3 Digit Led

Ok, let’s try this again… I was going to have my other topic unlocked but i didn’t want to get confused nor did i want anyone else to be as well.

i just received a pair of COMMON CATHODE 3 Digit Led’s… I have tested them both and unfortunately one is defective and i’m waiting for the replacement.

Here is the pin layout - the X’s are the COMMON CATHODES:
X A F X X B

E D DP C G

They are connected to their corresponding segments on a MAX7219, the only one that is NOT connected is the DP simply because i have no use for it at all.

Here is the code i have that was given to me in the other topic, unfortunately it does NOT work, all it displays is 888

#include <SPI.h>

// set up names for the 14 MAX7219 registers:
const byte MAX7219_REG_NOOP        = 0x00;
// codes 1 to 8 are digit positions 1 to 8, see below
const byte MAX7219_REG_DECODEMODE  = 0x09;
const byte MAX7219_REG_INTENSITY   = 0x0A;
const byte MAX7219_REG_SCANLIMIT   = 0x0B;
const byte MAX7219_REG_SHUTDOWN    = 0x0C;
// registers 0x0D and 0x0E are not used
const byte MAX7219_REG_DISPLAYTEST = 0x0F;
// you have 3 digits, so
const byte MAX7219_DIG0        = 0x01;
const byte MAX7219_DIG1        = 0x02;
const byte MAX7219_DIG2        = 0x03;

// 0x00,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F are same as 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15

// and 3 variables to hold data - you will change these later to have different things displayed
byte digit0 = 3;
byte digit1 = 6;
byte digit2 = 9;

byte latchPin = 10; // or whatever pin you used
// 13 SCK will connect to MAX7219 clock
// 11 MOSI will connect to MAX7219 serial data in

// now put some data in the MAX7219 registers, and setup the latchPin - backing off from the function calls

void setup () 
  {
Serial.begin(9600); // setup serial communications for debugging
pinMode (latchPin, OUTPUT);
digitalWrite (latchPin, HIGH);

// turn on SPI library - sets  up the internal hardware for SCK, MISO, MOSI
SPI.begin (); // transfers to the MAX7219 will use default speed of 4 MHz

// now setup the 5 registers that control things
digitalWrite (latchPin, LOW);
SPI.transfer (MAX7219_REG_SCANLIMIT);      // send address
SPI.transfer (2); // send data to show 3 digits
digitalWrite (latchPin,  HIGH); // data latched on this signal going Low to High

//continue for the other registers
digitalWrite (latchPin, LOW);
SPI.transfer (MAX7219_REG_DECODEMODE);      // send address
SPI.transfer (0xFF); // use internal mapping to create the digits
digitalWrite (latchPin,  HIGH); // data latched on this signal going Low to High

//continue for the other registers
digitalWrite (latchPin, LOW);
SPI.transfer (MAX7219_REG_DISPLAYTEST);      // send address
SPI.transfer (0); // no display test (display test on turns on all segments)
digitalWrite (latchPin,  HIGH); // data latched on this signal going Low to High

//continue for the other registers
digitalWrite (latchPin, LOW);
SPI.transfer (MAX7219_REG_INTENSITY);      // send address
SPI.transfer (7); // mid level intensity, 0 to 15
digitalWrite (latchPin,  HIGH); // data latched on this signal going Low to High

//continue for the other registers
digitalWrite (latchPin, LOW);
SPI.transfer (MAX7219_REG_SHUTDOWN);      // send address
SPI.transfer (1); // 1 = not shutdown mode
digitalWrite (latchPin,  HIGH); // data latched on this signal going Low to High

// MAX7219 control registers all set, send some data!
Serial.println ("MAX7219 Setup done");

//continue for the data registers
digitalWrite (latchPin, LOW);
SPI.transfer (MAX7219_DIG0);      // send address
SPI.transfer (digit0); // data
digitalWrite (latchPin,  HIGH); // data latched on this signal going Low to High

//continue for the data registers
digitalWrite (latchPin, LOW);
SPI.transfer (MAX7219_DIG1);      // send address
SPI.transfer (digit1); // 1 = not shutdown mode
digitalWrite (latchPin,  HIGH); // data latched on this signal going Low to High

//continue for the other registers
digitalWrite (latchPin, LOW);
SPI.transfer (MAX7219_DIG2);      // send address
SPI.transfer (digit2); // 1 = not shutdown mode
digitalWrite (latchPin,  HIGH); // data latched on this signal going Low to High

Serial.println ("End of Setup");
}   // end of setup
void loop(){
}

What i want to accomplish is: to control a 10x10 LED MATRIX
These buttons control the 3 Digit Led, but each button will have 2 jobs…
Button 1: A/1
Button 2: B/2
Button 3: C/3
Button 4: D/4
Button 5: E/5
Button 6: F/6
Button 7: G/7
Button 8: H/8
Button 9: I/9
Button 10: J/10

So, if i wanted to display “e08” i would press button 5 and then button 8. Also i assume i would have to multiplex the buttons somehow with another chip?

We’ll get to the following soon:
Button 11: Clear
Button 12: Enter
Button 13: Fleet

You have MAX7219 pin connected to +5 with a 25K-30K resistor?
You have 10uF and 0.1u cap from pin 19 to Gnd?

i don't have a cap connected yet... but i can

too big to post

No caps, but 2 resistors?

was from the last topic.. so i just left them there.. so do i take out the resistor from 19 and put a cap there instead?

Sounds like your’re close.
You should learn a schematic capture tool. Very useful.

Another view of the same thing:

yes, that's how i have it.. and now nothing lights up

Hi, your picture shows two orange wires going up to the negative power bus, but no connection to the other neg power bus that is connected to the arduino gnd.
I think it is pins 3 and 9, they will not be at gnd.
You have to connect externally the two neg busses that run the length of the protoboard as well as the two positive busses.
They are not connected under the board.
Do you have a DMM to help you check your circuit?
Tom...... :slight_smile:

and i do not have a DMM

HI, fine on the earth busses, is the project upside down or is the display in upside down?

Tom... :slight_smile:

and i do not have a DMM

Then, you should put the Arduino (or this project) away until you get one.

TomGeorge:
is the project upside down or is the display in upside down?

Tom... :slight_smile:

nope..

i gave you everything i have, how it's wired and all... i don't need a meter to tell me anything... it's all wired up right...

I don't have access to image hosts on this computer. Any way you can resize as necessary and upload the image directly to the forum? Guaranteed to get more views that way. (Well, at least one more.)