After checking several libraries for ADS1115 usage (for maximally fast IC reading) i have stopped and chosen this tutorial (with native B4R code) and prepared an universal module.
- A 3rd MCU pin for interruption when the ADC measurement is finished (excepting 2 pins for I2C bus) is not used
- But delay for waiting the ADC result is used due to the MCU may hang and reboot sometimes if to read asynchronously as fast as needed
- I2C bus speed is set to 800000 bps for better performance (tests show that speed > 800 kbps does not help to read faster)
- Pre-checking that chip is really present on the declared I2C-bus address
- Reading all 4 channels, setup to max samples per second
- After reading - calculating the output values with scale factor of optional resistive divider and needed values range (example code is for measuring positive polarity voltage up to 4V DC)
Main module:
#Region Project Attributes
#AutoFlushLogs: True
#CheckArrayBounds: True
#StackBufferSize: 600
#End Region
Sub Process_Globals
Public Serial1 As Serial
End Sub
Private Sub AppStart
Serial1.Initialize(115200)
Log("AppStart")
esp_ads1115.Start_ads1115
End Sub
Module 'esp_ads1115':
'module esp_ads1115
'v.0.3
Private Sub Process_Globals
'These global variables will be declared once when the application starts.
'Public variables can be accessed from all modules.
'**********************************************
'ADC I2C
Private bc As ByteConverter
Private Wire As WireMaster
Private deviceaddress As Byte 'ignore, for inline-C
Private wireerror As Byte = 55 'ignore, for inline-C
Private ADC1115 As Byte = 0x48 'default i2c address
Private ADC_Address As Byte = ADC1115
Private const ADC_Channels As Byte = 4
Private Volt(ADC_Channels) As Double 'result voltages
Private Configs(ADC_Channels) As Int
Private Ranges(ADC_Channels) As Double
' 1111 0100 0010 0011 'legend
' | | | ||| |||| - 0011=comparator is disabled
' | | | 000 8 SPS
' | | | 001 16 SPS
' | | | 010 32 SPS
' | | | ....
' | | | 100 128 SPS (default)
' | | | ....
' | | | 111 860 SPS
' | | |
' | | Mode 0=cont. conversion 1=Single-shot
' | |
' | 000 6.144V
' | 001 4.096V - used this
' | 010 2.048V (DEFAULT)
' | 011 1.024V
' | 100 0.512V
' | 11x 0.256V
' 000 = AINp=AIN0 And AINn=AIN1 (default)
' 001 = AINp=AIN0 And AINn=AIN3
' 010 = AINp=AIN1 And AINn=AIN3
' 011 = AINp=AIN2 And AINn=AIN3
' 100 = AINp=AIN0 And AINn=GND - used these 4 single polarity
' 101 = AINp=AIN1 And AINn=GND
' 110 = AINp=AIN2 And AINn=GND
' 111 = AINp=AIN3 And AINn=GND
Private ADCChannel As Byte
'**********************************************
Private Timer1 As Timer
Dim Ready_flag As Boolean
Private ResistorDividers(ADC_Channels) As Double
Private MinValues(ADC_Channels) As Double
Private MaxValues(ADC_Channels) As Double
Public Values(ADC_Channels) As Double 'result measurements
End Sub
Sub Start_ads1115
'********************************************************
Configs(0) = 0xC2E3 '1100 0010 1110 0011 +AN0 -GND 4,096 V
Ranges(0) = 4.096
Configs(1) = 0xD2E3 '1101 0010 1110 0011 +AN1 -GND 4,096 V
Ranges(1) = 4.096
Configs(2) = 0xE2E3 '1110 0010 1110 0011 +AN2 -GND 4,096 V
Ranges(2) = 4.096
Configs(3) = 0xF2E3 '1111 0010 1110 0011 +AN3 -GND 4,096 V
Ranges(3) = 4.096
ResistorDividers(0) = 1 '390 / 270 'kOhm, Rout / Rin
ResistorDividers(1) = 1
ResistorDividers(2) = 1
ResistorDividers(3) = 1
MinValues(0) = 0 'needed output converted (measured) value range, low limit, channel 0
MaxValues(0) = 100 'needed output converted (measured) value range, high limit, channel 0
MinValues(1) = 0 'needed output converted (measured) value range, low limit, channel 1
MaxValues(1) = 100 'needed output converted (measured) value range, high limit, channel 1
MinValues(2) = 0 'needed output converted (measured) value range, low limit, channel 2
MaxValues(2) = 100 'needed output converted (measured) value range, high limit, channel 2
MinValues(3) = 0 'needed output converted (measured) value range, low limit, channel 3
MaxValues(3) = 100 'needed output converted (measured) value range, high limit, channel 3
Wire.Initialize
Log("Start reading ads1115...")
Ready_flag = False
'-------test if device presents-----
deviceaddress = ADC1115
RunNative("SetWireClock", 800000)
RunNative("icwirebegintransmisson", Null)
RunNative("icwireendtransmisson", Null)
Dim b(1) As Byte
b(0) = ADC1115
If wireerror = 0 Then
Log("ADC1115 I2C device found at address: 0x", bc.HexFromBytes(b), " (", ADC1115, ")")
Else
Log("ADC1115 device was not found at 0x", bc.HexFromBytes(b), " (", ADC1115, ")")
Return
End If
'----------------------------
Set_ADC (Configs(0))
ADCChannel = 0
ADC_Address = ADC1115
Timer1.Initialize("Timer1_Tick", 20) '20 = OK
Timer1.Enabled = True
End Sub
Sub Stop
Timer1.Enabled = False
Log("esp_ads1115 stopped")
End Sub
Private Sub Timer1_Tick
Dim ADCV As Int = ADC_SS_read(Configs(ADCChannel))
Volt(ADCChannel) = Convert_2_Volt(ADCV, Ranges(ADCChannel)) / ResistorDividers(ADCChannel)
Values(ADCChannel) = doubleMap(Volt(ADCChannel), 0, Ranges(ADCChannel), MinValues(ADCChannel), MaxValues(ADCChannel))
Log("Volt(", ADCChannel, ") = ", Volt(ADCChannel), "; ", Values(ADCChannel))
ADCChannel = ADCChannel + 1
If ADCChannel = ADC_Channels Then
Ready_flag = True
ADCChannel = 0
End If
End Sub
'Config ADC
Private Sub Set_ADC (Config As Int)
'Set config register 0x1
Wire.WriteTo(ADC_Address, Array As Byte(0x1, Bit.HighByte(Config), Bit.LowByte(Config)))
'Select ADC conversion register 0x0
' 0x0 = conversion register
' |
' v
Wire.WriteTo(ADC_Address, Array As Byte(0x0))
End Sub
'Read ADC single shot, return ADC value Int
Private Sub ADC_SS_read (Config As Int) As Int
'Set config register 0x1
Config = Bit.Or(Config, 0x0100)
'ADC config and start conversion
Set_ADC(Config)
'get Samples per Seconds setting
Dim SPS As UInt = Bit.ShiftRight(Bit.And(Bit.LowByte(Config), 0xE0),5)
'conversion time from 125 to 1,16 mS (8 to 860 SPS)
Dim Mdelay As UInt
Select SPS
Case 0 '8
Mdelay = 1000000 / 8
Case 1 '16
Mdelay = 1000000 / 16
Case 2 '32
Mdelay = 1000000 / 32
Case 3 '64
Mdelay = 1000000 / 64
Case 4 '128
Mdelay = 1000000 / 128
Case 5 '250
Mdelay = 1000000 / 250
Case 6 '475
Mdelay = 1000000 / 475
Case 7 '860
Mdelay = 1000000 / 860
End Select
DelayMicroseconds(Mdelay) 'wait for conversion
'read ADC
Return Read_ADC2
End Sub
'Read ADC return array High - Low
Private Sub Read_ADC () As Byte()
Return Wire.RequestFrom(ADC_Address, 2) 'High - Low
End Sub
'Read ADC return Int number
Private Sub Read_ADC2 () As Int
Dim data() As Byte = Read_ADC
Return Bit.Shiftleft(data(0),8) + data(1) 'Convert array to Int and return it
End Sub
'Convert ADC number to Volt
Private Sub Convert_2_Volt (ADC_Value As Int, Range As Float) As Float
Return (ADC_Value * Range / 32767)
End Sub
'Read ADC return Vols
Private Sub Read_Volt (Range As Float) As Float
Dim data() As Byte = Read_ADC 'alternate reading
Return (Bit.Shiftleft(data(0),8) + data(1)) * Range / 32767
End Sub
Public Sub doubleMap(analoginputvalue As Double,in_min As Double,in_max As Double,out_min As Double,out_max As Double) As Double
Dim a As Double = (analoginputvalue - in_min) * (out_max - out_min) / (in_max - in_min) + out_min
Return a
End Sub
#if C
#include <Wire.h>
void icwirebegintransmisson (B4R::Object* o) {
Wire.beginTransmission(b4r_esp_ads1115::_deviceaddress);
}
void icwireendtransmisson (B4R::Object* o) {
b4r_esp_ads1115::_wireerror = Wire.endTransmission();
}
void SetWireClock(B4R::Object* o) {
Wire.setClock (o->toULong());
}
#End if
Module 'esp_ads1115':
'module esp_ads1115
'v.0.2
Private Sub Process_Globals
'These global variables will be declared once when the application starts.
'Public variables can be accessed from all modules.
'**********************************************
'ADC I2C
Private bc As ByteConverter
Private Wire As WireMaster
Private deviceaddress As Byte 'ignore, for inline-C
Private wireerror As Byte = 55 'ignore, for inline-C
Private ADC1115 As Byte = 0x48 'default i2c address
Private ADC_Address As Byte = ADC1115
Private ADC_Channel As Byte = 4
Private Volt(ADC_Channel) As Double 'result voltages
' 1100 0010 1110 0011 '+AN0 -GND 4,096 V
Private Config0 As Int = 0xC2E3 '+AN0 -GND 4,096 V
Private Range0 As Float = 4.096
' 1101 0010 1110 0011 '+AN1 -GND 4,096 V
Private Config1 As Int = 0xD2E3 '+AN1 -GND 4,096 V
Private Range1 As Float = 4.096
' 1110 0010 1110 0011 '+AN2 -GND 4,096 V
Private Config2 As Int = 0xE2E3 '+AN2 -GND 4,096 V
Private Range2 As Float = 4.096
' 1111 0010 1110 0011 '+AN3 -GND 4,096 V
Private Config3 As Int = 0xF2E3 '+AN3 -GND 4,096 V
Private Range3 As Float = 4.096
'
' 1111 0100 0010 0011 'legend
' | | | ||| |||| - 0011=comparator is disabled
' | | | 000 8 SPS
' | | | 001 16 SPS
' | | | 010 32 SPS
' | | | ....
' | | | 100 128 SPS (default)
' | | | ....
' | | | 111 860 SPS
' | | |
' | | Mode 0=cont. conversion 1=Single-shot
' | |
' | 000 6.144V
' | 001 4.096V - used this
' | 010 2.048V (DEFAULT)
' | 011 1.024V
' | 100 0.512V
' | 11x 0.256V
' 000 = AINp=AIN0 And AINn=AIN1 (default)
' 001 = AINp=AIN0 And AINn=AIN3
' 010 = AINp=AIN1 And AINn=AIN3
' 011 = AINp=AIN2 And AINn=AIN3
' 100 = AINp=AIN0 And AINn=GND - used these 4 single polarity
' 101 = AINp=AIN1 And AINn=GND
' 110 = AINp=AIN2 And AINn=GND
' 111 = AINp=AIN3 And AINn=GND
Private ADCChannel As Byte
'**********************************************
Private Timer1 As Timer
Dim Ready_flag As Boolean
Private ResistorDivider0 As Double = 1 '390 / 270 'kOhm, Rout / Rin
Private ResistorDivider1 As Double = 1
Private ResistorDivider2 As Double = 1
Private ResistorDivider3 As Double = 1
Private MinValue0 As Double = 0 'needed output converted (measured) value range, low limit, channel 0
Private MaxValue0 As Double = 100 'needed output converted (measured) value range, high limit, channel 0
Private MinValue1 As Double = 0
Private MaxValue1 As Double = 100
Private MinValue2 As Double = 0
Private MaxValue2 As Double = 100
Private MinValue3 As Double = 0
Private MaxValue3 As Double = 100
Public Values(ADC_Channel) As Double 'result measurements
End Sub
Sub Start_ads1115
'********************************************************
'ADC I2C
'Data on Lolin32 - ESP32
'96,15kHz , 10,4uS clock
'config = 9+9+9+9 = 36x10 = 375uS about
'sel conf reg. = 9+9 = 18x10= 187uS about
'read conv. = 9+9+9 = 27x10= 280uS about
'read-set-next = 280+375+187 = 842 uS about
Wire.Initialize
Log("Start reading ads1115...")
Ready_flag = False
'-------test if device presents-----
deviceaddress = ADC1115
RunNative("SetWireClock", 800000)
RunNative("icwirebegintransmisson", Null)
RunNative("icwireendtransmisson", Null)
Dim b(1) As Byte
b(0) = ADC1115
If wireerror = 0 Then
Log("ADC1115 I2C device found at address: 0x", bc.HexFromBytes(b), " (", ADC1115, ")")
Else
Log("ADC1115 device was not found at 0x", bc.HexFromBytes(b), " (", ADC1115, ")")
Return
End If
'----------------------------
Set_ADC (Config0)
ADCChannel = 0
ADC_Address = ADC1115
Timer1.Initialize("Timer1_Tick", 20) '20 = OK
Timer1.Enabled = True
End Sub
Sub Stop
Timer1.Enabled = False
Log("esp_ads1115 stopped")
End Sub
Private Sub Timer1_Tick
Select ADCChannel
Case 0
Dim ADCV As Int = ADC_SS_read(Config0)
Volt(0) = Convert_2_Volt (ADCV, Range0) / ResistorDivider0
Values(0) = CalcValue
Log("Volt(0) = ", Volt(0), "; ", Values(0))
ADCChannel = 1
Case 1
Dim ADCV As Int = ADC_SS_read(Config1)
Volt(1) = Convert_2_Volt (ADCV, Range1) / ResistorDivider1
Values(1) = CalcValue
Log("Volt(1) = ", Volt(1), "; ", Values(1))
ADCChannel = 2
Case 2
Dim ADCV As Int = ADC_SS_read(Config2)
Volt(2) = Convert_2_Volt (ADCV, Range2) / ResistorDivider2
Values(2) = CalcValue
Log("Volt(2) = ", Volt(2), "; ", Values(2))
ADCChannel = 3
Case 3
Dim ADCV As Int = ADC_SS_read(Config3)
Volt(3) = Convert_2_Volt (ADCV, Range3) / ResistorDivider3
Values(3) = CalcValue
Log("Volt(3) = ", Volt(3), "; ", Values(3))
ADCChannel = 0
Ready_flag = True
End Select
End Sub
Private Sub CalcValue As Double
Dim a As Double
Select ADCChannel
Case 0
a = doubleMap(Volt(0), 0, Range0, MinValue0, MaxValue0)
Case 1
a = doubleMap(Volt(1), 0, Range1, MinValue1, MaxValue1)
Case 2
a = doubleMap(Volt(2), 0, Range2, MinValue2, MaxValue2)
Case 3
a = doubleMap(Volt(3), 0, Range3, MinValue3, MaxValue3)
End Select
Return a
End Sub
'Config ADC
Private Sub Set_ADC (Config As Int)
'Set config register 0x1
Wire.WriteTo(ADC_Address, Array As Byte(0x1, Bit.HighByte(Config), Bit.LowByte(Config)))
'Select ADC conversion register 0x0
' 0x0 = conversion register
' |
' v
Wire.WriteTo(ADC_Address, Array As Byte(0x0))
End Sub
'Read ADC single shot, return ADC value Int
Private Sub ADC_SS_read (Config As Int) As Int
Dim Mdelay As UInt
'Set config register 0x1
Config = Bit.Or (Config,0x0100)
'ADC config and start conversion
Wire.WriteTo(ADC_Address, Array As Byte(0x1, Bit.HighByte(Config), Bit.LowByte(Config))) '36clk -> 370uS
'select conversion register for read
Wire.WriteTo(ADC_Address, Array As Byte(0x0)) '18clk = 187 uS
'get Samples per Seconds setting
Dim SPS As UInt = Bit.ShiftRight(Bit.And(Bit.LowByte(Config), 0xE0),5)
'conversion time from 125 to 1,16 mS (8 to 860 SPS)
Select SPS
Case 0 '8
Mdelay = 1000000 / 8
Case 1 '16
Mdelay = 1000000 / 16
Case 2 '32
Mdelay = 1000000 / 32
Case 3 '64
Mdelay = 1000000 / 64
Case 4 '128
Mdelay = 1000000 / 128
Case 5 '250
Mdelay = 1000000 / 250
Case 6 '475
Mdelay = 1000000 / 475
Case 7 '860
Mdelay = 1000000 / 860
End Select
DelayMicroseconds(Mdelay) 'wait for conversion
'read ADC
Dim data() As Byte = Wire.RequestFrom(ADC_Address, 2)
Return Bit.Shiftleft(data(0),8) + data(1) 'Covert array to Int and return it
End Sub
'Read ADC return array High - Low
Private Sub Read_ADC () As Byte()
Return Wire.RequestFrom(ADC_Address, 2) 'High - Low
End Sub
'Read ADC return Int number
Private Sub Read_ADC2 () As Int
Dim data() As Byte = Wire.RequestFrom(ADC_Address, 2)
Return Bit.Shiftleft(data(0),8) + data(1)
End Sub
'Convert ADC number to Volt
Private Sub Convert_2_Volt (ADC_Value As Int, Range As Float) As Float
Return (ADC_Value * Range / 32767)
End Sub
'Read ADC return Vols
Private Sub Read_Volt (Range As Float) As Float
Dim data() As Byte = Read_ADC 'alternate reading
Return (Bit.Shiftleft(data(0),8) + data(1)) * Range / 32767
End Sub
Public Sub doubleMap(analoginputvalue As Double,in_min As Double,in_max As Double,out_min As Double,out_max As Double) As Double
Dim a As Double = (analoginputvalue - in_min) * (out_max - out_min) / (in_max - in_min) + out_min
Return a
End Sub
#if C
#include <Wire.h>
void icwirebegintransmisson (B4R::Object* o) {
Wire.beginTransmission(b4r_esp_ads1115::_deviceaddress);
}
void icwireendtransmisson (B4R::Object* o) {
b4r_esp_ads1115::_wireerror = Wire.endTransmission();
}
void SetWireClock(B4R::Object* o) {
Wire.setClock (o->toULong());
}
#End ifAttachments
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