Thanks to Zoltan Hudak publish the way to use STM32F103c8t6 on mbed. Now, this example can let you use it with a encoder.

Dependencies:   QEI mbed-STM32F103C8T6 mbed

Fork of STM32F103C8T6_Hello by Zoltan Hudak

Revision:
11:b6d4d3f90831
Parent:
10:4b88be251088
--- a/main.cpp	Thu Sep 15 18:40:03 2016 +0000
+++ b/main.cpp	Tue May 23 16:45:28 2017 +0000
@@ -1,10 +1,12 @@
 #include "stm32f103c8t6.h"
 #include "mbed.h"
-  
+#include "QEI.h"
+
 int main() {
     confSysClock();     //Configure system clock (72MHz HSE clock, 48MHz USB clock)
     
     Serial      pc(PA_2, PA_3);
+    QEI wheel (PB_9, PB_8, NC, 624);
     DigitalOut  myled(LED1);
     
     while(1) {
@@ -14,7 +16,6 @@
         wait_ms(200);   // 200 millisecond
         myled = 1;      // turn the LED off
         wait_ms(1000);  // 1000 millisecond
-        pc.printf("Blink\r\n");
+        pc.printf("Pulses is: %i\n", wheel.getPulses());//pc.printf("Blink\r\n");
     }
 }
- 
\ No newline at end of file