interfacing-multiple-displays-through-max7219-using-stm32

#include "main.h"
#include "max7219.h"

uint8_t disp1ay[38][8]={
{0x3C,0x42,0x42,0x42,0x42,0x42,0x42,0x3C},  //0
{0x10,0x30,0x50,0x10,0x10,0x10,0x10,0x7c},  //1
{0x7E,0x2,0x2,0x7E,0x40,0x40,0x40,0x7E},    //2
{0x3E,0x2,0x2,0x3E,0x2,0x2,0x3E,0x0},       //3
{0x8,0x18,0x28,0x48,0xFE,0x8,0x8,0x8},      //4
{0x3C,0x20,0x20,0x3C,0x4,0x4,0x3C,0x0},     //5
{0x3C,0x20,0x20,0x3C,0x24,0x24,0x3C,0x0},   //6
{0x3E,0x22,0x4,0x8,0x8,0x8,0x8,0x8},        //7
{0x0,0x3E,0x22,0x22,0x3E,0x22,0x22,0x3E},   //8
{0x3E,0x22,0x22,0x3E,0x2,0x2,0x2,0x3E},     //9
{0x18,0x24,0x42,0x42,0x7E,0x42,0x42,0x42},  //A
{0x3C,0x22,0x22,0x3c,0x22,0x22,0x3C,0x0},   //B
{0x3C,0x40,0x40,0x40,0x40,0x40,0x40,0x3C},  //C
{0x7C,0x22,0x22,0x22,0x22,0x22,0x22,0x7C},  //D
{0x7C,0x40,0x40,0x7C,0x40,0x40,0x40,0x7C},  //E
{0x7C,0x40,0x40,0x7C,0x40,0x40,0x40,0x40},  //F
{0x3C,0x40,0x40,0x40,0x4c,0x44,0x44,0x3C},  //G
{0x44,0x44,0x44,0x7C,0x44,0x44,0x44,0x44},  //H
{0x7C,0x10,0x10,0x10,0x10,0x10,0x10,0x7C},  //I
{0x3C,0x8,0x8,0x8,0x8,0x8,0x48,0x30},       //J
{0x0,0x24,0x28,0x30,0x20,0x30,0x28,0x24},   //K
{0x40,0x40,0x40,0x40,0x40,0x40,0x40,0x7C},  //L
{0x81,0xC3,0xA5,0x99,0x81,0x81,0x81,0x81},  //M
{0x0,0x42,0x62,0x52,0x4A,0x46,0x42,0x0},    //N
{0x3C,0x42,0x42,0x42,0x42,0x42,0x42,0x3C},  //O
{0x3C,0x22,0x22,0x22,0x3C,0x20,0x20,0x20},  //P
{0x1C,0x22,0x22,0x22,0x22,0x26,0x22,0x1D},  //Q
{0x3C,0x22,0x22,0x22,0x3C,0x24,0x22,0x21},  //R
{0x0,0x1E,0x20,0x20,0x3E,0x2,0x2,0x3C},     //S
{0x0,0x3E,0x8,0x8,0x8,0x8,0x8,0x8},         //T
{0x42,0x42,0x42,0x42,0x42,0x42,0x22,0x1C},  //U
{0x42,0x42,0x42,0x42,0x42,0x42,0x24,0x18},  //V
{0x0,0x49,0x49,0x49,0x49,0x2A,0x1C,0x0},    //W
{0x0,0x41,0x22,0x14,0x8,0x14,0x22,0x41},    //X
{0x41,0x22,0x14,0x8,0x8,0x8,0x8,0x8},       //Y
{0x0,0x7F,0x2,0x4,0x8,0x10,0x20,0x7F},      //Z
};

static void write_reg(uint8_t reg, uint8_t value)
{
  uint8_t tx_data[2] = {reg, value };
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, GPIO_PIN_RESET);
  HAL_SPI_Transmit(&hspi2, tx_data, sizeof(tx_data),100);
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, GPIO_PIN_SET);
}

static void max7219_init_8x8MAT() {
  write_reg(0x09, 0x00);       //  no decoding
  write_reg(0x0a, 0x03);       //  brightness intensity
  write_reg(0x0b, 0x07);       //  scan limit = 8 LEDs
  write_reg(0x0c, 0x01);       //  power down =0,normal mode = 1
  write_reg(0x0f, 0x00);       //  no test display

}


int main(void)
{
  HAL_Init()
  SystemClock_Config();
  MX_GPIO_Init();
  MX_SPI1_Init();
  MX_SPI2_Init();

  /* USER CODE BEGIN 2 */
  max7219_init_8x8MAT();
  HAL_Delay(10);
  max7219_Init_16SEG(7);
  max7219_Decode_On();
  /* USER CODE END 2 */

  while (1)
  {
    switch(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_0))
    {
        case(GPIO_PIN_SET):
          {
           max7219_PrintItos(DIGIT_8,87654321);
           HAL_Delay(2000);
           max7219_Clean();

           max7219_PrintFtos(DIGIT_8,-3.66,2);
           HAL_Delay(2000);
           max7219_Clean();

           max7219_PrintNtos(DIGIT_8,9999,4);
           HAL_Delay(2000);
           max7219_Clean();

           max7219_PrintNtos(DIGIT_8,9999,8);
           HAL_Delay(2000);
           max7219_Clean();
          }break;
        case(GPIO_PIN_RESET):
           {
              for(int j=0 ; j<38;j++)
              {
                for(int i=1;i<9;i++)
                {
                  write_reg(i,  disp1ay[j][i-1]);
                }
                HAL_Delay(700);
              }
           }break;
}}}