add PIO1

src/main.cpp

@@ -0,0 +1,14 @@
+#include <Arduino.h>
+
+void setup() {
+  // put your setup code here, to run once:
+  pinMode(LED_BUILTIN,OUTPUT);
+}
+
+void loop() {
+  // put your main code here, to run repeatedly:
+  digitalWrite(LED_BUILTIN,HIGH);
+  delay(500);
+  digitalWrite(LED_BUILTIN,LOW);
+  delay(100);
+}