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:
10:4b88be251088
Parent:
9:d3fb631890d7
Child:
11:b6d4d3f90831
--- a/main.cpp	Sat Aug 13 11:56:02 2016 +0000
+++ b/main.cpp	Thu Sep 15 18:40:03 2016 +0000
@@ -1,17 +1,19 @@
 #include "stm32f103c8t6.h"
 #include "mbed.h"
- 
-Serial      pc(PA_2, PA_3);
-DigitalOut  myled(LED1);
- 
+  
 int main() {
+    confSysClock();     //Configure system clock (72MHz HSE clock, 48MHz USB clock)
+    
+    Serial      pc(PA_2, PA_3);
+    DigitalOut  myled(LED1);
+    
     while(1) {
         // The on-board LED is connected, via a resistor, to +3.3V (not to GND). 
         // So to turn the LED on or off we have to set it to 0 or 1 respectively
         myled = 0;      // turn the LED on
-        wait(0.2);      // 200 ms
+        wait_ms(200);   // 200 millisecond
         myled = 1;      // turn the LED off
-        wait(1.0);      // 1 sec
+        wait_ms(1000);  // 1000 millisecond
         pc.printf("Blink\r\n");
     }
 }