Merge pull request #20 from caternuson/i2c_speedup

I2C Speedup

Author: caternuson

adafruit_nunchuk.py

@@ -31,17 +31,27 @@
 __version__ = "0.0.0-auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_Nunchuk.git"
 
-_DEFAULT_ADDRESS = 0x52
 _I2C_INIT_DELAY = 0.1
-_I2C_READ_DELAY = 0.01
 
 
 class Nunchuk:
-    """Class which provides interface to Nintendo Nunchuk controller."""
-
-    def __init__(self, i2c, address=_DEFAULT_ADDRESS):
-        self.buffer = bytearray(6)
+    """
+    Class which provides interface to Nintendo Nunchuk controller.
+
+    :param i2c: The `busio.I2C` object to use.
+    :param address: The I2C address of the device. Default is 0x52.
+    :type address: int, optional
+    :param i2c_read_delay: The time in seconds to pause between the
+        I2C write and read. This needs to be at least 200us. A
+        conservative default of 2000us is used since some hosts may
+        not be able to achieve such timing.
+    :type i2c_read_delay: float, optional
+    """
+
+    def __init__(self, i2c, address=0x52, i2c_read_delay=0.002):
+        self.buffer = bytearray(8)
         self.i2c_device = I2CDevice(i2c, address)
+        self._i2c_read_delay = i2c_read_delay
         time.sleep(_I2C_INIT_DELAY)
         with self.i2c_device as i2c_dev:
             # turn off encrypted data
@@ -83,9 +93,7 @@ def _read_data(self):
 
     def _read_register(self, address):
         with self.i2c_device as i2c:
-            time.sleep(_I2C_READ_DELAY)
             i2c.write(address)
-            time.sleep(_I2C_READ_DELAY)
+            time.sleep(self._i2c_read_delay)  # at least 200us
             i2c.readinto(self.buffer)
-        time.sleep(_I2C_READ_DELAY)
         return self.buffer