encoder_portable.py added.

README.md

@@ -141,6 +141,10 @@ There are other algorithms but this is the simplest and fastest I've encountered
 These were written for encoders producing TTL outputs. For switches, adapt the pull definition
 to provide a pull up or pull down as required.
 
+The `encoder.portable.py` version should work on all MicroPython platforms.
+Tested on ESP8266. Note that interrupt latency on the ESP8266 limits performance
+(ESP32 is probably similar).
+
 # A pseudo random number generator
 
 On the Pyboard V1.1, true random numbers may be generated rapidly with pyb.rng()

encoders/encoder_portable.py

@@ -0,0 +1,32 @@
+# Encoder Support: this version should be portable between MicroPython platforms
+# Thanks to Evan Widloski for the adaptation to the machine module
+
+from machine import Pin
+
+class Encoder(object):
+    def __init__(self, pin_x, pin_y, reverse, scale):
+        self.reverse = reverse
+        self.scale = scale
+        self.forward = True
+        self.pin_x = pin_x
+        self.pin_y = pin_y
+        self._pos = 0
+        self.x_interrupt = pin_x.irq(trigger=Pin.IRQ_RISING | Pin.IRQ_FALLING, handler=self.x_callback)
+        self.y_interrupt = pin_y.irq(trigger=Pin.IRQ_RISING | Pin.IRQ_FALLING, handler=self.y_callback)
+
+    def x_callback(self, line):
+        self.forward = self.pin_x.value() ^ self.pin_y.value() ^ self.reverse
+        self._pos += 1 if self.forward else -1
+
+    def y_callback(self, line):
+        self.forward = self.pin_x.value() ^ self.pin_y.value() ^ self.reverse ^ 1
+        self._pos += 1 if self.forward else -1
+
+    @property
+    def position(self):
+        return self._pos * self.scale
+
+    @position.setter
+    def position(self, value):
+        self._pos = value // self.scale
+