Merge pull request #6 from rtyley/add-constant-current-range-selector

Add `constant_current_range` selector for LED driving

Author: ladyada

adafruit_aw9523.py

@@ -29,6 +29,7 @@
 from adafruit_bus_device import i2c_device
 from adafruit_register.i2c_struct import ROUnaryStruct, UnaryStruct
 from adafruit_register.i2c_bit import RWBit
+from adafruit_register.i2c_bits import RWBits
 from micropython import const
 
 __version__ = "0.0.0-auto.0"
@@ -46,6 +47,12 @@
 
 # pylint: disable=invalid-name
 
+# constant_current_range options
+AW9523_4_4_RANGE = const(0) # Full range: 0 - 37 mA (typical)
+AW9523_3_4_RANGE = const(1) # 3/4 range: 0 - 27.8 mA
+AW9523_2_4_RANGE = const(2) # 2/4 range: 0 - 18.5 mA
+AW9523_1_4_RANGE = const(3) # 1/4 range: 0 - 9.3 mA
+
 
 class AW9523:
  """CircuitPython helper class for using the AW9523 GPIO expander"""
@@ -67,6 +74,9 @@ class AW9523:
  # Whether port 0 is push-pull
  port0_push_pull = RWBit(_AW9523_REG_GCR, 4)
 
+ # 256-step constant-current range selector 'ISEL' - choice of 'full' (4/4), 3/4, 2/4, or 1/4.
+ constant_current_range = RWBits(2, _AW9523_REG_GCR, 0)
+
  def __init__(self, i2c_bus, address=_AW9523_DEFAULT_ADDR, reset=True):
  self.i2c_device = i2c_device.I2CDevice(i2c_bus, address)
  self._buffer = bytearray(2)