Add UV index, refactor to adafruit_register

Author: tekktrik

adafruit_si1145.py

@@ -27,9 +27,9 @@
 """
 
 import time
-import struct
 from micropython import const
 from adafruit_bus_device import i2c_device
+from adafruit_register.i2c_struct import Struct
 
 __version__ = "0.0.0-auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_SI1145.git"
@@ -38,10 +38,15 @@
 SI1145_DEFAULT_ADDRESS = const(0x60)
 SI1145_PART_ID = const(0x00)
 SI1145_HW_KEY = const(0x07)
+_COEFF_0 = const(0x13)
+_COEFF_1 = const(0x14)
+_COEFF_2 = const(0x15)
+_COEFF_3 = const(0x16)
 SI1145_PARAM_WR = const(0x17)
 SI1145_COMMAND = const(0x18)
 SI1145_RESPONSE = const(0x20)
 SI1145_ALS_VIS_DATA0 = const(0x22)
+SI1145_UV_INDEX_DATA0 = const(0x2C)
 SI1145_PARAM_RD = const(0x2E)
 
 # Commands (for COMMAND register)
@@ -58,20 +63,30 @@
 class SI1145:
     """Driver for the SI1145 UV, IR, Visible Light Sensor."""
 
+    _device_info = Struct(SI1145_PART_ID, "<BBB")
+    _ucoeff_0 = Struct(_COEFF_0, "<B")  # TODO: const(coeff)
+    _ucoeff_1 = Struct(_COEFF_1, "<B")
+    _ucoeff_2 = Struct(_COEFF_2, "<B")
+    _ucoeff_3 = Struct(_COEFF_3, "<B")
+    _als_data = Struct(SI1145_ALS_VIS_DATA0, "<HH")
+    _aux_data = Struct(SI1145_UV_INDEX_DATA0, "<H")
+
     def __init__(self, i2c, address=SI1145_DEFAULT_ADDRESS):
-        self._i2c = i2c_device.I2CDevice(i2c, address)
+        self.i2c_device = i2c_device.I2CDevice(i2c, address)
         dev_id, dev_rev, dev_seq = self.device_info
         if dev_id != 69 or dev_rev != 0 or dev_seq != 8:
             raise RuntimeError("Failed to find SI1145.")
         self.reset()
         self._write_register(SI1145_HW_KEY, 0x17)
         self._als_enabled = True
-        self.als_enabled = True
+        self._uv_index_enabled = True
+        self.als_enabled = self._als_enabled
+        self.uv_index_enabled = self._uv_index_enabled
 
     @property
     def device_info(self):
         """A three tuple of part, revision, and sequencer ID"""
-        return tuple(self._read_register(SI1145_PART_ID, 3))
+        return self._device_info
 
     @property
     def als_enabled(self):
@@ -92,8 +107,32 @@ def als_enabled(self, enable):
     def als(self):
         """A two tuple of the Ambient Light System (ALS) visible and infrared raw sensor values."""
         self._send_command(SI1145_CMD_ALS_FORCE)
-        data = self._read_register(SI1145_ALS_VIS_DATA0, 4)
-        return struct.unpack("HH", data)
+        return self._als_data
+
+    @property
+    def uv_index_enabled(self):
+        """The UV Index system enabled state"""
+        return self._uv_index_enabled
+
+    @uv_index_enabled.setter
+    def uv_index_enabled(self, enable):
+        chlist = self._param_query(SI1145_RAM_CHLIST)
+        if enable:
+            chlist |= 0b01000000
+        else:
+            chlist &= ~0b01000000
+        self._param_set(SI1145_RAM_CHLIST, chlist)
+        self._als_enabled = enable
+
+        self._ucoeff_0 = 0x00
+        self._ucoeff_1 = 0x02
+        self._ucoeff_2 = 0x89
+        self._ucoeff_3 = 0x29
+
+    @property
+    def uv_index(self):
+        """The UV Index value"""
+        return self._aux_data[0] / 100
 
     def reset(self):
         """Perform a software reset of the firmware."""
@@ -126,12 +165,12 @@ def _send_command(self, command):
 
     def _read_register(self, register, length=1):
         buffer = bytearray(length)
-        with self._i2c as i2c:
+        with self.i2c_device as i2c:
             i2c.write_then_readinto(bytes([register]), buffer)
         return buffer[0] if length == 1 else buffer
 
     def _write_register(self, register, buffer):
         if isinstance(buffer, int):
             buffer = bytes([buffer])
-        with self._i2c as i2c:
+        with self.i2c_device as i2c:
             i2c.write(bytes([register]) + buffer)