--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/.hgignore	Fri Jun 10 23:23:56 2016 +0200
@@ -0,0 +1,14 @@
+syntax: glob
+*.pyc
+*~
+.*.swp
+docs/_build/*
+build/*
+dist/*
+bin/*
+lib/*
+include/*
+local
+*.egg-info
+cache/*
+*.DS_Store

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ads1015.py	Fri Jun 10 23:23:56 2016 +0200
@@ -0,0 +1,123 @@
+import ustruct
+import time
+
+
+_REGISTER_MASK = const(0x03)
+_REGISTER_CONVERT = const(0x00)
+_REGISTER_CONFIG = const(0x01)
+_REGISTER_LOWTHRESH = const(0x02)
+_REGISTER_HITHRESH = const(0x03)
+
+_OS_MASK = const(0x8000)
+_OS_SINGLE = const(0x8000)  # Write: Set to start a single-conversion
+_OS_BUSY = const(0x0000)  # Read: Bit=0 when conversion is in progress
+_OS_NOTBUSY = const(0x8000)  # Read: Bit=1 when device is not performing a conversion
+
+_MUX_MASK = const(0x7000)
+_MUX_DIFF_0_1 = const(0x0000)  # Differential P  =  AIN0, N  =  AIN1 (default)
+_MUX_DIFF_0_3 = const(0x1000)  # Differential P  =  AIN0, N  =  AIN3
+_MUX_DIFF_1_3 = const(0x2000)  # Differential P  =  AIN1, N  =  AIN3
+_MUX_DIFF_2_3 = const(0x3000)  # Differential P  =  AIN2, N  =  AIN3
+_MUX_SINGLE_0 = const(0x4000)  # Single-ended AIN0
+_MUX_SINGLE_1 = const(0x5000)  # Single-ended AIN1
+_MUX_SINGLE_2 = const(0x6000)  # Single-ended AIN2
+_MUX_SINGLE_3 = const(0x7000)  # Single-ended AIN3
+
+_PGA_MASK = const(0x0E00)
+_PGA_6_144V = const(0x0000)  # +/-6.144V range  =  Gain 2/3
+_PGA_4_096V = const(0x0200)  # +/-4.096V range  =  Gain 1
+_PGA_2_048V = const(0x0400)  # +/-2.048V range  =  Gain 2 (default)
+_PGA_1_024V = const(0x0600)  # +/-1.024V range  =  Gain 4
+_PGA_0_512V = const(0x0800)  # +/-0.512V range  =  Gain 8
+_PGA_0_256V = const(0x0A00)  # +/-0.256V range  =  Gain 16
+
+_MODE_MASK = const(0x0100)
+_MODE_CONTIN = const(0x0000)  # Continuous conversion mode
+_MODE_SINGLE = const(0x0100)  # Power-down single-shot mode (default)
+
+_DR_MASK = const(0x00E0)
+_DR_128SPS = const(0x0000)  # 128 samples per second
+_DR_250SPS = const(0x0020)  # 250 samples per second
+_DR_490SPS = const(0x0040)  # 490 samples per second
+_DR_920SPS = const(0x0060)  # 920 samples per second
+_DR_1600SPS = const(0x0080)  # 1600 samples per second (default)
+_DR_2400SPS = const(0x00A0)  # 2400 samples per second
+_DR_3300SPS = const(0x00C0)  # 3300 samples per second
+
+_CMODE_MASK = const(0x0010)
+_CMODE_TRAD = const(0x0000)  # Traditional comparator with hysteresis (default)
+_CMODE_WINDOW = const(0x0010)  # Window comparator
+
+_CPOL_MASK = const(0x0008)
+_CPOL_ACTVLOW = const(0x0000)  # ALERT/RDY pin is low when active (default)
+_CPOL_ACTVHI = const(0x0008)  # ALERT/RDY pin is high when active
+
+_CLAT_MASK = const(0x0004)  # Determines if ALERT/RDY pin latches once asserted
+_CLAT_NONLAT = const(0x0000)  # Non-latching comparator (default)
+_CLAT_LATCH = const(0x0004)  # Latching comparator
+
+_CQUE_MASK = const(0x0003)
+_CQUE_1CONV = const(0x0000)  # Assert ALERT/RDY after one conversions
+_CQUE_2CONV = const(0x0001)  # Assert ALERT/RDY after two conversions
+_CQUE_4CONV = const(0x0002)  # Assert ALERT/RDY after four conversions
+_CQUE_NONE = const(0x0003)  # Disable the comparator and put ALERT/RDY in high state (default)
+
+_GAINS = (
+    _PGA_6_144V, # 2/3x
+    _PGA_4_096V, # 1x
+    _PGA_2_048V, # 2x
+    _PGA_1_024V, # 4x
+    _PGA_0_512V, # 8x
+    _PGA_0_256V  # 16x
+)
+_CHANNELS = (_MUX_SINGLE_0, _MUX_SINGLE_1, _MUX_SINGLE_2, _MUX_SINGLE_3)
+_DIFFS = {
+    (0, 1): _MUX_DIFF_0_1,
+    (0, 3): _MUX_DIFF_0_3,
+    (1, 3): _MUX_DIFF_1_3,
+    (2, 3): _MUX_DIFF_2_3,
+}
+
+
+class ADS1015:
+    def __init__(self, i2c, address=0x48):
+        self.i2c = i2c
+        self.address = address
+        self.gain = 0 # 2/3 6.144V
+
+    def _write_register(self, register, value):
+        data = ustruct.pack('>BH', register, value)
+        self.i2c.writeto(self.address, data)
+
+    def _read_register(self, register):
+        self.i2c.start()
+        self.i2c.write(ustruct.pack('>BB', self.address << 1, register))
+        data = self.i2c.readfrom(self.address, 2)
+        return ustruct.unpack('>h', data)[0]
+
+    def read(self, channel):
+        """Read voltage between a channel and GND. Takes 1ms."""
+        self._write_register(_REGISTER_CONFIG, _CQUE_NONE | _CLAT_NONLAT |
+            _CPOL_ACTVLOW | _CMODE_TRAD | _DR_1600SPS | _MODE_SINGLE |
+            _OS_SINGLE | _GAINS[self.gain] | _CHANNELS[channel])
+        time.sleep_ms(1)
+        return self._read_register(_REGISTER_CONVERT) >> 4
+
+    def diff(self, channel1, channel2):
+        """Read voltage between two channels. Takes 1ms."""
+        self._write_register(_REGISTER_CONFIG, _CQUE_NONE | _CLAT_NONLAT |
+            _CPOL_ACTVLOW | _CMODE_TRAD | _DR_1600SPS | _MODE_SINGLE |
+            _OS_SINGLE | _GAINS[self.gain] | _DIFFS[(channel1, channel2)])
+        time.sleep_ms(1)
+        return self._read_register(_REGISTER_CONVERT) >> 4
+
+    def alert_start(self, channel, threshold):
+        """Start continuous measurement, set ALERT pin on threshold."""
+        self._write_register(_REGISTER_HITHRESH, threshold << 4)
+        self._write_register(_REGISTER_CONFIG, _CQUE_1CONV | _CLAT_LATCH |
+            _CPOL_ACTVLOW | _CMODE_TRAD | _DR_1600SPS | _MODE_CONTIN |
+            _MODE_CONTIN | _GAINS[self.gain] | _CHANNELS[channel])
+
+    def alert_read(self):
+        """Get the last reading from the continuous measurement."""
+        return self._read_register(_REGISTER_CONVERT) >> 4