/
ADS1115.py
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/
ADS1115.py
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# Import of Librarys
from machine import I2C, Pin
import utime
# Register variables
_REGISTER_MASK = 0x03
_REGISTER_CONVERT = 0x00
_REGISTER_CONFIG = 0x01
_REGISTER_LOWTHRESH = 0x02
_REGISTER_HITHRESH = 0x03
_OS_MASK = 0x8000
_OS_SINGLE = 0x8000 # Write: Set to start a single - conversion
_OS_BUSY = 0x0000 # Read: Bit = 0 when conversion is in progress
_OS_NOTBUSY = 0x8000 # Read: Bit = 1 when no conversion is in progress
# Channel variables
_MUX_MASK = 0x7000
_MUX_DIFF_0_1 = 0x0000 # Differential P = AIN0, N = AIN1 (default)
_MUX_DIFF_0_3 = 0x1000 # Differential P = AIN0, N = AIN3
_MUX_DIFF_1_3 = 0x2000 # Differential P = AIN1, N = AIN3
_MUX_DIFF_2_3 = 0x3000 # Differential P = AIN2, N = AIN3
_MUX_SINGLE_0 = 0x4000 # Single - ended AIN0
_MUX_SINGLE_1 = 0x5000 # Single - ended AIN1
_MUX_SINGLE_2 = 0x6000 # Single - ended AIN2
_MUX_SINGLE_3 = 0x7000 # Single - ended AIN3
# Gain variables
_PGA_MASK = 0x0E00
_PGA_6_144V = 0x0000 # + /-6.144V range = Gain 2/3
_PGA_4_096V = 0x0200 # + /-4.096V range = Gain 1
_PGA_2_048V = 0x0400 # + /-2.048V range = Gain 2 (default)
_PGA_1_024V = 0x0600 # + /-1.024V range = Gain 4
_PGA_0_512V = 0x0800 # + /-0.512V range = Gain 8
_PGA_0_256V = 0x0A00 # + /-0.256V range = Gain 16
# Mode variables
_MODE_MASK = 0x0100
_MODE_CONTIN = 0x0000 # Continuous conversion mode
_MODE_SINGLE = 0x0100 # Power - down single - shot mode (default)
# Samplerate variables
_DR_MASK = 0x00E0 # ADS1115
_DR_128SPS = 0x0000 # 8 samples per second
_DR_250SPS = 0x0020 # 16 samples per second
_DR_490SPS = 0x0040 # 32 samples per second
_DR_920SPS = 0x0060 # 64 samples per second
_DR_1600SPS = 0x0080 # 128 samples per second (default)
_DR_2400SPS = 0x00A0 # 250 samples per second
_DR_3300SPS = 0x00C0 # 475 samples per second
_DR_860SPS = 0x00E0 # 860 samples per Second
_CMODE_MASK = 0x0010
_CMODE_TRAD = 0x0000 # Traditional comparator with hysteresis (default)
_CMODE_WINDOW = 0x0010 # Window comparator
_CPOL_MASK = 0x0008
_CPOL_ACTVLOW = 0x0000 # ALERT / RDY pin is low when active (default)
_CPOL_ACTVHI = 0x0008 # ALERT / RDY pin is high when active
_CLAT_MASK = 0x0004 # Determines if ALERT / RDY pin latches once asserted
_CLAT_NONLAT = 0x0000 # Non - latching comparator (default)
_CLAT_LATCH = 0x0004 # Latching comparator
_CQUE_MASK = 0x0003
_CQUE_1CONV = 0x0000 # Assert ALERT / RDY after one conversions
_CQUE_2CONV = 0x0001 # Assert ALERT / RDY after two conversions
_CQUE_4CONV = 0x0002 # Assert ALERT / RDY after four conversions
_CQUE_NONE = 0x0003 # Disable the comparator and put ALERT / RDY in high state (default)
# List of all usable gains
_GAINS = [
_PGA_6_144V, # 2 / 3x
_PGA_4_096V, # 1x
_PGA_2_048V, # 2x (default)
_PGA_1_024V, # 4x
_PGA_0_512V, # 8x
_PGA_0_256V # 16x
]
# List of voltage values corresponding to the list of usable gains
_GAINS_V = [
6.144, # 2 / 3x
4.096, # 1x
2.048, # 2x (default)
1.024, # 4x
0.512, # 8x
0.256 # 16x
]
# List of the different usable channels
_CHANNELS = [ # CH1|CH2
_MUX_SINGLE_0, # (0, None) (default)
_MUX_SINGLE_1, # (1, None)
_MUX_SINGLE_2, # (2, None)
_MUX_SINGLE_3, # (3, None)
_MUX_DIFF_0_1, # (0, 1)
_MUX_DIFF_0_3, # (0, 3)
_MUX_DIFF_1_3, # (1, 3)
_MUX_DIFF_2_3, # (2, 3)
]
# List of all usable sample rates
_RATES = [
_DR_128SPS, # 8 samples per second
_DR_250SPS, # 16 samples per second
_DR_490SPS, # 32 samples per second
_DR_920SPS, # 64 samples per second
_DR_1600SPS, # 128 samples per second (default)
_DR_2400SPS, # 250 samples per second
_DR_3300SPS, # 475 samples per second
_DR_860SPS # 860 samples per Second
]
i2c = I2C(0, sda = Pin(0), scl = Pin(1), freq = 100000)
utime.sleep_ms(10)
# All global variables used in the library, as well as some predefined variables that serve as default values.
adsaddress = 0x48
adsgain = _GAINS[2]
adsrate = _RATES[4]
adsmode = _MODE_CONTIN
adsgainv = 2
temp2 = bytearray(2)
# Initialization of the ADS based on user input.
def init(adr, gain, rate, mode):
global adsaddress
adsaddress = adr
setGain(gain)
setRate(rate)
setMode(mode)
# Change the gains based on the user input.
def setGain(gain):
global adsgain
global adsgainv
adsgain = _GAINS[gain]
adsgainv = gain
# Change the sampling rate based on user input.
def setRate(rate):
global adsrate
adsrate = _RATES[rate]
# Change the mode based on user input.
def setMode(mode = True):
global adsmode
if (mode):
adsmode = _MODE_SINGLE
else:
adsmode = _MODE_CONTIN
# Write the desired 16-bit value into the register.
def _write_register(reg, val):
temp2[0] = val >> 8
temp2[1] = val & 0xff
i2c.writeto_mem(adsaddress, reg, temp2)
# Read the 16-bit register value to be returned.
def _read_register(reg):
i2c.readfrom_mem_into(adsaddress, reg, temp2)
return (temp2[0] << 8) | temp2[1]
# Reads any raw value (raw) either from the previously specified channel or from another variable and converts it to voltages.
def raw_to_v(raw):
v_p_b = _GAINS_V[adsgainv] / 32767
return round(raw * v_p_b, 2)
# Reads the specified channel of the ADS1115.
def read(chan):
# Linking of all required data by the bitwise operator 'OR ('|')'.
config = 0x0000
config |= _CHANNELS[chan]
config |= adsgain
config |= adsrate
config |= adsmode
config |= _CQUE_NONE
# Send the required data to the specified register.
_write_register(_REGISTER_CONFIG, config)
while not _read_register(_REGISTER_CONFIG) & _OS_NOTBUSY:
break
# Reading the returned data.
res = _read_register(_REGISTER_CONVERT)
if (res < 32768):
return res
else:
res = res - 65469
return res
# Reading multiple ADS1115 channels at once
def readMulti(start, end):
res1 = 0
res2 = 0
res3 = 0
res4 = 0
if (start > 4): start = 4
if (start < 0): start = 0
if (end > 4): end = 4
if (end < 0): end = 0
for x in range (start, end):
if (x == 0):
res1 = read(x)
utime.sleep_ms(25)
if (x == 1):
res2 = read(x)
utime.sleep_ms(25)
if (x == 2):
res3 = read(x)
utime.sleep_ms(25)
if (x == 3):
res4 = read(x)
utime.sleep_ms(25)
return res1, res2, res3, res4