Try to use digitalIn and pwm on the same pin. It is not work

Dependencies:   mbed

Revision:
0:66e4c4d304b0
diff -r 000000000000 -r 66e4c4d304b0 main.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Feb 16 12:13:02 2017 +0000
@@ -0,0 +1,21 @@
+#include "mbed.h"
+
+
+
+
+PwmOut mypwm(PA_4);
+DigitalInOut din(PA_4);
+
+//DigitalIn button(PA_0);
+//DigitalOut myled(PC_9);
+
+int main() {
+    mypwm.period(0.01);
+    float pulsewidth = 0;
+    while(1) {
+        if (pulsewidth>=1.0) pulsewidth=0;    
+        mypwm.write(pulsewidth+=0.1);
+//        myled = !myled;
+        wait(1);
+    }
+}