Simple UI layer -- responsible for clearing screen and setting basics

UI.cpp

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+#include <M5StickC.h>
+#include "Kernel.h"
+
+int UI(int pid, unsigned int signal)
+{
+  if (signal & SIGNAL_START)
+  {
+    Kernel_signal_mask(pid, SIGNAL_START | SIGNAL_STOP | SIGNAL_REDRAW);
+  }
+  if (signal & SIGNAL_STOP)
+  {
+    return 255;
+  }
+  if (signal & SIGNAL_REDRAW)
+  {
+    M5.Lcd.fillScreen(TFT_DARKGREY);
+    M5.Lcd.setRotation(3);
+    M5.Lcd.setTextColor(TFT_WHITE, TFT_DARKGREY);
+  }
+
+  return 0;
+}

UI.h

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+
+int UI(int pid, unsigned int signal);