The API for a Stepper Motor providing position and speed control for an Automotive Gauge Stepper Motor.

Revision:
0:c346170974bc
```--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Stepper_Motor_X27168.cpp	Tue Oct 20 00:36:06 2015 +0000
@@ -0,0 +1,98 @@
+#include "StepperMotor_X27168.h"
+
+StepperMotor_X27168::StepperMotor_X27168(PinName A_f, PinName A_r, PinName B_f, PinName B_r)
+            :motor_control(A_f, A_r, B_f, B_r)
+{
+        motor_control = 0x0;
+        max_position = MAX_POS;
+        speed = DEFAULT_SPEED;
+        cur_state = STOP_MOTOR;
+        cur_position = 0;
+}
+
+StepperMotor_X27168::StepperMotor_X27168(PinName A_f, PinName A_r, PinName B_f, PinName B_r, int init_step_position)
+            :motor_control(A_f, A_r, B_f, B_r)
+{
+        StepperMotor_X27168(A_f, A_r, B_f, B_r);
+        step_position(init_step_position);
+}
+
+void StepperMotor_X27168::set_speed(float s) {
+    speed = s;
+}
+
+int StepperMotor_X27168::get_speed() {
+    return speed;
+}
+
+void StepperMotor_X27168::set_max_position(int p) {
+    if(p<MAX_POS) {
+        max_position = p;
+    }
+}
+
+int StepperMotor_X27168::get_max_position() {
+    return max_position;
+}
+
+int StepperMotor_X27168::step(int dir) {
+    if(dir==2)
+        cur_state = STOP_MOTOR;
+    else if(dir == 0) {
+        cur_state = (Polarity)((cur_state+1)%4);
+
+        if(cur_position <= MAX_POS) {
+            cur_position++;
+        }
+    }
+    else if (dir == 1) {
+        cur_state = (Polarity)((cur_state-1)%4);
+        cur_state = (Polarity)(cur_state == 255 ? cur_state + 4 : cur_state);
+
+        if(cur_position>= 0) {
+            cur_position--;
+        }
+    }
+    else
+        return -1;
+
+    switch (cur_state) {
+        case 0:
+            motor_control = 0x1;
+            break;
+        case 1:
+            motor_control = 0x4;
+            break;
+        case 2:
+            motor_control = 0x2;
+            break;
+        case 3:
+            motor_control = 0x8;
+            break;
+        case 4:
+            motor_control = 0x0;
+            break;
+    }
+    wait(1.0/speed);
+    return cur_position;
+}
+
+void StepperMotor_X27168::step_position(int pos) {
+    if(pos > max_position)
+        pos = max_position;
+    else if(pos < 0)
+        pos = 0;
+
+    while(cur_position < pos) {
+        step(0);
+    }
+    while(cur_position > pos) {
+        step(1);
+    }
+
+    step(2);
+}
+
+void StepperMotor_X27168::angle_position(float angle) {
+    step_position(int(angle*2));
+}
\ No newline at end of file
```