Adds a preliminary support for zephyr boards

.gitignore

@@ -0,0 +1 @@
+.vscode/settings.json

src/Servo.h

@@ -79,8 +79,10 @@
 #include "xmc/ServoTimers.h"
 #elif defined(ARDUINO_ARCH_ESP32)
 #include "esp32/ServoTimers.h"
+#elif defined(ARDUINO_ARCH_ZEPHYR)
+#include "zephyr/ServoTimers.h"
 #else
-#error "This library only supports boards with an AVR, SAM, SAMD, NRF52, STM32F4, Renesas, XMC or ESP32 processor."
+#error "This library only supports boards with an AVR, SAM, SAMD, NRF52, STM32F4, Renesas, XMC, ESP32 or Zephyr core."
 #endif
 
 #define Servo_VERSION           2     // software version of this library

src/zephyr/Servo.cpp

@@ -0,0 +1,191 @@
+#if defined(ARDUINO_ARCH_ZEPHYR)
+
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/gpio.h>
+#include <zephyr/device.h>
+#include <zephyr/drivers/counter.h>
+
+#include <Arduino.h>
+#include <Servo.h>
+
+
+typedef struct {
+    uint8_t pin;
+    uint32_t position_tick;
+    uint32_t timer_index;
+    uint32_t min;
+    uint32_t max;
+} servoTimer_t;
+
+class ServoTimerHandler{
+
+  inline static uint32_t timer_servo;
+  inline static uint32_t servo_timing_period;
+  bool timer_is_started;
+
+  inline static servoTimer_t * servos[MAX_ZEPHYR_SERVOS] = {nullptr};
+  uint8_t servoCount;
+
+  public:
+    ServoTimerHandler(){
+      timer_is_started = false;
+      timer_servo = 0;
+      servoCount = 0;
+    }
+
+    int initTimer(){
+      if (!timer_is_started){
+        const struct device *const counter_dev = DEVICE_DT_GET(TIMER);
+        counter_start(counter_dev);
+        struct counter_top_cfg top_cfg;
+        top_cfg.ticks = counter_us_to_ticks(counter_dev, servo_timer_base_us_tick);
+        top_cfg.callback = this->servo_timer_update; 
+        top_cfg.user_data = &top_cfg;
+        top_cfg.flags = 0;
+
+        int err = counter_set_top_value(counter_dev, &top_cfg);
+        if (err){
+          return 0;
+        }
+        else{
+          timer_is_started = true;
+          return 1;
+        }
+      }
+      return -1;
+    }
+
+    static void servo_timer_update(const struct device *counter_dev, void *user_data){
+      for (uint8_t i = 0; i < MAX_ZEPHYR_SERVOS; i++){
+        if (servos[i]!=nullptr){
+          if (timer_servo>servos[i]->position_tick){
+            digitalWrite(servos[i]->pin, LOW);
+          }
+          else{
+            digitalWrite(servos[i]->pin, HIGH);
+          }
+        }
+      }
+      if (timer_servo>servo_timer_end_tick){
+        timer_servo = 0;
+      }
+      timer_servo++;
+    }
+
+    int addServo(servoTimer_t * s){
+      if (servoCount<MAX_ZEPHYR_SERVOS){
+        for (uint8_t i = 0; i<MAX_ZEPHYR_SERVOS; i++){
+          if (servos[i]!=nullptr && servos[i]->pin==s->pin){
+            return i;
+          }
+      }
+      for (uint8_t i = 0; i<MAX_ZEPHYR_SERVOS; i++){
+        if (servos[i]==nullptr){
+          servos[i]=s;
+          servoCount++;
+          return i;
+        }
+      }
+      }
+      else{
+        return -1;
+      }
+      return -2;
+    }
+
+    int removeServo(int index){
+      if (index<MAX_ZEPHYR_SERVOS){
+        delete servos[index];
+        servos[index]=nullptr;
+        servoCount--;
+        return index;
+      }
+      else{
+        return -1;
+      }
+    }
+
+    void writeMicroseconds(int index, int value){
+      if (servos[index]!=nullptr){
+        servos[index]->position_tick = value/servo_timer_base_us_tick;
+      }
+    }
+
+    uint32_t getMin(int index){
+      if (servos[index]!=nullptr){
+        return servos[index]->min;
+      }
+      return MIN_PULSE_WIDTH;
+    }
+
+    uint32_t getMax(int index){
+      if (servos[index]!=nullptr){
+        return servos[index]->max;
+      }
+      return MAX_PULSE_WIDTH;
+    }
+
+    uint32_t readMicroseconds(int index){
+      if (servos[index]!=nullptr){
+        return servos[index]->position_tick*servo_timer_base_us_tick;
+      }
+      return 0;
+    }
+};
+
+static ServoTimerHandler servo_handle;
+
+
+Servo::Servo(){
+  servo_handle.initTimer();
+  servoIndex = 255;
+}
+
+uint8_t Servo::attach(int pin){
+  return this->attach(pin, MIN_PULSE_WIDTH , MAX_PULSE_WIDTH );
+}
+
+uint8_t Servo::attach(int pin, int min, int max){
+  pinMode(pin, OUTPUT);
+  servoTimer_t * tmp_servo = new servoTimer_t();
+  tmp_servo->pin = pin;
+  tmp_servo->min = min;
+  tmp_servo->max = max;
+  servoIndex = servo_handle.addServo(tmp_servo);
+  this->min = servo_handle.getMin(servoIndex)/4;
+  this->max = servo_handle.getMax(servoIndex)/4;
+  return 0;
+}
+
+
+void Servo::detach(){
+  servo_handle.removeServo(servoIndex);
+  servoIndex = 255;
+}
+
+void Servo::write(int value){
+  servo_handle.writeMicroseconds(servoIndex, map(value, 0, 180, servo_handle.getMin(servoIndex), servo_handle.getMax(servoIndex)));
+}
+
+void Servo::writeMicroseconds(int value){
+  servo_handle.writeMicroseconds(servoIndex, value);
+}
+
+int Servo::read(){
+  return map(servo_handle.readMicroseconds(servoIndex), servo_handle.getMin(servoIndex), servo_handle.getMax(servoIndex), 0, 180);
+}
+
+int Servo::readMicroseconds(){
+  return servo_handle.readMicroseconds(servoIndex);
+}
+
+bool Servo::attached(){
+  if (servoIndex==255){
+    return false;
+  }
+  else{
+    return true;
+  }
+}
+
+#endif

src/zephyr/ServoTimers.h

@@ -0,0 +1,6 @@
+#define MAX_ZEPHYR_SERVOS 16
+
+#define TIMER DT_NODELABEL(counter_servo)
+
+const uint32_t servo_timer_base_us_tick = 4; 
+const uint32_t servo_timer_end_tick = 20000/servo_timer_base_us_tick;