1.3K
This is a picture of the 8 x 8 LED matrix display I used which I connected to my ATmega16
Here are the connections
CS -> PORTD 2
DIN -> PORTD 1
CLK -> PORTD 0
Schematic
Code
[codesyntax lang=”c”]
#define CS_Pin PORTD.F2 #define DIN_Pin PORTD.F1 #define CLK_Pin PORTD.F0 unsigned const short Alphabet[156]={ 0x7f, 0x88, 0x88, 0x88, 0x88, 0x7f, // A 0x6e, 0x91, 0x91, 0x91, 0x91, 0xff, // B 0x42, 0x81, 0x81, 0x81, 0x81, 0x7E, // C 0x7e, 0x81, 0x81, 0x81, 0x81, 0xff, // D 0x91, 0x91, 0x91, 0x91, 0xff, 0x81, // E 0x80, 0x90, 0x90, 0x91, 0xff, 0x81, // F 0x4e, 0x89, 0x89, 0x81, 0x81, 0x7e, // G 0xff, 0x10, 0x10, 0x10, 0x10, 0xff, // H 0x00, 0x81, 0xff, 0xff, 0x81, 0x00, // I 0x00, 0x80, 0xfe, 0x81, 0x01, 0x06, // J 0x81, 0xc3, 0x24, 0x99, 0xff, 0x81, // K 0x03, 0x01, 0x01, 0x81, 0xff, 0x81, // L 0xff, 0x60, 0x18, 0x18, 0x60, 0xff, // M 0xff, 0x06, 0x08, 0x10, 0x60, 0xff, // N 0x7e, 0x81, 0x81, 0x81, 0x81, 0x7e, // O 0x70, 0x88, 0x88, 0x89, 0xff, 0x81, // P 0x7e, 0x87, 0x89, 0x85, 0x81, 0x7e, // Q 0x61, 0x93, 0x94, 0x98, 0x98, 0xff, // R 0x4e, 0x91, 0x91, 0x91, 0x91, 0x62, // S 0xc0, 0x81, 0xff, 0xff, 0x81, 0xc0, // T 0xfe, 0x01, 0x01, 0x01, 0x01, 0xfe, // U 0xfc, 0x02, 0x01, 0x01, 0x02, 0xfc, // V 0xff, 0x02, 0x04, 0x04, 0x02, 0xff, // W 0xc3, 0x24, 0x18, 0x18, 0x24, 0xc3, // X 0xc0, 0x20, 0x1f, 0x1f, 0x20, 0xc0, // Y 0xc3, 0xa1, 0x91, 0x89, 0x85, 0xc3, // Z }; void SPI_Write_Byte(unsigned short num) { unsigned short t, Mask, Flag; CLK_Pin = 0; Mask = 128; for (t=0; t<8; t++) { Flag = num & Mask; if(Flag == 0) { DIN_Pin = 0; } else { DIN_Pin = 1; } CLK_Pin = 1; CLK_Pin = 0; Mask = Mask >> 1; } } void MAX7219_INIT() { // Set BCD decode mode CS_Pin = 0; // CS pin is pulled LOW SPI_Write_Byte(0x09); // Select Decode Mode register SPI_Write_Byte(0x00); // Select BCD mode for digits DIG0-DIG7 CS_Pin = 1; // CS pin is pulled HIGH // Set display brighness CS_Pin = 0; // CS pin is pulled LOW SPI_Write_Byte(0x0A); // Select Intensity register SPI_Write_Byte(0x05); // Set brightness CS_Pin = 1; // CS pin is pulled HIGH // Set display refresh CS_Pin = 0; // CS pin is pulled LOW SPI_Write_Byte(0x0B); // Select Scan-Limit register SPI_Write_Byte(0x07); // Select digits DIG0-DIG3 CS_Pin = 1; // CS pin is pulled HIGH // Turn on the display CS_Pin = 0; // CS pin is pulled LOW SPI_Write_Byte(0x0C); SPI_Write_Byte(0x01); CS_Pin = 1; // CS pin is pulled HIGH // Disable Display-Test CS_Pin = 0; // CS pin is pulled LOW SPI_Write_Byte(0x0F); // Select Display-Test register SPI_Write_Byte(0x00); // Disable Display-Test CS_Pin = 1; // CS pin is pulled HIGH } void Write_Byte(unsigned short myColumn, unsigned short myValue) { CS_Pin = 0; // select max7219. SPI_Write_Byte(myColumn); // send myColumn value to max7219 (digit place). SPI_Write_Byte(myValue); // send myValue value to max7219 (digit place). CS_Pin = 1; // deselect max7219. } // This is clear matrix function. void Clear_Matrix(void) { unsigned short x; for(x=1;x<9;x++) { Write_Byte(x,0x00); } } void Write_Char(char myChar) { unsigned short Column, Start_Byte; // Clear the display first. Clear_Matrix(); // The next line defines our byte, from which to start the array. Start_Byte = (myChar - 65) * 6; // 65 represents the letter "A" in ASCII code. // We are using only columns from 2 through 7 for displaying the character. for(Column=2;Column<8;Column++) { Write_Byte(Column, Alphabet[Start_Byte++]); } } void main() { unsigned int x; DDRD=0xFF; MAX7219_INIT(); // initialize max7219 do{ for(x=65;x<=90;x++) // Increment with 1, from 65 until 90. { Write_Char(x); Delay_ms(1000); // This is our delay, between two consecutive character. } }while(1); }
[/codesyntax]
Links
MAX7219 Dot Matrix Module Display DIY kit
MAX7219 Dot matrix module display module