Hi,
I tried to chain four 8x8 LED matrix with backpack I got from Sparkfun. I already configure each of them. But I don’t have a code to test.
Does anyone has simple code examples I can run test. I’d like to have effect like the message would go over from the
This is the code I use, but only works for one LED backpack, if I connect 3 more, they’d only display the same image with the first one.
// Simple program to test using the Arduino with the RGB Matrix
// & Backpack from Sparkfun. Code is a combination of Heather Dewey-Hagborg,
// Arduino Forum user: Little-Scale, and // Daniel Hirschmann. Enjoy!
//
// The Backpack requires 125Khz SPI, which is the slowest rate
// at which the Arduino’s hardware SPI bus can communicate at.
//
// We need to send SPI to the backpack in the following steps:
// 1) Activate ChipSelect;
// 2) Wait 500microseconds;
// 3) Transfer 64bytes @ 125KHz (1 byte for each RGB LED in the matrix);
// 4) De-activate ChipSelect;
// 5) Wait 500microseconds
// Repeat however often you like!
#define CHIPSELECT 10//ss
#define SPICLOCK 13//sck
#define DATAOUT 11//MOSI / DI
#define DATAIN 12//MISO / DO
int data =
{0,0,0,0,0,0,0,0,
0,0,0xE0,0xE0,0xE0,0,0,0,
0,0xE0,0,0xE0,0xE0,0,0,0,
0,0,0xE0,0xE0,0xE0,0xE0,0,0,
0,0,0xE0,0xE0,0xE0,0xE0,0,0,
0,0,0xE0,0xE0,0xE0,0xE0,0,0,
0,0,0xE0,0xE0,0xE0,0xE0,0,0,
0,0,0,0xE0,0xE0,0,0,0
};
char spi_transfer(volatile char data)
{
SPDR = data; // Start the transmission
while (!(SPSR & (1<<SPIF))) // Wait the end of the transmission
{
};
}
void setup()
{
byte clr;
pinMode(DATAOUT,OUTPUT);
pinMode(SPICLOCK,OUTPUT);
pinMode(CHIPSELECT,OUTPUT);
digitalWrite(CHIPSELECT,HIGH); //disable device
SPCR = B01010001; //SPI Registers
SPSR = SPSR & B11111110; //make sure the speed is 125KHz
/*
SPCR bits:
7: SPIEE - enables SPI interrupt when high
6: SPE - enable SPI bus when high
5: DORD - LSB first when high, MSB first when low
4: MSTR - arduino is in master mode when high, slave when low
3: CPOL - data clock idle when high if 1, idle when low if 0
2: CPHA - data on falling edge of clock when high, rising edge when low
1: SPR1 - set speed of SPI bus
0: SPR0 - set speed of SPI bus (00 is fastest @ 4MHz, 11 is slowest @ 250KHz)
*/
clr=SPSR;
clr=SPDR;
delay(10);
}
void loop()
{
delay(100);
int index = 0;
digitalWrite(CHIPSELECT,LOW); // enable the ChipSelect on the backpack
delayMicroseconds(500);
for (int i=0;i<8;i++) for (int j=0;j<8;j++)
{
spi_transfer(data[index]);
index++;
// There are only 8 colours available to the matrix with the
// backpack, so this will present 1 colour per column on the matrix
}
digitalWrite(CHIPSELECT,HIGH); // disable the ChipSelect on the backpack
delayMicroseconds(500);
}
Any suggestions is appreciated! Thanks!!
Elim