88 lines
3.5 KiB
Markdown
88 lines
3.5 KiB
Markdown
|
# 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(): 544us
|
|||
|
|
|
|||
|
|
default max pulse width for attach(): 2400us
|
|||
|
|
|
|||
|
|
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)
|