[HAL] Make RPi Pico tone helpers static

src/hal/RPiPico/PicoHal.cpp

@@ -0,0 +1,45 @@
+#include "PicoHal.h"
+
+// pre-calculated pulse-widths for 1200 and 2200Hz
+// we do this to save calculation time (see https://github.com/khoih-prog/RP2040_PWM/issues/6)
+#define SLEEP_1200 416.666
+#define SLEEP_2200 227.272
+
+static uint32_t toneLoopPin;
+static unsigned int toneLoopFrequency;
+static unsigned long toneLoopDuration;
+
+// === NOTE ===
+// The tone(...) implementation uses the second core on the RPi Pico. This is to diminish as much 
+// jitter in the output tones as possible.
+
+static void toneLoop() {
+  gpio_set_dir(toneLoopPin, GPIO_OUT);
+
+  uint32_t sleep_dur;
+  if(toneLoopFrequency == 1200) {
+    sleep_dur = SLEEP_1200;
+  } else if(toneLoopFrequency == 2200) {
+    sleep_dur = SLEEP_2200;
+  } else {
+    sleep_dur = 500000 / toneLoopFrequency;
+  }
+
+  // tone bitbang
+  while(1) {
+    gpio_put(toneLoopPin, 1);
+    sleep_us(sleep_dur);
+    gpio_put(toneLoopPin, 0);
+    sleep_us(sleep_dur);
+    tight_loop_contents();
+  }
+}
+
+void PicoHal::tone(uint32_t pin, unsigned int frequency, unsigned long duration) {
+  // tones on the Pico are generated using bitbanging. This process is offloaded to the Pico's second core
+  multicore_reset_core1();
+  toneLoopPin = pin;
+  toneLoopFrequency = frequency;
+  toneLoopDuration = duration;
+  multicore_launch_core1(toneLoop);
+}

src/hal/RPiPico/PicoHal.h

@@ -12,42 +12,6 @@
 #include "hardware/clocks.h"
 #include "pico/multicore.h"
 
-uint32_t toneLoopPin;
-unsigned int toneLoopFrequency;
-unsigned long toneLoopDuration;
-
-// pre-calculated pulse-widths for 1200 and 2200Hz
-// we do this to save calculation time (see https://github.com/khoih-prog/RP2040_PWM/issues/6)
-#define SLEEP_1200 416.666
-#define SLEEP_2200 227.272
-
-// === NOTE ===
-// The tone(...) implementation uses the second core on the RPi Pico. This is to diminish as much 
-// jitter in the output tones as possible.
-
-void toneLoop(){
-  gpio_set_dir(toneLoopPin, GPIO_OUT);
-
-  uint32_t sleep_dur;
-  if (toneLoopFrequency == 1200) {
-    sleep_dur = SLEEP_1200;
-  } else if (toneLoopFrequency == 2200) {
-    sleep_dur = SLEEP_2200;
-  } else {
-    sleep_dur = 500000 / toneLoopFrequency;
-  }
-
-
-  // tone bitbang
-  while(1){
-    gpio_put(toneLoopPin, 1);
-    sleep_us(sleep_dur);
-    gpio_put(toneLoopPin, 0);
-    sleep_us(sleep_dur);
-    tight_loop_contents();
-  }
-}
-
 // create a new Raspberry Pi Pico hardware abstraction 
 // layer using the Pico SDK
 // the HAL must inherit from the base RadioLibHal class
@@ -148,14 +112,7 @@ public:
     return (this->micros() - start);
   }
 
-  void tone(uint32_t pin, unsigned int frequency, unsigned long duration = 0) override {
-    // tones on the Pico are generated using bitbanging. This process is offloaded to the Pico's second core
-    multicore_reset_core1();
-    toneLoopPin = pin;
-    toneLoopFrequency = frequency;
-    toneLoopDuration = duration;
-    multicore_launch_core1(toneLoop);
-  }
+  void tone(uint32_t pin, unsigned int frequency, unsigned long duration = 0) override;
 
   void noTone(uint32_t pin) override {
     multicore_reset_core1();