debugged & added example for ctx manager

circuitpython_cirque_pinnacle.py

@@ -160,13 +160,14 @@ def __enter__(self):
             # write to all internal attributes to registers
             self._rap_write_bytes(PINNACLE_SYS_CONFIG, [
                 self._sys_config, self._feed_config1, self._feed_config2])
-            self.set_adc_gain(self._sensitivity)
+            self._era_write(0x0187, self._sensitivity)
             self.detect_finger_stylus(
                 self._finger_stylus & 4, self._finger_stylus & 1, self._sample_rate)
             self._rap_write(PINNACLE_CALIBRATE_CONFIG, self._cal_config)
             self._rap_write(PINNACLE_Z_IDLE, self._z_idle_count)
             self.feed_enable = True
         self.clear_flags() # just to be sure
+        return self
 
     def __exit__(self, *exc):
         self.shutdown = True

docs/examples.rst

@@ -26,3 +26,12 @@ This example uses the Pinnacle touch controller's AnyMeas mode to fetch raw ADC
 .. literalinclude:: ../examples/cirque_pinnacle_anymeas_test.py
     :caption: examples/cirque_pinnacle_anymeas_test.py
     :linenos:
+
+Context Manager example
+-----------------------
+
+This example displays the difference in the Pinnacle ASIC's configuration registers.
+
+.. literalinclude:: ../examples/cirque_pinnacle_context_test.py
+    :caption: examples/cirque_pinnacle_context_test.py
+    :linenos:

examples/cirque_pinnacle_context_test.py

@@ -0,0 +1,46 @@
+"""This example shows the difference in register values between AnyMeas mode
+and Absolute mode using the library's context manager."""
+import board
+from digitalio import DigitalInOut
+from circuitpython_cirque_pinnacle import PinnacleTouchSPI, DataModes
+
+spi = board.SPI()
+ss_pin = DigitalInOut(board.D7)
+dr_pin = DigitalInOut(board.D2)
+dr_pin.switch_to_input()
+csn_pin = DigitalInOut(board.D5)
+
+tpad_abs = PinnacleTouchSPI(spi, ss_pin) # NOTE we did not pass the dr_pin
+tpad_abs.data_mode = DataModes.ABSOLUTE
+
+# NOTE The dr_pin is a required arg to use AnyMeas mode
+tpad_any = PinnacleTouchSPI(spi, ss_pin, dr_pin=dr_pin)
+# if dr_pin was not specified upon instantiation.
+# this command will raise an AttributeError exception
+tpad_any.data_mode = DataModes.ANYMEAS
+
+# This example accesses the hidden bus protocol functions to read and
+# print the data from the Pinnacle ASIC's configuration registers.
+# pylint: disable=protected-access
+
+print("register configured for Absolute data mode:")
+with tpad_abs as tpad:
+    for index, val in enumerate(tpad._rap_read_bytes(0x04, 11)):
+        print("\taddress {} = {}".format(hex(index + 4), hex(val)))
+
+print("\nregister configured for AnyMeas data mode:")
+with tpad_any as tpad:
+    for index, val in enumerate(tpad._rap_read_bytes(0x04, 11)):
+        print("\taddress {} = {}".format(hex(index + 4), hex(val)))
+
+# NOTE how different the register values are.
+# Registers remain unaffected when exiting the `with` block, so technically
+# tpad_abs (configured for Absolute mode) will not function properly outside
+# a new `with` block after tpad_any (configured for AnyMeas mode) was the last
+# object used in a `with` block.
+
+# NOTE the Pinnacle ASIC is powered down when exiting a `with` block
+print("Powered down?", tpad_any.shutdown)
+# ok to read the shutdown attribute here because it does not write to the
+# Pinnacle ASIC's register, but notice it is the last object used in a `with`
+# block (otherwise the data may be innaccurate).