Arduino MKR WIFI 1010 Start

Program

Copy the following code into a new sketch.


/*
  Target board Arduino MKR WIFI 1010
  This sketch generates a sine signal with 
     DAC: DAC0, AIN[0], PA02, A0, D15
     PWL: AIN[7],PA07,A6,D21
     Digital: PA22,23,10,11,PB10,11,PA20, PA21
  This sketch samples:
    OSC1: AIN[10], PB02, A1, D16 
    OSC2: AIN[11], PB03, A2, D17
    OSC3: AIN[4], PA04, A3, D18 
    OSC4: AIN[5], PA05, A4, D19  
  Transfers 1024 values to serial port.
    
  Setup:  
  Array of sine values is generated.

  Loop:
  4 times
    1024 times
      Set sine DAC, PWL, Digital
      Read OSC1..4 to array
  Transfer last 1024 values to serial port.
  
  This example code is in the public domain.

  Written 9 Sep 2020 by Joerg Vollrath
*/

#define DAC          A0

#define DAC_D0          0
#define DAC_D1          1
#define DAC_D2          2
#define DAC_D3          3
#define DAC_D4          4
#define DAC_D5          5
#define DAC_D6          6
#define DAC_D7          13

#define DAC_PWM          8

#define ADC_OSC1          A1
#define ADC_OSC2          A2
#define ADC_OSC3          A3
#define ADC_OSC4          A4

// Sine wave lookup table 0..255 Sinbe.xlsx
uint16_t sineWave[] = { 
    128,131,134,137,140,143,146,149,152,155,158,162,165,167,170,173,
    176,179,182,185,188,190,193,196,198,201,203,206,208,211,213,215,
    218,220,222,224,226,228,230,232,234,235,237,238,240,241,243,244,
    245,246,248,249,250,250,251,252,253,253,254,254,254,255,255,255,
    255,255,255,255,254,254,254,253,253,252,251,250,250,249,248,246,
    245,244,243,241,240,238,237,235,234,232,230,228,226,224,222,220,
    218,215,213,211,208,206,203,201,198,196,193,190,188,185,182,179,
    176,173,170,167,165,162,158,155,152,149,146,143,140,137,134,131,  
    128,124,121,118,115,112,109,106,103,100,97,93,90,88,85,82,
    79,76,73,70,67,65,62,59,57,54,52,49,47,44,42,40,
    37,35,33,31,29,27,25,23,21,20,18,17,15,14,12,11,
    10,9,7,6,5,5,4,3,2,2,1,1,1,0,0,0,
    0,0,0,0,1,1,1,2,2,3,4,5,5,6,7,9,
    10,11,12,14,15,17,18,20,21,23,25,27,29,31,33,35,
    37,40,42,44,47,49,52,54,57,59,62,65,67,70,73,76,
    79,82,85,88,90,93,97,100,103,106,109,112,115,118,121,124
};
// Buffer for ADC values of 4 channels
    uint16_t osc1[] = {
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
    };
    uint16_t osc2[] ={
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
      };
    uint16_t osc3[] = {
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
      };
    uint16_t osc4[] = {
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
      0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
    };
    uint16_t bitsX[] = {1,2,4,8,16,32,64,128};
    

void setup() {
  // put your setup code here, to run once:
  pinMode(DAC_D0, OUTPUT);
  pinMode(DAC_D1, OUTPUT);
  pinMode(DAC_D2, OUTPUT);
  pinMode(DAC_D3, OUTPUT);
  pinMode(DAC_D4, OUTPUT);
  pinMode(DAC_D5, OUTPUT);
  pinMode(DAC_D6, OUTPUT);
  pinMode(DAC_D7, OUTPUT);
 
 // initialize serial communication at 115200
 Serial.begin(115200);
 Serial.println("\r\nData Converter Sine Test");

}

// Setting 8 digital outputs for R2R DAC
void digWrite(uint16_t sineValue){
// It takes some time (20us?) to set all pins
// Settling tim emeasurements will be skewed
  if ((sineValue & bitsX[0]) == bitsX[0] ) {
    digitalWrite(DAC_D0, HIGH);
  } else {
    digitalWrite(DAC_D0, LOW);    
  }
  if ((sineValue & bitsX[1]) == bitsX[1] ) {
    digitalWrite(DAC_D1, HIGH);
  } else {
    digitalWrite(DAC_D1, LOW);    
  }
  if ((sineValue & bitsX[2]) == bitsX[2] ) {
    digitalWrite(DAC_D2, HIGH);
  } else {
    digitalWrite(DAC_D2, LOW);    
  }
  if ((sineValue & bitsX[3]) == bitsX[3] ) {
    digitalWrite(DAC_D3, HIGH);
  } else {
    digitalWrite(DAC_D3, LOW);    
  }
  if ((sineValue & bitsX[4]) == bitsX[4] ) {
    digitalWrite(DAC_D4, HIGH);
  } else {
    digitalWrite(DAC_D4, LOW);    
  }
  if ((sineValue & bitsX[5]) == bitsX[5] ) {
    digitalWrite(DAC_D5, HIGH);
  } else {
    digitalWrite(DAC_D5, LOW);    
  }
  if ((sineValue & bitsX[6]) == bitsX[6] ) {
    digitalWrite(DAC_D6, HIGH);
  } else {
    digitalWrite(DAC_D6, LOW);    
  }
  if ((sineValue & bitsX[7]) == bitsX[7] ) {
    digitalWrite(DAC_D7, HIGH);
  } else {
    digitalWrite(DAC_D7, LOW);    
  }
  
}

void loop() {
  // put your main code here, to run repeatedly:

    // 4 periods
    for (int i2 = 0; i2 < 4; i2++) {
	  // 256 samples written and read
      for (int i1 = 0; i1 < 256; i1++) {
        // writing Analog
        analogWrite(DAC, sineWave[i1]);
        // writing PWM
        analogWrite(DAC_PWM, sineWave[i1]);
        // writing digital
        digWrite(sineWave[i1]);       
        // reading analog
        osc1[i1] = analogRead(ADC_OSC1);
        osc2[i1] = analogRead(ADC_OSC2);
        osc3[i1] = analogRead(ADC_OSC3);
        osc4[i1] = analogRead(ADC_OSC4);
      }
    }

    // transfer data to PC via serial interface
    Serial.println("New block: ");
    for (int i3 = 0; i3 < 256; i3++) {
      Serial.print(i3);
      Serial.print(" , Sine = ");
      Serial.print(sineWave[i3]);
      Serial.print(" , ADC(OSC1) = ");
      Serial.print(osc1[i3]);
      Serial.print(" , ADC(OSC2) = ");
      Serial.print(osc2[i3]);
      Serial.print(" , ADC(OSC3) = ");
      Serial.print(osc3[i3]);
      Serial.print(" , ADC(OSC4) = ");
      Serial.println(osc4[i3]);
    }
     
    delay(10);

}

Wire connections for test

The Electronic Explorer is used for measurements.
The basic operation of the Electronic Explorer is shown here.

Connect PWM output to oscilloscope channel 2.
Connect ADC 1,2,3,4 to DAC output.
Connect DAC output to oscilloscope 1.
Connect one digital pin to oscilloscope 3.

Sampling data from the ADC with DAC sine/ramp input allows data converter investigations for INL, DNL and SNR.
The measuring device should have a higher resolution than the device under test (DUT).
A high resolution DAC can generate a test signal for a ADC investigation.
A high resolution ADC can sample the output of the DAC investigation.

Connect the USB cable of the MKR WIFI 1010.
Start the Arduino IDE from: L:\apps\Arduino\Arduino.exe
Start COM tool IDE from: L:\apps\Arduino\Com Port
Select correct board: Werkzeuge (Tools) -> Board -> Board management
ARDUINO SAMD(32-bit Arm Cortex - M0+) Boards, Install
Arduino MKR WIFI 1010
Select correct COM port: Werkzeuge (Tools) -> Port
Compile and upload sketch: Sketch -> Hochladen (Upload)
Open serial monitor: Werkzeuge (Tools) -> Serieller Monitor (Serial monitor)
You should see generated values and readout of ADCs.

Data logging

Option 1:
Use serial monitor
Disable Autoscroll
Select data with mouse
Copy data with <STRG><C> or <CTRL><C>
Paste data with <STRG><V> or <CTRL><V>
Use serial plotter for graphical ouptut to check waveform

Option 2:
Close serial monitor.
For data logging open Hyperterminal: L.\apps\Hyperterminal\hypertrm.exe
Select COM port.
Put in baud rate 115200.
Start logging data: Übertragung -> Text aufzeichnen
Select a path and file name (Durchsuchen) and start logging (Starten).
After gathering needed data do stop logging (Beenden)

You can analyze the logged data at home with Excel or the FFT tool.

Electronic Explorer as Waveform Generator and Oscilloscope

The Electronic Explorer is used for measurements.
The basic operation of the Electronic Explorer is shown here.

Connect the DAC outputs to the Electronic Explorer SCOPE 1 DC and SCOPE 2 DC channels.
Start Waveforms on the Desktop to be able to look at the waveforms using and oscilloscope.
Start SCOPE from the control center.
Enable channel 1 and 2.
Select under time Range 200 ms.
Move the curves to the center of the window.
Adjust amplitude and Offset for channel 1 and 2.
You can export data for further analysis.

Challenges

It was difficult to determine the names of the pins.
Bit conversion to digital pins is sensitive to type.
Disconnect Arduino IDE serial monitor.
Start Hyperterm with 115200 to log data.
Sine lookup and logged data (SineFirst.TXT) Sine.xlsx
Data log file

Offset, Gain Error and LSB

Apply 0V to the ADC inputs.
The minimum value of the ADC(OSC1) is 5.
Attention don't damage the ADC inputs with a high voltage (Vin > 1 V/3.3V/5V).
Look in the data sheet for the maximum allowed input voltage.
Apply maximum possible ADC input voltage to the ADC inputs.
The maximum value of the ADC(OSC1) is 1021.

Compare minimum and maximum of the four ADC channels.
What is DAC Error and what is ADC error?
Calculate LSB?

The oscilloscope shows the following waveforms.

The short break after 4 periods for sending serial data can be seen.
C1 (orange) shows the analog sine output.
C2 (blue) shows the pulse width modulated output.
C3 (red) shows D5 digital output of bit 5.
Minimum of sine signal is 30mV, maximum 3.31 V with a frequency of 1.13 Hz and period of 880 ms.
In this configuration sampling is done with 289.28 Hz and 3.48 ms.

A FFT can be done: FFT Tool .
This can be based on oscilloscope data or logged data via the serial interface.

Due to changing slope of sine signal there are 140 missing codes.
Signal level for frequency 1 (one period) 36.09dB and total noise -13.26 dB.
Highest harmonic for frequency 47 at -22.81 dB.
SNR = (36.09 - (-13.26)) dB = 49.35 dB
ENOB = (SNR - 1.76 dB) / 6.02 dB = 8 Bit

Now scaling to 10 bits in FFT tool is done. This can be seen at the range of the displayed sine signal.

899 Missing codes.
Signal level for frequency 1 (one period) 48.11dB and total noise 3.1 dB.
Highest harmonic for frequency 2 at -8.44 dB.
SNR = (48.11 - 3.1) dB = 45.01 dB
ENOB = (SNR - 1.76 dB) / 6.02 dB = 7.5 Bit

Part list

Part	Number	Cost (Euro)
Arduino MKR WIFI 1010	1	30.-
Digilent PMOD AD2	1	20.-
Digilent PMOD DA2	1	20.-
Resistor 20k	8 (0)
Resistor 10k	7 (23)
Jumper wire (Drähte)	32
Micro USB cable	1

Pin Assignments

Built in DAC: A0
PWM DAC: D7
External DAC PMOD DA2 with SPI interface: CS A6, SCK D9, MOSI D8
8-bit digital signals for DAC: D0,D1,D2,D3,D4,D5,D6,D13
4 ADC as Oscilloscope: OSC1..4, A1..A4
External ADC PMOD AD2 with I2C interface: SDA D11, SCL D12

R2R DAC

Build the R2R DAC on the board. Connect the output to OSC4, A4 and OSC2, A2, .

Pin Arduino	Name	Name	R2R
D0	D0	D0	D0
D1	D1	D1	D1
D2	D2	D2	D2
D3	D3	D3	D3
D4	D4	D4	D4
D5	D5	D5	D5
D6	D6	D6	D6
D13	D13	D7	D7
A4	OSC4	Output R2R	Output R2R

R2R DAC First test

Connect DAC and OSC1 pin on Arduino.
The sine signal from DAC is sampled with OSC1.

Connect the USB cable of the MKR WIFI 1010.
Start the Arduino IDE from: L:\apps\Arduino\Arduino.exe
Start COM tool IDE from: L:\apps\Arduino\Com Port
Select correct board: Werkzeuge (Tools) -> Board
Select correct COM port: Werkzeuge (Tools) -> Port
Compile and upload sketch: Sketch -> Upload
Open serial monitor: Werkzeuge (Tools) -> Serial monitor
You should see generated values and readout of ADCs.

Option 1:
Use serial monitor
Disable Autoscroll
Select data with mouse
Copy data with <STRG><C> or <CTRL><C>
Paste data with <STRG><V> or <CTRL><V>
Use serial plotter for graphical ouptut to check waveform

Option 2:
Close serial monitor.
For data logging open Hyperterminal: L.\apps\Hyperterminal\hypertrm.exe
Select COM port.
Put in baud rate 115200.
Start logging data: Übertragung -> Text aufzeichnen
Select a path and file name (Durchsuchen) and start logging (Starten).
After gathering needed data do stop logging (Beenden)

You can analyze the logged data at home with Excel or the FFT tool.

PMOD DA2 ( 2 Channel, 12-Bit, 125kHz, 8 µs)

Connect DA2 to the Arduino.

Pin Arduino	Name	Name	Pin PMOD DA2
D9	SCK	CLK	4
D8	MOSI	D1	2
D21	D21	CS	1
GND	GND	GND	5
+3V3	VCC	VDD	6

Only Output Vout1 is used for signal generation.

Digilent: PMOD DA2 20.-
Texas Instruments DAC121S101 8us settling 12-Bit 16.5 MS/s $1.-

30 MHz SCLK

PMOD AD2

Connect AD2 to the Arduino.

Pin Arduino	Name	Name	Pin PMOD AD2
D12	SCL	SCL	1
D11	SDA	SDA	2
GND	GND	GND	3
+3V3	VCC	VDD	4

Only Input V1 is used for data acquisition.

Digilent: PMOD AD2 20.-
Analog devices AD7991 4 channel, I2C, 1us conversion time, 12-bit

Arduino sketch:

There is a new sketch available: DataConverterCharV2.ino
There is no ADC data buffer used in the program any more, since the memory size of variables is limited to 32kByte.
ADC readings are directly transfered via serial interface. This gives a sampling rate of 233 Samples/s.
Column sequence of output is different: index, ramp/sine value, ADC(AD2), ADC(Osc1), ADC(Osc2), ADC(Osc3), ADC(Osc4)
16k data blocks are generated for ramp or sine analysis usable for 12 bit data converters.

This outputs waveform from PMOD DA2 at Vout1 and reads V1 from the PMOD AD2.
Connect Output PMOD DA2 to oscilloscope channel 4.
Inside of the program the variable freq sets the waveform.

variable freq	100	300	500	700	900
Output	Ramp	1 sine	11 sine	101 sine	1001 sine

The variable oscConfig changes the number of simultaneous measurements and output columns. This can speed up acquisition.

variable oscConfig	1	2	3	4
Output	AD2,OSC1,OSC2,OSC3,OSC4	AD2,OSC1	AD2	OSC1

This configuration makes it possible to connect any DAC to any ADC to study system behaviour, INL, DNL and SNR.
A given sine signal code is fed to DAC and sampled with ADC giving an integer output code at the serial interface for further analysis.

What is the maximum sampling frequency?
How does the signal and FFT look at higher frequencies?
Is there any jitter present?

Tasks

(1) Task: PMOD ADC log data min, max, FFT, 1 Period, more periods,
Compare channel 1, 2, 3, 4, FFT SNR
(2) Task: Ramp test 0..255
Calculate INL, DNL

Data processing

Data can be copied from serial monitor disabling Autoscroll.
Selecting all data with <Strg><a>.
Copying selected data with <Strg><c>.
Inserting data into Excel via Start, Insert, Textconversion, delimited, Delimiter: comma, "=".
Data can be then selected and copied for FFT to Javascript FFT tool .
For ramp data another column in Excel is generated using verketten, concatenate (concatenate(A2,";",C2))to generate lines like: 23;56
.

Time (s);C2 (V)
0;0
1;0
2;0
..

DAC ramp data can then be copied and analyzed with Javascript read oscilloscope data tool .

Questions

What is the SNR for the digital sine data?
What is the SNR for Arduino DAC measured with PMOD AD2 and Arduino ADC?
What is the SNR for R2R DAC measured with PMOD AD2 and Arduino ADC?
What is the difference in SNR using windowing?
What is the INL, DNL for a ramp test of R2R, Arduino DAC, PMOD DAC measured with PMOD ADC and Arduino ADC?
3 measurement setups with 2 output data each.
Do a histogram test of Arduino ADC with PMOD DA2 as signal generator.

There is a browser based experimental application available for controlling the Arduino MKRWIFI1010 for DAC analysis.

AWG1: Ideal digital data fed to PMOD DA2 and DAC0/A0 Arduino pin

C1: PMOD ADC

C2: Arduino pin A1

C3: Arduino pin A2

C4: Arduino pin A3

A NodeEEBench_V07.zip file containing nodejs with npm and the HTML and webserver files can be downloaded.
Copy the files into C:\temp. All files should then be in the directory C:\temp\NodeEEBench.
The Arduino needs the sketch: DataConverterCharV4.ino in the directory C:\temp\NodeEEBench\Arduino\DataConverterCharV4.
After downloading the sketch to the Arduino find the COM Port associated with the Arduino board.
Edit line 47 of C:\temp\NodeEEBench\ServerA.js and insert correct COM port.
An Internetapplication can than be started by clicking on:
C:\temp\NodeEEBench\StartServerAx.bat

A command window will open starting a internet page. Then the browser should open the internet address http://localhost:3000
with the application to control the Arduino board.
At the end of your session please stop the nodejs server with a <STRG>C keyboard entry.

Operation

Waveform Selection

Select a waveform in the waveform generator AWG tab and start the generator 'Run'.
You can see the feed back about the waveform at the configuration tab under the sent command section.

Waveform Acquisition

Change to the oscilloscope tab and click 'Run'. Data is gathered. The Arduino is very slow and therefore data is slowly gathered and the graph is updated.
Below the graph the running number shows the acquisition process.
Each waveform can be activated or deactivated.
Data can be extracted clicking on the Save button in the oscilloscope tab, selecting the data and copying them to a text file or into a spreadsheet program.
This data is taken when you click on the button and not updated until again clicking on the button.
The hide button removes the data list.

If the sine waveform is activated a FFT is generated after acquisition of 16k data.
If the triangle waveform is activated a INL, DNL plot is generated after acquisition of 4k data.

FFT tab

Pressing the run button activates FFT display. All selected waveforms in the oscilloscope window are plotted.
Only FFT of a sine signal makes sense for ADC, DAC Analysis.
A table with signal magnitude and total noise magnitude can be activated by selecting a "Channel".
The number of considered points can be reduced py a power of 2.
Take screenshots for documentation.

Ramp Test INL, DNL tab

By selecting Calculate for Channel and update of the data is initiated.
By default 256 codes in the range of 0 to 255 with step size 1 is considered.
Calculating a best case lookup table can be activated.

Lookup Table

A lookup table can be downloaded to the Arduino.
It has 256 comma separated values in the range from 0..255.
All generated waveform codes will use the lookup table to get a real code for the 8 bit DAC.
The button reset table resets the table to default state without lookup.
Here you can explore different error correction schemes.
Having less codes gives a smaller range and sine wave generator and Ramp Tes range have to be adjusted.

Further Instructions

Please give feedback about the operation of the program.
What is missing in the instructions?
Is anything not working?
Are the calculations correct?
What features are missing?
Please assess severity of these issues.
Are there any benefits or good features of this application?
Do you like this application?

DAC Characterization

Ramp measurement for INL, DNL
Settling time with full scale and midscale
Sine signal FFT SNR

Use ADCs (serial port) and Electronic Explorer oscilloscope input (Export data) for acquiring signals

ADC Characterization

Ramp measurement histogram for INL, DNL
Sine signal FFT SNR

Generate ramp with Electronic Explorer AWG1 or PMOD DAC
Use ADCs (serial port) and Electronic Explorer oscilloscope input (Export data) for acquiring signals

DAC characterization

Use 12-bit PMOD ADC for measurement acquisition.

Arduino DAC: measure ramp and calculate INL, DNL
Arduino DAC: measure sine, do FFT and calculate SNR for 2 frequencies
R2R DAC: measure ramp and calculate INL, DNL
R2R DAC: measure sine, do FFT and calculate SNR for 2 frequencies

ADC characterization

Use 12-bit PMOD DAC for signal generation.

Arduino ADC: measure ramp and calculate INL, DNL with histogram test
Arduino ADC: measure sine, do FFT and calculate SNR for 2 frequencies

Change on resistor of the R2R DAC.
Measure INL, DNL and FFT
Implement software error correction in a lookup table
Measure INL, DNL and FFT improvement

Document your results in a final report.
Deadline for the report is:

Optimization of Arduino DAC & ADC Resolution

Since Arduino DAC and ADCs are set to 10 bits by default, but their resolution can be increased by accessing them via IDE sketch. The resolution of Arduino DAC is increased from 10bits to 12 bits by using the code;
analogWriteResolution(bits);
This sketch line is written before the [analogWrite(DAC, sine12);], here sine 12 given as input to let the DAC generate signal that can be tested by 12-bit ADC and then compare with the external 12-bit Pmod DAC. Below is the modified Arduino sketch for optimization of the Arduino DAC.


<!-- Arduino IDE DAC optimization Sketch -->

analogWriteResolution(12);     // Arduino DAC Resolution Change     
     analogWrite(DAC, sine12); //  //Writing Analogue to arduino DAC//

Similarly, the resolution of the ADC is increased from 10 bits to 12 and 16 bits. The results of 12-bit optimized combination are realistic and included in the report. However, it was observed that Arduino MKR WIFI 1010 has maximum accessible resolution of 12 bits, although 65,536 steps (quantization) were achieved but arduino was padding the extra bits with zeros. The following addition was made in the sketch before the serial print argument to increase the ADCs resolution.


<!-- Arduino IDE ADC optimization Sketch -->

analogReadResolution(bits);     // Arduino ADC Resolution Change

Optimization of Arduino DAC & ADC Speed

DMA allows the faster transfer from data to and from the ADC, DAC to memory. This can speed up waveform generation.

A DAC DMA Exaple was found here.
Sketch ZeroDMA_DAC.ino can be downloaded.
Setting the variable period to 199 gives a sine signal with 32 samples at a sample rate of 240 kHz.

The library Adafruit ZeroDMA gives an example sketch ZeroDMA.ino for reading 256 ADC samples at high speed (2 MHz).

Unfortunately it is difficult to merge the libraries. Change the DAC sampling to ZeroDMA library was not successful.
A general description of SAM DMA can be found here .

IRQ with ADC A4 and DAC A0

The sketch Timer_IRQ.ino realizes a 15.9 kHz sample rate with an ADC input range of 1..1.65V and DAC range from 0..3.3V.
256 8-bit values are calculated for sine lookup.

ToDo

Increase DAC samples to 256, 4096 or more
Increase ADC samples to 4096 or more
Make a fast synchronous DMA for IOs for R2R DAC
Elimante ZeroDMA library for ADC DMA sampling and merge sampling and generation
Making a nice signal generator and oscilloscope interface
Can more than one ADC input be sampled using DMA?
Adapting other boards using DMA?
Use interrupt ISR for ADC reading and DAC writing

YetAnother USB Oscilloscope

Arduino getting stuck and USB device problems

The Arduino can get stuck with infinite loops and IRQ disabled.
Pressing "RST" button twice changes COM address of the Arduino. Then downloading the Sketch 'Basic' 'Minimum' makes the Arduino again operational at the previous COM port.

Board not listed in COM Ports

Disconnect breadboard from Arduino and look if the board is recognized. A short on the breadboard can disable COM port recognition.
Inspect power connections.

Timeline of Realization

Installing IDE and Blink LED program (1 h)

Start: 10.09.2020 9:36
Pictures, Goals (2): 9:57 - 10:07
Arduino IDE 1.18.13 install: 10:09 - 10:16
Arduino IDE configure, connect: 10:17 - 10:32
First program blink LED: 10:40

Anaolg output DAC, PWM, Digital and 4 ADC input (3 h)

Analog Read
Analog Write
8 bit sine lookup table
PWM write
Digital pin write

Extension (3 h)

PMODs Doku Start Program(14:07-14:16)
Implement jitter with interpolating external DAC and changing OSC channel sequence
Implement ADC, DAC and try out 1h
Implement ramp and document 1h

Third Arduino sketch (3 h)
Resolution and DMA Investigation (6 h)

DAC, ADC Characterization with Arduino WIFI MKR 1010

Video Lecture: Laboratory

Goals:

+ Overview: Step by step

- Overview: Step by step

+ 1. Setting up Environment

- 1. Setting up Environment

Download and Installation - Arduino IDE for Home

L:\apps\Arduino click on Arduino

C++ Source code LED blink

+ 2. Sine and Analog inputs to serial port

- 2. Sine and Analog inputs to serial port