Hey everybody,
Please see my video below for a full explanation and any advice offered would be great!
Here is the code I am using:
/* code for max 7219 from maxim,
reduced and optimised for using more then one 7219 in a row,
______________________________________
General notes:
-if you are only using one max7219, then use the function maxSingle to control
the little guy ---maxSingle(register (1-8), collum (0-255))
-if you are using more then one max7219, and they all should work the same,
then use the function maxAll ---maxAll(register (1-8), collum (0-255))
-if you are using more than one max7219 and just want to change something
at one little guy, then use the function maxOne
---maxOne(Max you wane controll (1== the first one), register (1-8),
collum (0-255))
/* During initiation, be sure to send every part to every max7219 and then
upload it.
For example, if you have five max7219's, you have to send the scanLimit 5 times
before you load it-- other wise not every max7219 will get the data. the
function maxInUse keeps track of this, just tell it how many max7219 you are
using.
*/
#include <Wire.h>
int dataIn = 2; // "DIN" on module
int load = 3; // "CS" on module
int clock = 4; // ""CLK" on module
const int ledPin = 13; // the number of the LED pin
int maxInUse = 1; //change this variable to set how many MAX7219's you'll use
int ledState = LOW; // ledState used to set the LED
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,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,HIGH);
}
void maxOne(byte maxNr, byte reg, byte col) {
//maxOne is for adressing different MAX7219's,
//while 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,HIGH);
}
void putCol( byte colno, byte coldat) {
// Interprets colno as (zero ref) index in combined array
byte t;
t = colno >> 3;
byte u;
u = colno & 0x07;
maxOne(t+1, u+1, coldat);
}
void dispon () {
maxAll(max7219_reg_shutdown, 0x01); // Display on
}
void dispoff () {
maxAll(max7219_reg_shutdown, 0x00); // Display off
}
byte irow = 0; // Row index
byte icol = 0; // Column index
byte pattern; // bit mask
byte lcol; // left border
byte rcol; // right border
byte trow; // top row marker
byte brow; // bottom row marker
int s_vert; // Vertical switch
int s_horz; // Horizontal switch
// the follow variable is a long because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
long interval = 40; // interval at which to blink (milliseconds)
long previousMillis = 0; // will store last time LED was updated
int scantype = 0; // switch mode
void worker () {
if (pattern == 0) pattern = trow; // pattern must be set
if (s_vert != 0) {
if (s_vert == -1) { // moving upward
pattern = pattern >> 1;
if (pattern == trow) { // hit the top
s_vert = 0; s_horz = 1;
}
} else {
pattern = pattern << 1; // moving downward
if (pattern == brow) { // hit the bottom
s_vert = 0; s_horz = -1;
}
}
putCol(icol,pattern); // Show the column.
return;
}
if (s_horz != 0) {
putCol(icol,0); // blank previous column.
if (s_horz == -1) { // moving left
icol--;
if (icol == lcol) { // hit the side
s_horz = 0; s_vert = -1;
}
} else {
icol++; // moving right
if (icol == rcol) { // hit the side
s_horz = 0; s_vert = 1;
}
}
putCol(icol,pattern); // Show the column.
}
}
void setup () {
pinMode(dataIn, OUTPUT);
pinMode(clock, OUTPUT);
pinMode(load, OUTPUT);
pinMode(ledPin, OUTPUT);
//Serial begin(9600);
digitalWrite(13, HIGH);
//initiation of the max 7219
maxAll(max7219_reg_displayTest, 0x00); // no display test
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
for (e=1; e<=8; e++) { // empty registers, turn all LEDs off
maxAll(e,0);
}
maxAll(max7219_reg_intensity, 0x08 & 0x0f); // the first 0x0f is the value you can set
// range: 0x00 to 0x0f
pattern = 0;
scantype = 0;
s_vert = 0;
s_horz = 1;
lcol = 1; // left border
rcol = 6; // right border
trow = 0x02; // top row marker
brow = 0x40; // bottom row marker
}
void loop () {
//if you use just one MAX7219 it should look like this
/*
maxSingle(1,1); // + - - - - - - -
maxSingle(2,2); // - + - - - - - -
maxSingle(3,4); // - - + - - - - -
maxSingle(4,8); // - - - + - - - -
maxSingle(5,16); // - - - - + - - -
maxSingle(6,32); // - - - - - + - -
maxSingle(7,64); // - - - - - - + -
maxSingle(8,128); // - - - - - - - +
*/
unsigned long currentMillis = millis();
if(currentMillis - previousMillis > interval) {
// save the last time you blinked the LED
previousMillis = currentMillis;
// if the LED is off turn it on and vice-versa:
if (ledState == LOW) {
ledState = HIGH;
// Alternate 1
}
else {
ledState = LOW;
// Alternate 2
// set the LED with the ledState of the variable:
// Timed process:
worker();
}
digitalWrite(ledPin, ledState);
}
}
