Monday, June 17, 2013

Six channel 3 Million samples per second Arduino powered logic analyzer

I DID IT!  I not only got the six channel logic analyzer to work, but I have also succeeded in breaking the 2 million samples per second limit.
Here is the video of it working on YouTube: YouTube Video
Here is a close up of the screen showing the outputs of a 74LS390, with a 10 MC clock input.  The top trace is 100 KC and the bottom one is 1 MC.
How did I do it?  The sample rate is much faster, if you code it like this:


It takes a while to type in the code, but using a "loop" slows the sampling time down by more than 50%!

Blogger keeps trashing my code buy hopefully here it is;
128 by 64 LCD Logic Analyzer 6 channel and 3Mb/s
By Bob Davis
Uses Universal 8bit Graphics Library,
  Copyright (c) 2012,   All rights reserved.

#include "U8glib.h"

// 8Bit Com: D0..D7: 8,9,10,11,4,5,6,7 en=18, di=17,rw=16
//U8GLIB_ST7920_128X64_4X u8g(8, 9, 10, 11, 4, 5, 6, 7, 18, 17, 16); 
//  **** NOTE **** I Moved the three control pins !!!
U8GLIB_ST7920_128X64_4X u8g(8, 9, 10, 11, 4, 5, 6, 7, 1, 2, 3); 

int Sample[128];
int Input=0;
int OldInput=0;
int xpos=0;
void u8g_prepare(void) {
void DrawMarkers(void) {
  u8g.drawFrame (0,0,128,64);
  u8g.drawPixel (20,1);
  u8g.drawPixel (40,1);
  u8g.drawPixel (60,1);
  u8g.drawPixel (80,1);
  u8g.drawPixel (100,1);
  u8g.drawPixel (20,62);
  u8g.drawPixel (40,62);
  u8g.drawPixel (60,62);
  u8g.drawPixel (80,62);
  u8g.drawPixel (100,62);

void draw(void) {
// wait for a trigger of a positive going input
  while (Input != 1){
// collect the analog data into an array
// No loop is about 50% faster!
    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;
// display the collected analog data from array
  for(int xpos=0; xpos<128; xpos++) {
    u8g.drawLine (xpos, ((Sample[xpos]&B00000001)*4)+4, xpos, ((Sample[xpos+1]&B00000001)*4)+4);
    u8g.drawLine (xpos, ((Sample[xpos]&B00000010)*2)+14, xpos, ((Sample[xpos+1]&B00000010)*2)+14);
    u8g.drawLine (xpos, ((Sample[xpos]&B00000100)*1)+24, xpos, ((Sample[xpos+1]&B00000100)*1)+24);
    u8g.drawLine (xpos, ((Sample[xpos]&B00001000)/2)+34, xpos, ((Sample[xpos+1]&B00001000)/2)+34);
    u8g.drawLine (xpos, ((Sample[xpos]&B00010000)/4)+44, xpos, ((Sample[xpos+1]&B00010000)/4)+44);
    u8g.drawLine (xpos, ((Sample[xpos]&B00100000)/8)+54, xpos, ((Sample[xpos+1]&B00100000)/8)+54);

void setup(void) {
  pinMode(A0, INPUT);
  pinMode(A1, INPUT);
  pinMode(A2, INPUT);
  pinMode(A3, INPUT);
  pinMode(A4, INPUT);
  pinMode(A5, INPUT);

  // assign default color value
  if ( u8g.getMode() == U8G_MODE_R3G3B2 ) 
    u8g.setColorIndex(255);     // RGB=white
  else if ( u8g.getMode() == U8G_MODE_GRAY2BIT )
    u8g.setColorIndex(3);       // max intensity
  else if ( u8g.getMode() == U8G_MODE_BW )
    u8g.setColorIndex(1);       // pixel on, black

void loop(void) {
// picture loop  
//  u8g.firstPage();  
  do { draw(); }  
  while( u8g.nextPage() );
  // rebuild the picture after some delay


Joldosh said...

Nice project! Which LCD are you using?

Bajdi Electronics said...

That's pretty amazing, are you willing to share the code?

Bajdi Electronics said...

That's pretty amazing, are you willing to share the code?

Bajdi Electronics said...

That's pretty amazing, are you willing to share the code?

Goebish said...

Nice !
Any chance you publish the complete source code ?

Bob Davis said...

I will try to add the code, but it is very loooong.

Goebish said...

Thank you very much !

Thargis said...

What display model was applied?

Thargis said...

What display model was applied?

Hemal said...

Great work!
Can you please post the code on github or goolge code, this will be helpful
Thank you.

Irregular Shed said...

Very nice work! I remember from my Z80 coding days that loops could slow things down a lot (I was telling a far-too-young colleague yesterday about having to use stack manipulation to copy data around at the highest speed possible before he was born...)

Bob Davis said...

the LCD was a QC12864 purchased on eBay.

Alex Walker said...

Hey. This is very amazing and nice code. And also it is very attractive project. Would you like to share this code?

visit my site Gmail Tech Support

Thanks & Regards

Alfanso Thomas

Dano said...

Cool, I like it!

You might try replacing this:
while (Input != 1){ Input=digitalRead(A0);}

with this:
while(!(PINC & 0x01));

It will probably help your trigger flitter, as it is much quicker.

Andrew Gillham said...

Very cool Bob, nice work.

I added some faster sample rates for my Arduino based logic analyzer based on your tests. I found that 2MHz & 4MHz sample rates worked well. The "flat out" rate the ATmega328 @ 16MHz can do is 5.333MHz but the timing calculations didn't work out that well with the SUMP client at that rate.

I used a simple shell script like this to spit out the code:

while [ $A -lt 7168 ]
echo logicdata[$A] = CHANPIN\;
A=`expr $A + 1`

My logic analyzer has a thread on the Arduino forums also: