Max7219 + Tutorials ... still doesn't work

I tested this tut during 3 h.
http://www.arduino.cc/playground/Main/MAX72XXHardware

I used this code:
http://www.arduino.cc/playground/LEDMatrix/Max7219

of course I modified this code with:

  • the right number of max7219,
  • the right Dout pins of my Wiring board.

it should work, it doesn’t…! :’(

any experiencies ? ideas ?

my code:
I put the Serial stuff at the end in order to watch the loop running.

int dataIn = 5;
int load = 6;
int clock = 7;

int maxInUse = 1; //change this variable to set how many MAX7219’s you’ll use

int e = 0; // just a varialble

// define max7219 registers
byte max7219_reg_noop = 0x00;
byte max7219_reg_digit0 = 0x01;
byte max7219_reg_digit1 = 0x02;
byte max7219_reg_digit2 = 0x03;
byte max7219_reg_digit3 = 0x04;
byte max7219_reg_digit4 = 0x05;
byte max7219_reg_digit5 = 0x06;
byte max7219_reg_digit6 = 0x07;
byte max7219_reg_digit7 = 0x08;
byte max7219_reg_decodeMode = 0x09;
byte max7219_reg_intensity = 0x0a;
byte max7219_reg_scanLimit = 0x0b;
byte max7219_reg_shutdown = 0x0c;
byte max7219_reg_displayTest = 0x0f;

void putByte(byte data) {
byte i = 8;
byte mask;
while(i > 0) {
mask = 0x01 << (i - 1); // get bitmask
digitalWrite( clock, LOW); // tick
if (data & mask){ // choose bit
digitalWrite(dataIn, HIGH);// send 1
}else{
digitalWrite(dataIn, LOW); // send 0
}
digitalWrite(clock, HIGH); // tock
–i; // move to lesser bit
}
}

void maxSingle( byte reg, byte col) {
//maxSingle is the “easy” function to use for a //single max7219

digitalWrite(load, LOW); // begin
putByte(reg); // specify register
putByte(col);//((data & 0x01) * 256) + data >> 1); // put data
digitalWrite(load, LOW); // and load da shit
digitalWrite(load,HIGH);
}

void maxAll (byte reg, byte col) { // initialize all MAX7219’s in the system
int c = 0;
digitalWrite(load, LOW); // begin
for ( c =1; c<= maxInUse; c++) {
putByte(reg); // specify register
putByte(col);//((data & 0x01) * 256) + data >> 1); // put data
}
digitalWrite(load, LOW);
digitalWrite(load,HIGH);
}

void maxOne(byte maxNr, byte reg, byte col) {
//maxOne is for adressing different MAX7219’s,
//whilele having a couple of them cascaded

int c = 0;
digitalWrite(load, LOW); // begin

for ( c = maxInUse; c > maxNr; c–) {
putByte(0); // means no operation
putByte(0); // means no operation
}

putByte(reg); // specify register
putByte(col);//((data & 0x01) * 256) + data >> 1); // put data

for ( c =maxNr-1; c >= 1; c–) {
putByte(0); // means no operation
putByte(0); // means no operation
}

digitalWrite(load, LOW); // and load da shit
digitalWrite(load,HIGH);
}

void setup () {

pinMode(dataIn, OUTPUT);
pinMode(clock, OUTPUT);
pinMode(load, OUTPUT);

//initiation of the max 7219
maxAll(max7219_reg_scanLimit, 0x07);
maxAll(max7219_reg_decodeMode, 0x00); // using an led matrix (not digits)
maxAll(max7219_reg_shutdown, 0x01); // not in shutdown mode
maxAll(max7219_reg_displayTest, 0x00); // no display test
for (e=1; e<=8; e++) { // empty registers, turn all LEDs off
maxAll(e,0);
}
maxAll(max7219_reg_intensity, 0x0f & 0x0f); // the first 0x0f is the value you can set
// range: 0x00 to 0x0f
}

void loop () {
Serial.begin(9600);
Serial.println(“okk”);

maxSingle(1,4);
maxSingle(2,2);
delay(2000);
maxSingle(1,0);
maxSingle(2,0);
}

initializing the serial port should probably be under setup() instead of in the loop()

I'm having trouble with the max7219 myself but I'm thinking its because I'm missing something in the circuit. I've just got wires going directly from the arudino board to the data in, clock and load pins

indeed, initialize Serial port for every loop isn't efficient and optimized ;D

but, it isn't the problem. as you wrote, I may miss something in the wires... grrrr :(

Put a 10k pull-down resistor on each of the 3 inputs, i.e. between ground and each of DataIN, CS and CLK.

This can help prevent it going into test mode while the arduino is booting up.

nice tip.. I'll test that in few minutes!