diff --git a/teensy/teensy_hal.c b/teensy/teensy_hal.c
index 8996c27c9..4fcf99922 100644
--- a/teensy/teensy_hal.c
+++ b/teensy/teensy_hal.c
@@ -2,6 +2,7 @@
 #include <string.h>
 
 #include "py/mpstate.h"
+#include "py/runtime.h"
 #include "py/mphal.h"
 #include "usb.h"
 #include "uart.h"
@@ -58,3 +59,7 @@ void mp_hal_stdout_tx_strn_cooked(const char *str, size_t len) {
 
 void mp_hal_gpio_clock_enable(GPIO_TypeDef *gpio) {
 }
+
+void extint_register_pin(const void *pin, uint32_t mode, int hard_irq, mp_obj_t callback_obj) {
+    mp_not_implemented(NULL);
+}
diff --git a/teensy/teensy_hal.h b/teensy/teensy_hal.h
index 80f320e0c..162effa85 100644
--- a/teensy/teensy_hal.h
+++ b/teensy/teensy_hal.h
@@ -57,6 +57,8 @@ typedef struct {
 #define GPIO_MODE_AF_PP     ((uint32_t)0x00000002)
 #define GPIO_MODE_AF_OD     ((uint32_t)0x00000012)
 #define GPIO_MODE_ANALOG    ((uint32_t)0x00000003)
+#define GPIO_MODE_IT_RISING ((uint32_t)1)
+#define GPIO_MODE_IT_FALLING ((uint32_t)2)
 
 #define IS_GPIO_MODE(MODE) (((MODE) == GPIO_MODE_INPUT)              ||\
                             ((MODE) == GPIO_MODE_OUTPUT_PP)          ||\