Add support for ADS1115 16-bit ADC (#46)

jithinbp · wavicles · commit cecbc874e5fd · 2017-04-14T14:03:58.000+05:30
Partly Fixes #45 .
diff --git a/PSL/SENSORS/ADS1115.py b/PSL/SENSORS/ADS1115.py
@@ -0,0 +1,194 @@
+# -*- coding: utf-8; mode: python; indent-tabs-mode: t; tab-width:4 -*-
+from __future__ import print_function
+from numpy import int16
+import time
+try:
+    from collections import OrderedDict
+except ImportError:
+    # fallback: try to use the ordereddict backport when using python 2.6
+    from ordereddict import OrderedDict
+
+
+def connect(route,**args):
+	return ADS1115(route,**args)
+
+class ADS1115:
+	ADDRESS = 0x48 #addr pin grounded. floating
+
+	REG_POINTER_MASK    = 0x3
+	REG_POINTER_CONVERT = 0
+	REG_POINTER_CONFIG  = 1
+	REG_POINTER_LOWTHRESH=2
+	REG_POINTER_HITHRESH =3
+
+	REG_CONFIG_OS_MASK      =0x8000
+	REG_CONFIG_OS_SINGLE    =0x8000
+	REG_CONFIG_OS_BUSY      =0x0000
+	REG_CONFIG_OS_NOTBUSY   =0x8000
+
+	REG_CONFIG_MUX_MASK     =0x7000
+	REG_CONFIG_MUX_DIFF_0_1 =0x0000  # Differential P = AIN0, N = AIN1 =default)
+	REG_CONFIG_MUX_DIFF_0_3 =0x1000  # Differential P = AIN0, N = AIN3
+	REG_CONFIG_MUX_DIFF_1_3 =0x2000  # Differential P = AIN1, N = AIN3
+	REG_CONFIG_MUX_DIFF_2_3 =0x3000  # Differential P = AIN2, N = AIN3
+	REG_CONFIG_MUX_SINGLE_0 =0x4000  # Single-ended AIN0
+	REG_CONFIG_MUX_SINGLE_1 =0x5000  # Single-ended AIN1
+	REG_CONFIG_MUX_SINGLE_2 =0x6000  # Single-ended AIN2
+	REG_CONFIG_MUX_SINGLE_3 =0x7000  # Single-ended AIN3
+
+	REG_CONFIG_PGA_MASK     =0x0E00  #bits 11:9
+	REG_CONFIG_PGA_6_144V   =(0<<9)  # +/-6.144V range = Gain 2/3
+	REG_CONFIG_PGA_4_096V   =(1<<9)  # +/-4.096V range = Gain 1
+	REG_CONFIG_PGA_2_048V   =(2<<9)  # +/-2.048V range = Gain 2 =default)
+	REG_CONFIG_PGA_1_024V   =(3<<9)  # +/-1.024V range = Gain 4
+	REG_CONFIG_PGA_0_512V   =(4<<9)  # +/-0.512V range = Gain 8
+	REG_CONFIG_PGA_0_256V   =(5<<9)  # +/-0.256V range = Gain 16
+
+	REG_CONFIG_MODE_MASK    =0x0100   #bit 8
+	REG_CONFIG_MODE_CONTIN  =(0<<8)   # Continuous conversion mode
+	REG_CONFIG_MODE_SINGLE  =(1<<8)   # Power-down single-shot mode =default)
+
+	REG_CONFIG_DR_MASK      =0x00E0  
+	REG_CONFIG_DR_8SPS    =(0<<5)   #8 SPS
+	REG_CONFIG_DR_16SPS    =(1<<5)   #16 SPS
+	REG_CONFIG_DR_32SPS    =(2<<5)   #32 SPS
+	REG_CONFIG_DR_64SPS    =(3<<5)   #64 SPS
+	REG_CONFIG_DR_128SPS   =(4<<5)   #128 SPS
+	REG_CONFIG_DR_250SPS   =(5<<5)   #260 SPS
+	REG_CONFIG_DR_475SPS   =(6<<5)   #475 SPS
+	REG_CONFIG_DR_860SPS   =(7<<5)   #860 SPS
+
+	REG_CONFIG_CMODE_MASK   =0x0010
+	REG_CONFIG_CMODE_TRAD   =0x0000
+	REG_CONFIG_CMODE_WINDOW =0x0010
+
+	REG_CONFIG_CPOL_MASK    =0x0008
+	REG_CONFIG_CPOL_ACTVLOW =0x0000
+	REG_CONFIG_CPOL_ACTVHI  =0x0008
+
+	REG_CONFIG_CLAT_MASK    =0x0004
+	REG_CONFIG_CLAT_NONLAT  =0x0000
+	REG_CONFIG_CLAT_LATCH   =0x0004
+
+	REG_CONFIG_CQUE_MASK    =0x0003
+	REG_CONFIG_CQUE_1CONV   =0x0000
+	REG_CONFIG_CQUE_2CONV   =0x0001
+	REG_CONFIG_CQUE_4CONV   =0x0002
+	REG_CONFIG_CQUE_NONE    =0x0003
+	gains = OrderedDict([('GAIN_TWOTHIRDS',REG_CONFIG_PGA_6_144V),('GAIN_ONE',REG_CONFIG_PGA_4_096V),('GAIN_TWO',REG_CONFIG_PGA_2_048V),('GAIN_FOUR',REG_CONFIG_PGA_1_024V),('GAIN_EIGHT',REG_CONFIG_PGA_0_512V),('GAIN_SIXTEEN',REG_CONFIG_PGA_0_256V)])
+	gain_scaling =  OrderedDict([('GAIN_TWOTHIRDS',0.1875),('GAIN_ONE',0.125),('GAIN_TWO',0.0625),('GAIN_FOUR',0.03125),('GAIN_EIGHT',0.015625),('GAIN_SIXTEEN',0.0078125)])
+	type_selection = OrderedDict([('UNI_0',0),('UNI_1',1),('UNI_2',2),('UNI_3',3),('DIFF_01','01'),('DIFF_23','23')])
+	sdr_selection = OrderedDict([(8,REG_CONFIG_DR_8SPS),(16,REG_CONFIG_DR_16SPS),(32,REG_CONFIG_DR_32SPS),(64,REG_CONFIG_DR_64SPS),(128,REG_CONFIG_DR_128SPS),(250,REG_CONFIG_DR_250SPS),(475,REG_CONFIG_DR_475SPS),(860,REG_CONFIG_DR_860SPS)]) #sampling data rate
+
+	NUMPLOTS=1
+	PLOTNAMES = ['mV']
+	def __init__(self,I2C,**args):
+		self.ADDRESS = args.get('address',self.ADDRESS)		
+		self.I2C = I2C
+		self.channel = 'UNI_0'
+		self.gain = 'GAIN_ONE'
+		self.rate = 128
+
+		self.setGain('GAIN_ONE')
+		self.setChannel('UNI_0')
+		self.setDataRate(128)
+		self.conversionDelay = 8
+		self.name = 'ADS1115 16-bit ADC'
+		self.params={'setGain':self.gains.keys(),'setChannel':self.type_selection.keys(),'setDataRate':self.sdr_selection.keys()}
+		
+		
+
+		
+	def __readInt__(self,addr):
+		return int16(self.__readUInt__(addr))
+
+	def __readUInt__(self,addr):
+		vals = self.I2C.readBulk(self.ADDRESS,addr,2) 
+		v=1.*((vals[0]<<8)|vals[1])
+		return v
+
+	def initTemperature(self):
+		self.I2C.writeBulk(self.ADDRESS,[self.REG_CONTROL,self.CMD_TEMP])
+		time.sleep(0.005)
+
+	def readRegister(self,register):
+		vals =  self.I2C.readBulk(self.ADDRESS,register,2)
+		return (vals[0]<<8)|vals[1]
+
+	def writeRegister(self,reg,value):
+		self.I2C.writeBulk(self.ADDRESS,[reg,(value>>8)&0xFF,value&0xFF])
+
+	def setGain(self,gain):
+		'''
+		options : 'GAIN_TWOTHIRDS','GAIN_ONE','GAIN_TWO','GAIN_FOUR','GAIN_EIGHT','GAIN_SIXTEEN'
+		'''
+		self.gain = gain
+
+	def setChannel(self,channel):
+		'''
+		options 'UNI_0','UNI_1','UNI_2','UNI_3','DIFF_01','DIFF_23'
+		'''
+		self.channel = channel
+
+	def setDataRate(self,rate):
+		'''
+		data rate options 8,16,32,64,128,250,475,860 SPS
+		'''
+		self.rate = rate
+
+
+	def readADC_SingleEnded(self,chan):
+		if chan>3:return None
+		#start with default values
+		config = (self.REG_CONFIG_CQUE_NONE # Disable the comparator (default val)
+		|self.REG_CONFIG_CLAT_NONLAT        # Non-latching (default val)
+		|self.REG_CONFIG_CPOL_ACTVLOW 	    #Alert/Rdy active low   (default val)
+		|self.REG_CONFIG_CMODE_TRAD         # Traditional comparator (default val)
+		|self.sdr_selection[self.rate]         # 1600 samples per second (default)
+		|self.REG_CONFIG_MODE_SINGLE)        # Single-shot mode (default)
+
+		#Set PGA/voltage range
+		config |= self.gains[self.gain]
+
+		if chan == 0   : config |= self.REG_CONFIG_MUX_SINGLE_0
+		elif chan == 1 : config |= self.REG_CONFIG_MUX_SINGLE_1
+		elif chan == 2 : config |= self.REG_CONFIG_MUX_SINGLE_2
+		elif chan == 3 : config |= self.REG_CONFIG_MUX_SINGLE_3
+		#Set 'start single-conversion' bit
+		config |= self.REG_CONFIG_OS_SINGLE
+		self.writeRegister(self.REG_POINTER_CONFIG, config);
+		time.sleep(1./self.rate+.002) #convert to mS to S
+		return self.readRegister(self.REG_POINTER_CONVERT)*self.gain_scaling[self.gain]
+
+	def readADC_Differential(self,chan = '01'):
+		#start with default values
+		config = (self.REG_CONFIG_CQUE_NONE # Disable the comparator (default val)
+		|self.REG_CONFIG_CLAT_NONLAT        # Non-latching (default val)
+		|self.REG_CONFIG_CPOL_ACTVLOW 	    #Alert/Rdy active low   (default val)
+		|self.REG_CONFIG_CMODE_TRAD         # Traditional comparator (default val)
+		|self.sdr_selection[self.rate]         #  samples per second 
+		|self.REG_CONFIG_MODE_SINGLE)       # Single-shot mode (default)
+
+		#Set PGA/voltage range
+		config |= self.gains[self.gain]
+		if chan == '01':config |= self.REG_CONFIG_MUX_DIFF_0_1
+		elif chan == '23':config |= self.REG_CONFIG_MUX_DIFF_2_3
+		#Set 'start single-conversion' bit
+		config |= self.REG_CONFIG_OS_SINGLE
+		self.writeRegister(self.REG_POINTER_CONFIG, config);
+		time.sleep(1./self.rate+.002) #convert to mS to S
+		return int16(self.readRegister(self.REG_POINTER_CONVERT))*self.gain_scaling[self.gain]
+
+	def getLastResults(self):
+		return int16(self.readRegister(self.REG_POINTER_CONVERT))*self.gain_scaling[self.gain]
+
+	def getRaw(self):
+		'''
+		return values in mV
+		'''
+		chan = self.type_selection[self.channel]
+		if self.channel[:3]=='UNI':
+			return [self.readADC_SingleEnded(chan)]
+		elif self.channel[:3]=='DIF':
+			return [self.readADC_Differential(chan)]
+		
