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:
9:d3fb631890d7
Parent:
8:f1432e9af6c8
Child:
10:4b88be251088
--- a/main.cpp	Tue Aug 02 19:42:17 2016 +0000
+++ b/main.cpp	Sat Aug 13 11:56:02 2016 +0000
@@ -5,7 +5,6 @@
 DigitalOut  myled(LED1);
  
 int main() {
-    confSysClock();     //Configure system clock (72MHz HSE clock, 48MHz USB clock)
     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