Added ServoPin() class to PwmPin.h

Controls a 50-Hz servo motor using ESP32 built-in LED PWM.  Allows custom range for microseconds and degrees.

src/extras/PwmPin.cpp

@@ -88,3 +88,44 @@ void PwmPin::HSVtoRGB(float h, float s, float v, float *r, float *g, float *b ){
       break;
   }
 }
+
+////////////////////////////
+
+ServoPin::ServoPin(uint8_t channel, uint8_t pin, double initDegrees, uint16_t minMicros, uint16_t maxMicros, double minDegrees, double maxDegrees){
+  this->channel=channel & 0x07;
+  this->pin=pin;
+  this->minMicros=minMicros;
+  this->maxMicros=maxMicros;
+  this->minDegrees=minDegrees;
+  microsPerDegree=(double)(maxMicros-minMicros)/(maxDegrees-minDegrees);
+
+  ledc_timer_config_t ledTimer;
+  ledTimer.timer_num=LEDC_TIMER_1;
+  ledTimer.speed_mode=LEDC_HIGH_SPEED_MODE;
+  ledTimer.duty_resolution=LEDC_TIMER_16_BIT;
+  ledTimer.freq_hz=50;
+  ledc_timer_config(&ledTimer);
+
+  ledChannel.gpio_num=pin;
+  ledChannel.speed_mode=LEDC_HIGH_SPEED_MODE;
+  ledChannel.channel=(ledc_channel_t)(this->channel);
+  ledChannel.intr_type=LEDC_INTR_DISABLE;
+  ledChannel.timer_sel=LEDC_TIMER_1;
+  ledChannel.hpoint=0;
+  ledChannel.duty*=micros2duty;  
+  set(initDegrees);
+}
+
+void ServoPin::set(double degrees){
+  ledChannel.duty=(degrees-minDegrees)*microsPerDegree+minMicros;
+  
+  if(ledChannel.duty<minMicros)
+    ledChannel.duty=minMicros;
+  else if(ledChannel.duty>maxMicros)
+    ledChannel.duty=maxMicros;
+
+  ledChannel.duty*=micros2duty;  
+  ledc_channel_config(&ledChannel);
+}
+
+const double ServoPin::micros2duty=65535.0/20000.0;

src/extras/PwmPin.h

@@ -24,3 +24,23 @@ class PwmPin {
     static void HSVtoRGB(float h, float s, float v, float *r, float *g, float *b );       // converts Hue/Saturation/Brightness to R/G/B
 
 };
+
+class ServoPin {
+  uint8_t channel;                                          // channel must be in range [0,7] (only HighSpeed Channels will be used)
+  uint8_t pin;
+  uint16_t minMicros;
+  uint16_t maxMicros;
+  double minDegrees;
+  double microsPerDegree;
+  ledc_channel_config_t ledChannel;
+
+  static const double micros2duty;
+
+  public:
+    ServoPin(uint8_t channel, uint8_t pin, double initDegrees, uint16_t minMicros, uint16_t maxMicros, double minDegrees, double maxDegrees);
+    ServoPin(uint8_t channel, uint8_t pin, double initDegrees=0) : ServoPin(channel,pin,initDegrees,1000,2000,-90,90) {};
+    
+    void set(double degrees);                               // sets the Servo to degrees, where degrees is bounded by [minDegrees,maxDegrees]  
+    int getPin(){return pin;}                               // returns the pin number
+
+};

src/extras/extras.ino

@@ -5,7 +5,10 @@
 #include "PwmPin.h"
 
 PwmPin yellow(0,16);
-PwmPin red(1,17);
+PwmPin red(0,17);
+
+//ServoPin servo(3,18,-90);
+ServoPin servo(3,18,0,500,2200,-90,90);
 
 void setup(){
  
@@ -20,6 +23,21 @@ void setup(){
 
 void loop(){
 
+  
+  double STEP=1;
+
+  for(int i=-100*STEP;i<=100*STEP;i++){
+    servo.set((double)i/STEP);
+    delay(10);
+  }
+
+  for(int i=100*STEP;i>=-100*STEP;i--){
+    servo.set((double)i/STEP);
+    delay(10);
+  }
+ 
+  return;
+
   for(int i=0;i<100;i++){
     red.set(22,i);
     delay(10);