Add PWM_StepperControl example

Credits of Paul van Dinther (https://github.com/dinther). Check #16

PWM_StepperControl/PWM_StepperControl.ino

@@ -0,0 +1,75 @@
+/****************************************************************************************************************************
+  PWM_StepperControl.ino
+  For RP2040 boards
+  Written by Khoi Hoang
+
+  Built by Khoi Hoang https://github.com/khoih-prog/RP2040_PWM
+  Licensed under MIT license
+
+  The RP2040 PWM block has 8 identical slices. Each slice can drive two PWM output signals, or measure the frequency
+  or duty cycle of an input signal. This gives a total of up to 16 controllable PWM outputs. All 30 GPIO pins can be driven
+  by the PWM block
+
+  Credits of Paul van Dinther (https://github.com/dinther). Check https://github.com/khoih-prog/RP2040_PWM/issues/16
+*****************************************************************************************************************************/
+
+#define _PWM_LOGLEVEL_        1
+
+#if ( defined(ARDUINO_NANO_RP2040_CONNECT) || defined(ARDUINO_RASPBERRY_PI_PICO) || defined(ARDUINO_ADAFRUIT_FEATHER_RP2040) || \
+      defined(ARDUINO_GENERIC_RP2040) ) && defined(ARDUINO_ARCH_MBED)
+
+  #if(_PWM_LOGLEVEL_>3)
+    #warning USING_MBED_RP2040_PWM
+  #endif
+
+#elif ( defined(ARDUINO_ARCH_RP2040) || defined(ARDUINO_RASPBERRY_PI_PICO) || defined(ARDUINO_ADAFRUIT_FEATHER_RP2040) || \
+        defined(ARDUINO_GENERIC_RP2040) ) && !defined(ARDUINO_ARCH_MBED)
+
+  #if(_PWM_LOGLEVEL_>3)
+    #warning USING_RP2040_PWM
+  #endif
+#else
+  #error This code is intended to run on the RP2040 mbed_nano, mbed_rp2040 or arduino-pico platform! Please check your Tools->Board setting.
+#endif
+
+#include <RP2040_PWM.h>
+
+RP2040_PWM* stepper;
+float frequency;
+float dutyCycle;
+#define STEP_PIN      8
+#define DIR_PIN       9
+
+void setSpeed(int speed)
+{
+  //  Set the frequency of the PWM output and a duty cycle of 50%
+  digitalWrite(DIR_PIN, (speed < 0));
+  stepper->setPWM(STEP_PIN, abs(speed), 50);  
+}
+
+void setup() 
+{
+  pinMode(DIR_PIN, OUTPUT);
+
+  Serial.begin(115200);
+
+  while (!Serial && millis() < 5000);
+
+  delay(100);
+
+  Serial.print(F("\nStarting PWM_DynamicFreq on "));
+  Serial.println(BOARD_NAME);
+  Serial.println(RP2040_PWM_VERSION);
+
+  //  Create PWM object and passed just a random frequency of 500 in it
+  //  The duty cycle is how you turn the motor on and off
+  stepper = new RP2040_PWM(STEP_PIN, 500, 0);
+}
+
+void loop() 
+{
+  setSpeed(1000);
+  delay(3000);
+  setSpeed(-500);
+  delay(3000);
+}