Update core_pins.h

teensy3/core_pins.h

@@ -40,6 +40,8 @@
 #define INPUT		0
 #define OUTPUT		1
 #define INPUT_PULLUP	2
+#define INPUT_PULLDOWN   3
+#define OUTPUT_OPENDRAIN 4
 #define LSBFIRST	0
 #define MSBFIRST	1
 #define _BV(n)		(1<<(n))