1  # The MIT License (MIT)
 2  #
 3  # Copyright (c) 2018 Carter Nelson for Adafruit Industries
 4  #
 5  # Permission is hereby granted, free of charge, to any person obtaining a copy
 6  # of this software and associated documentation files (the "Software"), to deal
 7  # in the Software without restriction, including without limitation the rights
 8  # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 9  # copies of the Software, and to permit persons to whom the Software is
10  # furnished to do so, subject to the following conditions:
11  #
12  # The above copyright notice and this permission notice shall be included in
13  # all copies or substantial portions of the Software.
14  #
15  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18  # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20  # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
21  # THE SOFTWARE.
22  """
23  `ads1015`
24  ====================================================
25  
26  CircuitPython driver for ADS1015 ADCs.
27  
28  * Author(s): Carter Nelson
29  """
30  import struct
31  
32  # pylint: disable=unused-import
33  from .ads1x15 import ADS1x15, Mode
34  
35  # Data sample rates
36  _ADS1015_CONFIG_DR = {
37      128: 0x0000,
38      250: 0x0020,
39      490: 0x0040,
40      920: 0x0060,
41      1600: 0x0080,
42      2400: 0x00A0,
43      3300: 0x00C0,
44  }
45  
46  # Pins
47  P0 = 0
48  P1 = 1
49  P2 = 2
50  P3 = 3
51  
52  
53  class ADS1015(ADS1x15):
54      """Class for the ADS1015 12 bit ADC."""
55  
56      @property
57      def bits(self):
58          """The ADC bit resolution."""
59          return 12
60  
61      @property
62      def rates(self):
63          """Possible data rate settings."""
64          r = list(_ADS1015_CONFIG_DR.keys())
65          r.sort()
66          return r
67  
68      @property
69      def rate_config(self):
70          """Rate configuration masks."""
71          return _ADS1015_CONFIG_DR
72  
73      def _data_rate_default(self):
74          return 1600
75  
76      def _conversion_value(self, raw_adc):
77          raw_adc = raw_adc.to_bytes(2, "big")
78          value = struct.unpack(">h", raw_adc)[0]
79          return value >> 4