Updated pinmap.c in target_stm32f1

Author: raulMrello

libraries/mbed/targets/hal/TARGET_STM/TARGET_STM32F1/pinmap.c

@@ -177,12 +177,22 @@ void pin_mode(PinName pin, PinMode mode)
             if (pin_index < 8) {
                 if ((gpio->CRL & (0x03 << (pin_index * 4))) == 0) { // MODE bits = Input mode
                     gpio->CRL |= (0x08 << (pin_index * 4)); // Set pull-up / pull-down
+					gpio->CRL &= ~(0x08 << ((pin_index * 4)-1)); // ENSURES GPIOx_CRL.CNFx.bit0 = 0
                 }
             } else {
                 if ((gpio->CRH & (0x03 << ((pin_index % 8) * 4))) == 0) { // MODE bits = Input mode
                     gpio->CRH |= (0x08 << ((pin_index % 8) * 4)); // Set pull-up / pull-down
+					gpio->CRH &= ~(0x08 << (((pin_index % 8) * 4)-1)); // ENSURES GPIOx_CRH.CNFx.bit0 = 0
                 }
             }
+			// Now it's time to setup properly if pullup or pulldown. This is done in ODR register:
+			// set pull-up => bit=1, set pull-down => bit = 0
+			if(mode == PullUp){
+				gpio->ODR |= (0x01 << (pin_index)); // Set pull-up 
+			}
+			else{
+				gpio->ODR &= ~(0x01 << (pin_index)); // Set pull-down
+			}
             break;
         case OpenDrain:
             // Set open-drain for Output mode (General Purpose or Alternate Function)