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  • STC89C52驱动MAX7219LED点阵级联, 文字滚动效果

    级联下的传值方式

    级联下, N个MAX7219相当于组成了一个8*N bit宽度的锁存器, 如果需要对第M个7219进行写入, 需要做M次寻址+写入后拉高CS, 才能到达这个7219. 如果仅仅对这个7219进行操作, 不操作其他7219, 那么在第1个寻址写入后, 做的寻址写入输入的都是空值.

    对于级联的MAX7219, 如果要显示产生滚动的效果, 那么每次要操作的都是整行, 可以将其看成是一个(N8)8的点阵, 每次直接对一行写入N个byte.

    连线

    • CLK => P2.2
    • CS => P2.1
    • DIN => P2.0
    • VCC => 5V
    • GND => GND

    代码示例

    #include <reg52.h>
    #include <intrins.h>
    
    #define u8 unsigned char
    #define u16  unsigned int
    
    #define DECODE_MODE  0x09
    #define INTENSITY    0x0A
    #define SCAN_LIMIT   0x0B
    #define SHUT_DOWN    0x0C
    #define DISPLAY_TEST 0x0F
    
    #define BLOCKS 4
    
    sbit MAX7219_CLK = P2^2;
    sbit MAX7219_CS  = P2^1;
    sbit MAX7219_DIN = P2^0;
    
    u8 code bytes[] = {
      0x3e,0x63,0x63,0x7f,0x63,0x63,0x63,0x63, //A
      0x7e,0x63,0x63,0x7e,0x63,0x63,0x63,0x7e, //B
      0x3e,0x63,0x63,0x60,0x60,0x63,0x63,0x3e, //C
      0x3e,0x63,0x73,0x6b,0x67,0x63,0x63,0x3e, //0
      0x0c,0x1c,0x3c,0x0c,0x0c,0x0c,0x0c,0x3f, //1
      0x3e,0x63,0x63,0x06,0x0c,0x18,0x30,0x7f, //2
      0x3e,0x63,0x63,0x0e,0x03,0x63,0x63,0x3e, //3
      0x06,0x0e,0x1e,0x36,0x66,0x7f,0x06,0x06, //4
      0x7f,0x60,0x60,0x7e,0x03,0x03,0x03,0x7e, //5
      0x3e,0x63,0x60,0x7e,0x63,0x63,0x63,0x3e, //6
      0x7f,0x03,0x03,0x06,0x0c,0x18,0x18,0x18, //7
      0x3e,0x63,0x63,0x3e,0x63,0x63,0x63,0x3e, //8
      0x3e,0x63,0x63,0x63,0x3f,0x03,0x63,0x3e, //9
    };
    
    u8 val[BLOCKS];
    u8 character_len = sizeof(bytes) / 8;
    
    void delay(u16 x)
    {
      u16 i,j;
      for(i = 0; i < x; i++)
        for(j = 0;j < 112; j++);
    }
    
    void Max7219_writeByte(u8 dat)
    {
      u8 i;
      MAX7219_CS = 0;
      for(i = 8; i >= 1; i--)
      {
        MAX7219_CLK = 0;
        MAX7219_DIN = dat & 0x80; // &10000000, 取最高位
        dat = dat << 1;
        MAX7219_CLK = 1;
      }
    }
    
    void Max7219_singeWrite(u8 index, u8 addr, u8 dat)
    { 
      MAX7219_CS = 0;
      Max7219_writeByte(addr);
      Max7219_writeByte(dat);
      while(index--)
      {
        Max7219_writeByte(0x00);
        Max7219_writeByte(0x00);
      }
      MAX7219_CS = 1;
    }
    
    void Max7219_multiWrite(u8 addr, u8 len, u8* dat)
    { 
      MAX7219_CS = 0;
      while(len--)
      {
        Max7219_writeByte(addr);
        Max7219_writeByte(*dat++);
      }
      MAX7219_CS = 1;
    }
    
    void Max7219_init(void)
    {
      u8 i;
      for (i = 0; i < BLOCKS; i++)
      {
        Max7219_singeWrite(i, SHUT_DOWN,   0x01);  // 0x00:shutdown, 0x01:normal
        Max7219_singeWrite(i, DECODE_MODE, 0x00);  // No decode
        Max7219_singeWrite(i, INTENSITY,   0x03);  // 0x00:min, 0x0F:max
        Max7219_singeWrite(i, SCAN_LIMIT,  0x07);  // Display 8 digits
        Max7219_singeWrite(i, DISPLAY_TEST, 0x00); // 0x00:normal, 0x01:test mode
      }
    }
    
    void main(void)
    {
      // pos:点阵右沿对应的val数组元素编号. 因为要无缝滚屏, 用右沿做求余不会产生跳变
      // lpos: 点阵左沿对应的val数组元素编号, 每次根据点阵右沿和点阵宽度计算得到
      u16 pos = 0, lpos = 0;
      // cpos: 点阵左沿对应的文字编号
      // bpos: 在这个文字中, 当前移动到第几个bit, 值从0-7
      u8 i, j, cpos = 0, bpos = 0, tcpos = 0;
      Max7219_init();
      while(1)
      {
        lpos = pos + sizeof(bytes) - BLOCKS * 8;
        cpos = lpos / 8; // 第几个字
        bpos = lpos % 8; // 字的第几个bit
        for (i = 0; i < 8; i++) // 对每一行, 对val的每个元素赋值
        {
          // 从第cpos个字的bpos位开始, 填满每个点阵对应的byte
          for (j = 0; j < BLOCKS; j++)
          {
            // 高位部分
            tcpos = (cpos + j) % character_len;
            val[j] = bytes[tcpos * 8 + i] << bpos;
            // 低位部分
            tcpos = (cpos + j + 1) % character_len;
            val[j] |= bytes[tcpos * 8 + i] >> (8 - bpos);
          }
          Max7219_multiWrite(i+1, BLOCKS, val);
        }
        // 每处理完一屏, pos右移一位
        pos = (pos + 1) % sizeof(bytes);
        delay(50);
      }
    }
    

    参考

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  • 原文地址:https://www.cnblogs.com/milton/p/15201085.html
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