Added ability to reset and relaunch core 1 (#493)

cores/rp2040/RP2040Support.h

@@ -94,6 +94,18 @@ public:
         // once otherIdled == false.
     }
 
+    void clear() {
+        uint32_t val;
+
+        while (queue_try_remove(&_queue[0], &val)) {
+            tight_loop_contents();
+        }
+
+        while (queue_try_remove(&_queue[1], &val)) {
+            tight_loop_contents();
+        }
+    }
+
 private:
     static void __no_inline_not_in_flash_func(_irq)() {
         multicore_fifo_clear_irq();
@@ -118,6 +130,8 @@ private:
 
 class RP2040;
 extern RP2040 rp2040;
+extern "C" void main1();
+
 class RP2040 {
 public:
     RP2040() {
@@ -172,6 +186,12 @@ public:
         fifo.resumeOtherCore();
     }
 
+    void restartCore1() {
+        multicore_reset_core1();
+        fifo.clear();
+        multicore_launch_core1(main1);
+    }
+
     // Multicore comms FIFO
     _MFIFO fifo;
 

cores/rp2040/main.cpp

@@ -41,7 +41,7 @@ void initVariant() { }
 // Optional 2nd core setup and loop
 extern void setup1() __attribute__((weak));
 extern void loop1() __attribute__((weak));
-static void main1() {
+extern "C" void main1() {
     rp2040.fifo.registerCore();
     if (setup1) {
         setup1();