Merge pull request #4 from jej/jej-patch-1

welcome join as developer

README.MD

@@ -5,9 +5,9 @@ import Stepper
 from machine import Pin
 s1 = Stepper.create(Pin(16,Pin.OUT),Pin(17,Pin.OUT),Pin(5,Pin.OUT),Pin(18,Pin.OUT), delay=2)
 s1.step(100)
-s1.step(100,-1)
+s1.step(100,-1) # or s1.step(-100)
 s1.angle(180)
-s1.angle(360,-1)
+s1.angle(360,-1) # or s1.angle(-360)
 ```
 function `angle` is angle, and the PIN map:
 `IN1` link `PIN_16`
@@ -15,4 +15,4 @@ function `angle` is angle, and the PIN map:
 `IN3` link `PIN_5`
 `IN4` link `PIN_18`
 My uln2003 board like this, and stepper runing:<br />
-![uln2003](img/uln2003.jpg)      ![uln2003](img/stepper.gif)<br />
+![uln2003](img/uln2003.jpg)      ![uln2003](img/stepper.gif)<br />

Stepper.py

@@ -37,6 +37,9 @@ class Stepper:
         
     def step(self, count, direction=1):
         """Rotate count steps. direction = -1 means backwards"""
+        if count<0:
+            direction = -1
+            count = -count
         for x in range(count):
             for bit in self.mode[::direction]:
                 self.pin1(bit[0])