1 to 12
Set 2: Servo blocks 13 to 24
Set 3: Servo blocks 25 to 36
Set 4: Servo blocks 37 to 48
Set 5: Servo blocks 49 to 60
This table shows how to assign timers to Servo blocks depending on the Arduino board you are using. It also provides the maximum number of Servo blocks that you can use per Simulink model.
|Arduino Board Type||Timer||Maximum Number of Servo Blocks Per Simulink Model|
|Uno, Nano 3.0||1||Set 1|
|Mega 2560/ADK||1||Set 2|
|Leonardo, Robot Control Board, Robot Motor Board, Micro||1||Set 1|
|MKR 1000, MKR Wifi 1010, MKR Zero||TC4||Set 1|
|Nano 33 IoT||TC4||Set 1|
Data — Input value that determines speed and direction of continuous rotation servo
positive integer in the range [
The value sent to the block at the input port determines the speed and direction of rotation of the continuous rotation servo motor interfaced with the Arduino hardware board. For example:
-90to the block produces the maximum rate of rotation in one direction.
90to the block produces the maximum rate of rotation in the opposite direction.
0to the block stops the servo motor.
Sending out-of-range values, such as
300, to the block has the same effect as sending the minimum or maximum input values, respectively.
The block input port inherits the data type of the upstream block, and internally
converts it to
uint8 with an offset of
Pin number — Continuous servo write pin number
2 (default) | scalar
Specify the Arduino hardware board pin number to which the continuous rotation servo motor input signal is connected.
Do not assign the same pin number to multiple blocks within a Simulink model.
For more information on how to assign pins or view the pins for the Continous Servo Write block, see Pin Mapping for Arduino Timer Dependent Blocks.
View Pin Map — Open pin mapping for Arduino hardware boards
Click this button to view the pin mapping table associated with the Arduino hardware board you select.
Introduced in R2012a
Standard Servo Read | Standard Servo Write | PWM | Install Support for Arduino Hardware | Pin Mapping for Arduino Timer Dependent Blocks | Conflicting Pin Configurations on Arduino Timer | Model Configuration Parameters for Simulink Support Package for Arduino Hardware