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https://github.com/jkb-git/ESP32Servo

Arduino-compatible servo library for the ESP32
https://github.com/jkb-git/ESP32Servo

Last synced: 16 days ago
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Arduino-compatible servo library for the ESP32

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README 

        
= Servo Library for ESP32 =



This library attempts to faithfully replicate the semantics of the

Arduino Servo library (see http://www.arduino.cc/en/Reference/Servo)

for the ESP32, with two (optional) additions. The two new functions

expose the ability of the ESP32 PWM timers to vary timer width.



== License ==



Copyright (c) 2017 John K. Bennett.  All right reserved.



This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 of the License, or (at your option) any later version.



This library is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

Lesser General Public License for more details.



You should have received a copy of the GNU Lesser General Public

License along with this library; if not, write to the Free Software

Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA



Library Description:

--------------------

    Servo - Class for manipulating servo motors connected to ESP32 pins.

    int attach(pin )  - Attaches the given GPIO pin to the next free channel

        (channels that have previously been detached are used first), 

        returns channel number or 0 if failure. All pin numbers are allowed,

        but only pins 2,4,12-19,21-23,25-27,32-33 are recommended.

    int attach(pin, min, max  ) - Attaches to a pin setting min and max 

        values in microseconds; enforced minimum min is 500, enforced max

        is 2500. Other semantics are the same as attach().

    void write () - Sets the servo angle in degrees; a value below 500 is

        treated as a value in degrees (0 to 180). These limit are enforced,

        i.e., values are constrained as follows:

            Value                                   Becomes

            -----                                   -------

            < 0                                        0

            0 - 180                                 value (treated as degrees)

            181 - 499                                 180

            500 - (min-1)                             min

            min-max (from attach or default)   value (treated as microseconds)

            (max+1) - 2500                            max

    

    void writeMicroseconds() - Sets the servo pulse width in microseconds.

        min and max are enforced (see above). 

    int read() - Gets the last written servo pulse width as an angle between 0 and 180. 

    int readMicroseconds()   - Gets the last written servo pulse width in microseconds.

    bool attached() - Returns true if this servo instance is attached to a pin. 

    void detach() - Stops an the attached servo, frees the attached pin, and frees

        its channel for reuse. 

    

    *** New ESP32-specific functions **

    setTimerWidth(value) - Sets the PWM timer width (must be 16-20) (ESP32 ONLY);

        as a side effect, the pulse width is recomputed.

    int readTimerWidth() - Gets the PWM timer width (ESP32 ONLY) 

 

Useful Defaults:

----------------

default min pulse width for attach(): 1000us

default max pulse width for attach(): 2000us

default timer width 16 (if timer width is not set)

default pulse width 1500us (servos are initialized with this value)

MINIMUM pulse with: 500us

MAXIMUM pulse with: 2500us

MAXIMUM number of servos: 16 (this is the number of PWM channels in the ESP32)