Fixed a bug on the new opalib_pid_voltage_pid_calculation and the declaration...

Fixed a bug on the new opalib_pid_voltage_pid_calculation and the declaration of the opa_lib_voltage_stop

While debugging, we've noticed that the PID in this repo does not work. The issue was a non-usage of the uint32_t measurement parameter givent to the new opalib_pid_voltage_pid_calculation function. This commit corrects that.

While re-reading the opalib_pid_voltage.h we've noticed that the declaration of the opa_lib_voltage_stop function was done after the endif of the .h creation. This was also corrected.

src/opalib_pid_voltage.c

@@ -184,6 +184,7 @@ void opalib_pid_update_voltage_reference(float32_t vref)
 
 float32_t opalib_pid_voltage_pid_calculation(float32_t voltage_reference, float32_t measurement)
 {
+	V1_value = measurement;
 
 	arm_sub_f32(&Vref, &V1_value, &error_pid, 1);		// CALCULATING THE ERROR BASED ON THE REFERENCE
 

src/opalib_pid_voltage.h

@@ -91,14 +91,15 @@ float32_t opalib_pid_voltage_pid_calculation(float32_t voltage_reference, float3
 
 void opalib_pid_voltage_pwm_update(float32_t duty_cycle);
 
+/**
+ * @brief This function stops the converter by putting both timing
+ * units outputs low
+ */
+void opalib_pid_voltage_stop(void);
+
 #ifdef __cplusplus
 }
 #endif
 
 #endif // OPALIB_PID_VOLTAGE_H_
 
-/**
- * @brief This function stops the converter by putting both timing
- * units outputs low
- */
-void opalib_pid_voltage_stop(void);
\ No newline at end of file