MAX7219.c

/*
 * MAX7219_test.c
 *
 * Created: 23.08.2020 17:05:20
 * Author : 123
 */
#define F_CPU 16000000UL

#include <avr/io.h>
#include <util/delay.h>

#define DIN PB2
#define LOAD_CS PB1
#define CLK PB0

#define DIN_DDR DDRB
#define LOAD_CS_DDR DDRB
#define CLK_DDR DDRB

#define DIN_PORT PORTB
#define LOAD_CS_PORT PORTB
#define CLK_PORT PORTB

void SW_SPI_Init(void) {
    DIN_DDR |= (1 << DIN);
    LOAD_CS_DDR |= (1 << LOAD_CS);
    CLK_DDR |= (1 << CLK);
}

void SW_SPI_Send(unsigned char data, char lsbFirst) {
    unsigned char i = 0;
    unsigned char val = 0;
    for (i = 0; i < 8; i++) {
        if (lsbFirst) {
            val = !!(data & (1 << i));
        } else {
            val = !!(data & (1 << (7 - i)));
        }
        if (val) DIN_PORT |= (1 << DIN);
        if (!val) DIN_PORT &= ~(1 << DIN);

        CLK_PORT |= (1 << CLK);
        CLK_PORT &= ~(1 << CLK);

    }
}

void MAX7219_Send(unsigned char reg, unsigned char data) {
    LOAD_CS_PORT &= ~(1 << LOAD_CS);
    SW_SPI_Send(reg, 0);
    SW_SPI_Send(data, 0);
    LOAD_CS_PORT |= (1 << LOAD_CS);
}

void MAX7219_Clear() {
    //char i = 4;
    //do {
        MAX7219_Send(0x01, 0x0f);
        MAX7219_Send(0x02, 0x0f);
        MAX7219_Send(0x03, 0x0f);
        MAX7219_Send(0x04, 0x0f);
    //} while (-i);
}

int main(void) {

    SW_SPI_Init();

    MAX7219_Send(0x09, 0x00);
    MAX7219_Send(0x0B, 3);
    MAX7219_Send(0x0A, 0x02);
    MAX7219_Send(0x0C, 1);
    MAX7219_Clear();

    unsigned char data[14] = {
        0b00110000, // i
        0b00111101, // d,
        0b00110000, // i
        0b00000000, // \s
        0b00010101, // n,
        0b01110111, // A,
        0x00,
        0b00110111, // H,
        0b00111011, // Y
        0b00110000, // i,
        0x00,
        0x00,
        0x00,
        0x00

    };
    unsigned char display_common[4];
    unsigned char i, shift = 0;


    while (1) {
        MAX7219_Clear();

        if ((shift++) > 10) shift -= 11;
        for (i = 0; i < 4; i++) {
            display_common[i] = data[ (i-1) + shift ];
        }

        MAX7219_Send(0x01, display_common[0]);
        MAX7219_Send(0x02, display_common[1]);
        MAX7219_Send(0x03, display_common[2]);
        MAX7219_Send(0x04, display_common[3]);

        _delay_ms(500);

    }
}