From 281c180722fecc06c73b0e0ffeb7f7541c51bee3 Mon Sep 17 00:00:00 2001
From: 0xc0170 <c0170@rocketmail.com>
Date: Fri, 20 Nov 2015 08:12:29 +0000
Subject: [PATCH] InterrupIn - attach with null clears the function pointer

---
 libraries/mbed/common/InterruptIn.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libraries/mbed/common/InterruptIn.cpp b/libraries/mbed/common/InterruptIn.cpp
index 8692124c14..92f70f2a5e 100644
--- a/libraries/mbed/common/InterruptIn.cpp
+++ b/libraries/mbed/common/InterruptIn.cpp
@@ -44,6 +44,7 @@ void InterruptIn::rise(void (*fptr)(void)) {
         _rise.attach(fptr);
         gpio_irq_set(&gpio_irq, IRQ_RISE, 1);
     } else {
+        _rise.attach(NULL);
         gpio_irq_set(&gpio_irq, IRQ_RISE, 0);
     }
 }
@@ -53,6 +54,7 @@ void InterruptIn::fall(void (*fptr)(void)) {
         _fall.attach(fptr);
         gpio_irq_set(&gpio_irq, IRQ_FALL, 1);
     } else {
+        _fall.attach(NULL);
         gpio_irq_set(&gpio_irq, IRQ_FALL, 0);
     }
 }