Now builds with RadioLib!

2026-10-22 14:41:48 -05:00
parent 7b459214c8
commit 89ef1b3938
8 changed files with 461 additions and 33 deletions
@@ -0,0 +1,49 @@
+#include "PicoHal.h"
+
+#if defined(RADIOLIB_BUILD_RPI_PICO)
+
+// 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);
+}
+
+#endif