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dhhagandhhagan
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major changes to just ADS1115
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‎ADS1115/ADS1115.py

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#!/usr/bin/python3
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import time
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import smbus
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from I2C import Adafruit_I2C
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# ===========================================================================
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# ADS1115 Class
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# ===========================================================================
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class ADS1115:
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i2c = None
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# IC Identifiers
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__IC_ADS1115 = 0x01
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# Config Register
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__ADS1115_REG_CONFIG_DR_8SPS = 0x0000 # 8 samples per second
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__ADS1115_REG_CONFIG_DR_16SPS = 0x0020 # 16 samples per second
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__ADS1115_REG_CONFIG_DR_32SPS = 0x0040 # 32 samples per second
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__ADS1115_REG_CONFIG_DR_64SPS = 0x0060 # 64 samples per second
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__ADS1115_REG_CONFIG_DR_128SPS = 0x0080 # 128 samples per second
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__ADS1115_REG_CONFIG_DR_250SPS = 0x00A0 # 250 samples per second (default)
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__ADS1115_REG_CONFIG_DR_475SPS = 0x00C0 # 475 samples per second
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__ADS1115_REG_CONFIG_DR_860SPS = 0x00E0 # 860 samples per second
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__ADS1015_REG_CONFIG_CQUE_MASK = 0x0003
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__ADS1015_REG_CONFIG_CQUE_1CONV = 0x0000 # Assert ALERT/RDY after one conversions
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__ADS1015_REG_CONFIG_CQUE_2CONV = 0x0001 # Assert ALERT/RDY after two conversions
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__ADS1015_REG_CONFIG_CQUE_4CONV = 0x0002 # Assert ALERT/RDY after four conversions
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__ADS1015_REG_CONFIG_CQUE_NONE = 0x0003 # Disable the comparator and put ALERT/RDY in high state (default)
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__ADS1015_REG_CONFIG_CMODE_MASK = 0x0010
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__ADS1015_REG_CONFIG_CMODE_TRAD = 0x0000 # Traditional comparator with hysteresis (default)
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__ADS1015_REG_CONFIG_CMODE_WINDOW = 0x0010 # Window comparator
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__ADS1015_REG_CONFIG_CPOL_MASK = 0x0008
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__ADS1015_REG_CONFIG_CPOL_ACTVLOW = 0x0000 # ALERT/RDY pin is low when active (default)
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__ADS1015_REG_CONFIG_CPOL_ACTVHI = 0x0008 # ALERT/RDY pin is high when active
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__ADS1015_REG_CONFIG_CLAT_MASK = 0x0004 # Determines if ALERT/RDY pin latches once asserted
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__ADS1015_REG_CONFIG_CLAT_NONLAT = 0x0000 # Non-latching comparator (default)
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__ADS1015_REG_CONFIG_CLAT_LATCH = 0x0004 # Latching comparator
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__ADS1015_REG_CONFIG_MODE_MASK = 0x0100
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__ADS1015_REG_CONFIG_MODE_CONTIN = 0x0000 # Continuous conversion mode
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__ADS1015_REG_CONFIG_MODE_SINGLE = 0x0100 # Power-down single-shot mode (default)
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__ADS1015_REG_CONFIG_PGA_MASK = 0x0E00
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__ADS1015_REG_CONFIG_PGA_6_144V = 0x0000 # +/-6.144V range
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__ADS1015_REG_CONFIG_PGA_4_096V = 0x0200 # +/-4.096V range
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__ADS1015_REG_CONFIG_PGA_2_048V = 0x0400 # +/-2.048V range (default)
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__ADS1015_REG_CONFIG_PGA_1_024V = 0x0600 # +/-1.024V range
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__ADS1015_REG_CONFIG_PGA_0_512V = 0x0800 # +/-0.512V range
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__ADS1015_REG_CONFIG_PGA_0_256V = 0x0A00 # +/-0.256V range
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__ADS1015_REG_CONFIG_MUX_MASK = 0x7000
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__ADS1015_REG_CONFIG_MUX_DIFF_0_1 = 0x0000 # Differential P = AIN0, N = AIN1 (default)
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__ADS1015_REG_CONFIG_MUX_DIFF_0_3 = 0x1000 # Differential P = AIN0, N = AIN3
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__ADS1015_REG_CONFIG_MUX_DIFF_1_3 = 0x2000 # Differential P = AIN1, N = AIN3
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__ADS1015_REG_CONFIG_MUX_DIFF_2_3 = 0x3000 # Differential P = AIN2, N = AIN3
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__ADS1015_REG_CONFIG_MUX_SINGLE_0 = 0x4000 # Single-ended AIN0
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__ADS1015_REG_CONFIG_MUX_SINGLE_1 = 0x5000 # Single-ended AIN1
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__ADS1015_REG_CONFIG_MUX_SINGLE_2 = 0x6000 # Single-ended AIN2
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__ADS1015_REG_CONFIG_MUX_SINGLE_3 = 0x7000 # Single-ended AIN3
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# Config Register
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__ADS1015_REG_CONFIG_OS_MASK = 0x8000
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__ADS1015_REG_CONFIG_OS_SINGLE = 0x8000 # Write: Set to start a single-conversion
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__ADS1015_REG_CONFIG_OS_BUSY = 0x0000 # Read: Bit = 0 when conversion is in progress
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__ADS1015_REG_CONFIG_OS_NOTBUSY = 0x8000 # Read: Bit = 1 when device is not performing a conversion
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# Pointer Register
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__ADS1015_REG_POINTER_MASK = 0x03
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__ADS1015_REG_POINTER_CONVERT = 0x00
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__ADS1015_REG_POINTER_CONFIG = 0x01
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__ADS1015_REG_POINTER_LOWTHRESH = 0x02
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__ADS1015_REG_POINTER_HITHRESH = 0x03
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# Dictionaries with the sampling speed values
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# These simplify and clean the code (avoid the abuse of if/elif/else clauses)
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spsADS1115 = {
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8:__ADS1115_REG_CONFIG_DR_8SPS,
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16:__ADS1115_REG_CONFIG_DR_16SPS,
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32:__ADS1115_REG_CONFIG_DR_32SPS,
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64:__ADS1115_REG_CONFIG_DR_64SPS,
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128:__ADS1115_REG_CONFIG_DR_128SPS,
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250:__ADS1115_REG_CONFIG_DR_250SPS,
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475:__ADS1115_REG_CONFIG_DR_475SPS,
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860:__ADS1115_REG_CONFIG_DR_860SPS
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}
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# Dictionariy with the programable gains
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pgaADS1x15 = {
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6144:__ADS1015_REG_CONFIG_PGA_6_144V,
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4096:__ADS1015_REG_CONFIG_PGA_4_096V,
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2048:__ADS1015_REG_CONFIG_PGA_2_048V,
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1024:__ADS1015_REG_CONFIG_PGA_1_024V,
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512:__ADS1015_REG_CONFIG_PGA_0_512V,
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256:__ADS1015_REG_CONFIG_PGA_0_256V
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}
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# Constructor
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def __init__(self, address=0x48, ic=__IC_ADS1115, debug=False):
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self.i2c = Adafruit_I2C(address)
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self.address = address
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self.debug = debug
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# Make sure the IC specified is valid
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if (ic > self.__IC_ADS1115):
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return -1
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else:
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self.ic = ic
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# Set pga value, so that getLastConversionResult() can use it,
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# any function that accepts a pga value must update this.
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self.pga = 6144
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def readADCSingleEnded(self, channel=0, pga=6144, sps=250):
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'''
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Gets a single-ended ADC reading from the specified channel in mV.
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The sample rate for this mode (single-shot) can be used to lower the noise
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(low sps) or to lower the power consumption (high sps) by duty cycling,
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see datasheet page 14 for more info.
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The pga must be given in mV, see page 13 for the supported values.
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'''
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# With invalid channel return -1
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if (channel > 3):
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return -1
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# Disable comparator, Non-latching, Alert/Rdy active low
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# traditional comparator, single-shot mode
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config = self.__ADS1015_REG_CONFIG_CQUE_NONE | \
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self.__ADS1015_REG_CONFIG_CLAT_NONLAT | \
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self.__ADS1015_REG_CONFIG_CPOL_ACTVLOW | \
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self.__ADS1015_REG_CONFIG_CMODE_TRAD | \
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self.__ADS1015_REG_CONFIG_MODE_SINGLE
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# Set sample per seconds, defaults to 250sps
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config |= self.spsADS1115.setdefault(sps, self.__ADS1115_REG_CONFIG_DR_250SPS)
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# Set PGA/voltage range, defaults to +-6.144V
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config |= self.pgaADS1x15.setdefault(pga, self.__ADS1015_REG_CONFIG_PGA_6_144V)
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self.pga = pga
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# Set the channel to be converted
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if channel == 3:
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config |= self.__ADS1015_REG_CONFIG_MUX_SINGLE_3
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elif channel == 2:
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config |= self.__ADS1015_REG_CONFIG_MUX_SINGLE_2
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elif channel == 1:
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config |= self.__ADS1015_REG_CONFIG_MUX_SINGLE_1
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else:
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config |= self.__ADS1015_REG_CONFIG_MUX_SINGLE_0
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# Set 'start single-conversion' bit
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config |= self.__ADS1015_REG_CONFIG_OS_SINGLE
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# Write config register to the ADC
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bytes = [(config >> 8) & 0xFF, config & 0xFF]
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self.i2c.writeList(self.__ADS1015_REG_POINTER_CONFIG, bytes)
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# Wait for the ADC conversion to complete
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# The minimum delay depends on the sps: delay >= 1/sps
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# We add 0.1ms to be sure
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delay = 1.0/sps+0.0001
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time.sleep(delay)
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# Read the conversion results
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result = self.i2c.readList(self.__ADS1015_REG_POINTER_CONVERT, 2)
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# Return a mV value for the ADS1115
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# (Take signed values into account as well)
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val = (result[0] << 8) | (result[1])
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if val > 0x7FFF:
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return (val - 0xFFFF)*pga/32768.0
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else:
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return ( (result[0] << 8) | (result[1]) )*pga/32768.0

‎ADS1115/I2C.py

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#!/usr/bin/python3
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import re
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import smbus
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# ===========================================================================
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# Adafruit_I2C Class
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# ===========================================================================
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class Adafruit_I2C(object):
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@staticmethod
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def getPiRevision():
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"Gets the version number of the Raspberry Pi board"
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# Revision list available at: http://elinux.org/RPi_HardwareHistory#Board_Revision_History
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try:
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with open('/proc/cpuinfo', 'r') as infile:
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for line in infile:
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# Match a line of the form "Revision : 0002" while ignoring extra
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# info in front of the revsion (like 1000 when the Pi was over-volted).
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match = re.match('Revision\s+:\s+.*(\w{4})$', line)
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if match and match.group(1) in ['0000', '0002', '0003']:
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# Return revision 1 if revision ends with 0000, 0002 or 0003.
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return 1
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elif match:
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# Assume revision 2 if revision ends with any other 4 chars.
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return 2
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# Couldn't find the revision, assume revision 0 like older code for compatibility.
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return 0
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except:
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return 0
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@staticmethod
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def getPiI2CBusNumber():
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# Gets the I2C bus number /dev/i2c#
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return 1 if Adafruit_I2C.getPiRevision() > 1 else 0
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def __init__(self, address, busnum=-1, debug=False):
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self.address = address
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# By default, the correct I2C bus is auto-detected using /proc/cpuinfo
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# Alternatively, you can hard-code the bus version below:
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# self.bus = smbus.SMBus(0); # Force I2C0 (early 256MB Pi's)
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# self.bus = smbus.SMBus(1); # Force I2C1 (512MB Pi's)
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self.bus = smbus.SMBus(busnum if busnum >= 0 else Adafruit_I2C.getPiI2CBusNumber())
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self.debug = debug
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def reverseByteOrder(self, data):
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''' Reverses the byte order of an int (16-bit) or long (32-bit) value '''
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byteCount = len(hex(data)[2:].replace('L','')[::2])
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val = 0
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for i in range(byteCount):
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val = (val << 8) | (data & 0xff)
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data >>= 8
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return val
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def errMsg(self):
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print ("Error accessing 0x%02X: Check your I2C address" % self.address)
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return -1
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def write8(self, reg, value):
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"Writes an 8-bit value to the specified register/address"
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try:
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self.bus.write_byte_data(self.address, reg, value)
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if self.debug:
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print ("I2C: Wrote 0x%02X to register 0x%02X" % (value, reg))
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except IOError:
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return self.errMsg()
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def write16(self, reg, value):
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"Writes a 16-bit value to the specified register/address pair"
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try:
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self.bus.write_word_data(self.address, reg, value)
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if self.debug:
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print ("I2C: Wrote 0x%02X to register pair 0x%02X,0x%02X" % (value, reg, reg+1))
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except IOError:
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return self.errMsg()
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def writeRaw8(self, value):
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"Writes an 8-bit value on the bus"
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try:
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self.bus.write_byte(self.address, value)
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if self.debug:
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print ("I2C: Wrote 0x%02X" % value)
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except IOError:
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return self.errMsg()
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def writeList(self, reg, list):
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"Writes an array of bytes using I2C format"
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try:
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if self.debug:
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print ("I2C: Writing list to register 0x%02X:" % reg)
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print (list)
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self.bus.write_i2c_block_data(self.address, reg, list)
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except IOError:
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return self.errMsg()
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def readList(self, reg, length):
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"Read a list of bytes from the I2C device"
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try:
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results = self.bus.read_i2c_block_data(self.address, reg, length)
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if self.debug:
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print ("I2C: Device 0x%02X returned the following from reg 0x%02X" % (self.address, reg))
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print (results)
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return results
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except IOError:
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return self.errMsg()
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def readU8(self, reg):
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"Read an unsigned byte from the I2C device"
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try:
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result = self.bus.read_byte_data(self.address, reg)
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if self.debug:
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print ("I2C: Device 0x%02X returned 0x%02X from reg 0x%02X" % (self.address, result & 0xFF, reg))
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return (result)
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except IOError:
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return self.errMsg()
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def readS8(self, reg):
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"Reads a signed byte from the I2C device"
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try:
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result = self.bus.read_byte_data(self.address, reg)
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if result > 127: result -= 256
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if self.debug:
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print ("I2C: Device 0x%02X returned 0x%02X from reg 0x%02X" % (self.address, result & 0xFF, reg))
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return result
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except IOError:
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return self.errMsg()
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def readU16(self, reg, little_endian=True):
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"Reads an unsigned 16-bit value from the I2C device"
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try:
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result = self.bus.read_word_data(self.address,reg)
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# Swap bytes if using big endian because read_word_data assumes little
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# endian on ARM (little endian) systems.
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if not little_endian:
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result = ((result << 8) & 0xFF00) + (result >> 8)
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if (self.debug):
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print ("I2C: Device 0x%02X returned 0x%04X from reg 0x%02X" % (self.address, result & 0xFFFF, reg))
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return result
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except IOError:
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return self.errMsg()
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def readS16(self, reg, little_endian=True):
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"Reads a signed 16-bit value from the I2C device"
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try:
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result = self.readU16(reg,little_endian)
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if result > 32767: result -= 65536
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return result
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except IOError:
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return self.errMsg()
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if __name__ == '__main__':
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try:
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bus = Adafruit_I2C(address=0)
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print ("Default I2C bus is accessible")
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except:
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print ("Error accessing default I2C bus")

‎ADS1115/ads1x15_ex_singleended.py

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#!/usr/bin/python3
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from ADS1115 import ADS1115
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ADS1115 = 0x01 # 16-bit ADC
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# Select the gain
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gain = 6144 # +/- 6.144V
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# Select the sample rate
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sps = 250 # 250 samples per second
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# Initialise the ADC using the default mode (use default I2C address)
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# Set this to ADS1015 or ADS1115 depending on the ADC you are using!
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adc = ADS1115(ic=ADS1115)
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# Read channel 0 in single-ended mode using the settings above
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volts = adc.readADCSingleEnded(0, gain, sps) / 1000
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print ("0".format(volts))

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