Merge pull request #14 from caternuson/iss12

Add property style access to thresholds

Author: tannewt

adafruit_mpr121.py

@@ -80,6 +80,7 @@
 # pylint: enable=bad-whitespace
 
 class MPR121_Channel():
+    # pylint: disable=protected-access
     """Helper class to represent a touch channel on the MPR121. Not meant to
     be used directly."""
     def __init__(self, mpr121, channel):
@@ -96,6 +97,29 @@ def raw_value(self):
         """The raw touch measurement."""
         return self._mpr121.filtered_data(self._channel)
 
+    @property
+    def threshold(self):
+        """The touch threshold."""
+        buf = bytearray(1)
+        self._mpr121._read_register_bytes(MPR121_TOUCHTH_0 + 2*self._channel, buf, 1)
+        return buf[0]
+
+    @threshold.setter
+    def threshold(self, value):
+        self._mpr121._write_register_byte(MPR121_TOUCHTH_0 + 2*self._channel, value)
+
+    @property
+    def release_threshold(self):
+        """The release threshold."""
+        buf = bytearray(1)
+        self._mpr121._read_register_bytes(MPR121_RELEASETH_0 + 2*self._channel, buf, 1)
+        return buf[0]
+
+    @release_threshold.setter
+    def release_threshold(self, value):
+        self._mpr121._write_register_byte(MPR121_RELEASETH_0 + 2*self._channel, value)
+
+
 class MPR121:
     """Driver for the MPR121 capacitive touch breakout board."""
 
@@ -153,7 +177,10 @@ def reset(self):
         self._read_register_bytes(MPR121_CONFIG2, self._buffer, 1)
         if self._buffer[0] != 0x24:
             raise RuntimeError('Failed to find MPR121 in expected config state!')
-        self.set_thresholds(12, 6)
+        # Default touch and release thresholds
+        for i in range(12):
+            self._write_register_byte(MPR121_TOUCHTH_0 + 2*i, 12)
+            self._write_register_byte(MPR121_RELEASETH_0 + 2*i, 6)
         # Configure baseline filtering control registers.
         self._write_register_byte(MPR121_MHDR, 0x01)
         self._write_register_byte(MPR121_NHDR, 0x01)
@@ -173,18 +200,6 @@ def reset(self):
         # Enable all electrodes.
         self._write_register_byte(MPR121_ECR, 0x8F) # start with first 5 bits of baseline tracking
 
-    def set_thresholds(self, touch, release):
-        """Set the touch and release threshold for all inputs to the provided
-        values.  Both touch and release should be a value between 0 to 255
-        (inclusive).
-        """
-        if touch < 0 or touch > 255 or release < 0 or release > 255:
-            raise ValueError('Touch/release must be a byte value 0-255.')
-        # Set the touch and release register value for all the inputs.
-        for i in range(12):
-            self._write_register_byte(MPR121_TOUCHTH_0 + 2*i, touch)
-            self._write_register_byte(MPR121_RELEASETH_0 + 2*i, release)
-
     def filtered_data(self, pin):
         """Return filtered data register value for the provided pin (0-11).
         Useful for debugging.