Thursday, June 27, 2013

Arduino powered 5 Million samples per second oscope with CA3306

This Arduino powered 5 Million samples per second oscilloscope uses an external CA3306 analog to digital converter.  the Ca3306 produces less glitches than the AD775 did.  Here is the video on YouTube.   I fixed the memory issue and even sped it up some more by changing the array from 320 integers to 240 bytes.  Integers are 16 bits long and bytes are 8 bits long, so it is much faster and uses less memory. 

I also added a trigger and speed selection switch on D12 and D13 to ground.  The speed selection has 10 modes.  They range from no loop, to a loop with no delay, to eight available delay settings.

Here is a picture of the screen of the oscilloscope running in its fastest mode.

Here is a picture of the CA3306 wiring, it is much easier than the other Analog to digital converter was.

Here is the CA3306 schematic diagram;
Here is a oscilloscope like input section schematic.  I used two 9 volt batteries to test it out.  It give the ability to handle inputs of up to 50 volts and also allows gain selection. It is a much simpler design than the input section that was in my book "Digital and Computer projects".

Here is the code.  It uses two push buttons, one on D12 and one on D13 to select the sample rate and the trigger level.  To be honest the trigger does not work very well yet.
// Three color 5msps ext AtoD Scope
// By Bob Davis
// UTFT_(C)2012 Henning Karlsen
// web:
// Switches on D12 & D13 determine sweep speed and trigger level

// Declare which fonts we will be using
extern uint8_t SmallFont[];
extern uint8_t BigFont[];
extern uint8_t SevenSegNumFont[];

// Note that the control pins are now assigned to 8-11
UTFT myGLCD(ILI9325C,8,9,10,11);  
int Input=0;
byte Sample[320];
byte OldSample[320];
int StartSample=0;
int EndSample=0;
int MaxSample=0;
int MinSample=0;
int mode=0;
int dTime=1;
int Trigger=10;
int SampleSize=0;
int SampleTime=0;

void DrawMarkers(){
  myGLCD.setColor(0, 220, 0);
  myGLCD.drawLine(0, 0, 0, 240);
  myGLCD.drawLine(60, 0, 60, 240);
  myGLCD.drawLine(120, 0, 120, 240);
  myGLCD.drawLine(180, 0, 180, 240);
  myGLCD.drawLine(239, 0, 239, 240);
  myGLCD.drawLine(319, 0, 319, 240);
  myGLCD.drawLine(0, 0, 319, 0);
  myGLCD.drawLine(0, 60, 319, 60);
  myGLCD.drawLine(0, 120, 319, 120);
  myGLCD.drawLine(0, 180, 319, 180);
  myGLCD.drawLine(0, 239, 319, 239);

void setup() {
  pinMode(12, INPUT);
  digitalWrite(12, HIGH);
  pinMode(13, INPUT);
  digitalWrite(13, HIGH);
  pinMode(14, INPUT);
  pinMode(15, INPUT);
  pinMode(16, INPUT);
  pinMode(17, INPUT);
  pinMode(18, INPUT);
  pinMode(19, INPUT);

void loop() {
// Set the background color(Red, Green, Blue) 
  myGLCD.setBackColor(0, 0, 0);
  char buf[12]; 
  while(1) {
    if (digitalRead(13) == 0) mode++;
    if (mode > 10) mode=0;
// Select delay times for scan modes
    if (mode == 0) dTime=0;
    if (mode == 1) dTime=0;
    if (mode == 2) dTime=1;
    if (mode == 3) dTime=2;
    if (mode == 4) dTime=5;
    if (mode == 5) dTime=10;
    if (mode == 6) dTime=20;
    if (mode == 7) dTime=50;
    if (mode == 8) dTime=100;
    if (mode == 9) dTime=200;
    if (mode == 10) dTime=500;
// Select trigger level
    if (digitalRead(12) == 0) Trigger=Trigger+10;
    if (Trigger > 50) Trigger=0;
// Wait for input to be greater than trigger
  while (Input < Trigger){
    Input = PINC;

// Collect the analog data into an array
  if (mode == 0) {
// Read analog port as a parallel port no loop
  StartSample = micros();
    Sample[1]=PINC;     Sample[2]=PINC;    Sample[3]=PINC;    
    Sample[4]=PINC;     Sample[5]=PINC;    Sample[6]=PINC;
    Sample[7]=PINC;     Sample[8]=PINC;    Sample[9]=PINC;
    Sample[10]=PINC;    Sample[11]=PINC;    Sample[12]=PINC;
    Sample[13]=PINC;    Sample[14]=PINC;    Sample[15]=PINC;
    Sample[16]=PINC;    Sample[17]=PINC;    Sample[18]=PINC;
    Sample[19]=PINC;    Sample[20]=PINC;    Sample[21]=PINC;
    Sample[22]=PINC;    Sample[23]=PINC;    Sample[24]=PINC;
    Sample[25]=PINC;    Sample[26]=PINC;    Sample[27]=PINC;
    Sample[28]=PINC;    Sample[29]=PINC;    Sample[30]=PINC;
    Sample[31]=PINC;    Sample[32]=PINC;    Sample[33]=PINC;
    Sample[34]=PINC;    Sample[35]=PINC;    Sample[36]=PINC;
    Sample[37]=PINC;    Sample[38]=PINC;    Sample[39]=PINC;
    Sample[40]=PINC;    Sample[41]=PINC;    Sample[42]=PINC;
    Sample[43]=PINC;    Sample[44]=PINC;    Sample[45]=PINC;
    Sample[46]=PINC;    Sample[47]=PINC;    Sample[48]=PINC;
    Sample[49]=PINC;    Sample[50]=PINC;    Sample[51]=PINC;
    Sample[52]=PINC;    Sample[53]=PINC;    Sample[54]=PINC;
    Sample[55]=PINC;    Sample[56]=PINC;    Sample[57]=PINC;
    Sample[58]=PINC;    Sample[59]=PINC;    Sample[60]=PINC;
    Sample[61]=PINC;    Sample[62]=PINC;    Sample[63]=PINC;
    Sample[64]=PINC;    Sample[65]=PINC;    Sample[66]=PINC;
    Sample[67]=PINC;    Sample[68]=PINC;    Sample[69]=PINC;
    Sample[70]=PINC;    Sample[71]=PINC;    Sample[72]=PINC;
    Sample[73]=PINC;    Sample[74]=PINC;    Sample[75]=PINC;
    Sample[76]=PINC;    Sample[77]=PINC;    Sample[78]=PINC;
    Sample[79]=PINC;    Sample[80]=PINC;    Sample[81]=PINC;
    Sample[82]=PINC;    Sample[83]=PINC;    Sample[84]=PINC;
    Sample[85]=PINC;    Sample[86]=PINC;    Sample[87]=PINC;
    Sample[88]=PINC;    Sample[89]=PINC;    Sample[90]=PINC;
    Sample[91]=PINC;    Sample[92]=PINC;    Sample[93]=PINC;
    Sample[94]=PINC;    Sample[95]=PINC;    Sample[96]=PINC;
    Sample[97]=PINC;    Sample[98]=PINC;    Sample[99]=PINC;
    Sample[100]=PINC;    Sample[101]=PINC;    Sample[102]=PINC;
    Sample[103]=PINC;    Sample[104]=PINC;    Sample[105]=PINC;
    Sample[106]=PINC;    Sample[107]=PINC;    Sample[108]=PINC;
    Sample[109]=PINC;    Sample[110]=PINC;    Sample[111]=PINC;
    Sample[112]=PINC;    Sample[113]=PINC;    Sample[114]=PINC;
    Sample[115]=PINC;    Sample[116]=PINC;    Sample[117]=PINC;
    Sample[118]=PINC;    Sample[119]=PINC;    Sample[120]=PINC;
    Sample[121]=PINC;    Sample[122]=PINC;    Sample[123]=PINC;
    Sample[124]=PINC;    Sample[125]=PINC;    Sample[126]=PINC;
    Sample[127]=PINC;    Sample[128]=PINC;    Sample[129]=PINC;
    Sample[130]=PINC;    Sample[131]=PINC;    Sample[132]=PINC;
    Sample[133]=PINC;    Sample[134]=PINC;    Sample[135]=PINC;
    Sample[136]=PINC;    Sample[137]=PINC;    Sample[138]=PINC;
    Sample[139]=PINC;    Sample[140]=PINC;    Sample[141]=PINC;
    Sample[142]=PINC;    Sample[143]=PINC;    Sample[144]=PINC;
    Sample[145]=PINC;    Sample[146]=PINC;    Sample[147]=PINC;
    Sample[148]=PINC;    Sample[149]=PINC;    Sample[150]=PINC;
    Sample[151]=PINC;    Sample[152]=PINC;    Sample[153]=PINC;
    Sample[154]=PINC;    Sample[155]=PINC;    Sample[156]=PINC;
    Sample[157]=PINC;    Sample[158]=PINC;    Sample[159]=PINC;
    Sample[160]=PINC;    Sample[161]=PINC;    Sample[162]=PINC;
    Sample[163]=PINC;    Sample[164]=PINC;    Sample[165]=PINC;
    Sample[166]=PINC;    Sample[167]=PINC;    Sample[168]=PINC;
    Sample[169]=PINC;    Sample[170]=PINC;    Sample[171]=PINC;
    Sample[172]=PINC;    Sample[173]=PINC;    Sample[174]=PINC;
    Sample[175]=PINC;    Sample[176]=PINC;    Sample[177]=PINC;
    Sample[178]=PINC;    Sample[179]=PINC;    Sample[180]=PINC;
    Sample[181]=PINC;    Sample[182]=PINC;    Sample[183]=PINC;
    Sample[184]=PINC;    Sample[185]=PINC;    Sample[186]=PINC;
    Sample[187]=PINC;    Sample[188]=PINC;    Sample[189]=PINC;
    Sample[190]=PINC;    Sample[191]=PINC;    Sample[192]=PINC;
    Sample[193]=PINC;    Sample[194]=PINC;    Sample[195]=PINC;
    Sample[196]=PINC;    Sample[197]=PINC;    Sample[198]=PINC;
    Sample[199]=PINC;    Sample[200]=PINC;    Sample[201]=PINC;
    Sample[202]=PINC;    Sample[203]=PINC;    Sample[204]=PINC;
    Sample[205]=PINC;    Sample[206]=PINC;    Sample[207]=PINC;
    Sample[208]=PINC;    Sample[209]=PINC;    Sample[210]=PINC;
    Sample[211]=PINC;    Sample[212]=PINC;    Sample[213]=PINC;
    Sample[214]=PINC;    Sample[215]=PINC;    Sample[216]=PINC;
    Sample[217]=PINC;    Sample[218]=PINC;    Sample[219]=PINC;    
    Sample[220]=PINC;    Sample[221]=PINC;    Sample[222]=PINC;
    Sample[223]=PINC;    Sample[224]=PINC;    Sample[225]=PINC;
    Sample[226]=PINC;    Sample[227]=PINC;    Sample[228]=PINC;
    Sample[229]=PINC;    Sample[230]=PINC;    Sample[231]=PINC;
    Sample[232]=PINC;    Sample[233]=PINC;    Sample[234]=PINC;
    Sample[235]=PINC;    Sample[236]=PINC;    Sample[237]=PINC;
    Sample[238]=PINC;    Sample[239]=PINC;    Sample[240]=PINC;
  EndSample = micros();
  if (mode == 1) {
// Read analog port as a parallel port no delay
  StartSample = micros();
  for(int xpos=0; xpos<240; xpos++) {
  EndSample = micros();
  if (mode >= 2) {
// Read analog port as a parallel port variable delay
  StartSample = micros();
  for(int xpos=0; xpos<240; xpos++) {
  EndSample = micros();

// Display the collected analog data from array
  for(int xpos=0; xpos<239; xpos++) {
// Erase the old stuff
    myGLCD.setColor(0, 0, 0);
    myGLCD.drawLine (xpos+1, 255-OldSample[xpos+1]*4, xpos+2, 255-OldSample[xpos+2]*4);  
    if (xpos==0) myGLCD.drawLine (xpos+1, 1, xpos+1, 239);
// Draw the new data
    myGLCD.setColor(255, 255, 255);
    myGLCD.drawLine (xpos, 255-Sample[xpos]*4, xpos+1, 255-Sample[xpos+1]*4); 

//  Determine sample voltage peak to peak
  MaxSample = Sample[100];
  MinSample = Sample[100];
  for(int xpos=0; xpos<240; xpos++) {
    OldSample[xpos] = Sample[xpos];  
    if (Sample[xpos] > MaxSample) MaxSample=Sample[xpos];
    if (Sample[xpos] < MinSample) MinSample=Sample[xpos];
// display the sample time, delay time and trigger level  
  myGLCD.setColor(0, 0, 255);
  myGLCD.print("uSec.", 240, 10);
  myGLCD.print("     ", 240, 30);
  myGLCD.print(itoa(SampleTime, buf, 10), 240, 30);
  myGLCD.print("Delay", 240, 70);
  myGLCD.print("     ", 240, 90);
  myGLCD.print(itoa(dTime, buf, 10), 240, 90);
  myGLCD.print("Trig.", 240, 130);
  myGLCD.print(itoa(Trigger, buf, 10), 240, 150);
// Range of 0 to 64 * 78 = 4992 mV
  myGLCD.print("mVolt", 240, 190);
  myGLCD.print(itoa(SampleSize, buf, 10), 240, 210);


Unknown said...

This is great! I was trying to make my own DSO too, But I was trying to use an ADC from Texas Instruments. I got a question. Where are you generating the clock signal for the ADC? I was using one pin of the arduino to generate the clock signal, and it wasnt very fast. With a bare stellaris launchpad, I can get almost 1Msps, check this out,

Unknown said...

check out the pga113 as your scope frontend. It's super easy to use

Unknown said...

Great project! Before I used MCP3xxx or the ADS7818 ADCs, but with maximum speed of 2 x 250ksps. I expand this project to two channels, channel one on Arduino Pin A0...A5, channel two on D0...D5. The GLCD Display is a little bit smaller (ITDB02-2.2SP) with SPI Connection on Pin D9,D10,D11 and D13 with UTFT-Lib). For 2x200 samples it needs about 80┬Ás (2x2,5 Msps).

Unknown said...

how to give the clock from arduino?Secondly how to do the same withe arduino Mega2560?

Bob Davis said...

I have not solved the clock problem yet. Try using a 16MHz clock and then jumpering it through a small cap to the Arduino clock (pin 9 I think).

Shai said...

Great work! Is the above schematic complete? It doesn't seem to show all the parts. Am I missing something?

Bob Davis said...

The schematic does not show the analog input section or the LCD screen. They can be found in my book "Arduino Oscilloscope Projects".

Shai said...

Great book with LOTS of detail! Nice work! I'll work on putting one of these together with the TLC5510 one day.

Fenris said...

Hey Bob, maybe I'm late to the party but I was wondering a few things.

1- Why not using 2 CA3306 ADCs phased out to be able to reach 10 MSamples? (I know for a fact that Rigol is doing such a thing on their cheaper models. Even Overclocking them).

2- What about using a cortex-m0 or even m3 board? (they are really cheap nowadays, they can be integrated on the Arduino IDE). I saw those boards compared with Arduino generating graphics on a screen and... THEY ARE REALLY FAST in comparison to Arduino!

These are just a couple of ideas.
I would appreciate your opinion about them, and why yes or why not, and alternatives to it. If my ideas are not interesting enough but I can, somehow, spark new ideas ... I'll be happy with that! ^_^

Fer said...

Hi, I have built a smally oscilloscope based in your hardware desing. I am very happy.

Bob Davis said...

DIYFanatic - You can overclock the Arduino and even sync it with an ADC, but that is not something the average person can easily do. If you use an external oscillator and inject the signal to pin 9 (If I remember right) then the Arduino will run much faster.