Lesson 27--Microduino 8*8 Lattice Static Display

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Objective

The tutorial will teach you use two 74HC595 to control 8** lattice and display a static smiling faces.

Equipment


8*8 lattice LED introduction: 8*8 lattice LED is made of 64 light-emitting diodes, different type has different definition of the pin. This example uses the LD-1088BS 8*8 lattice LED, the pins are defined as follows:

第二十七课-Microduino 8 8点阵引脚定义.jpg

Schematic

第二十七课-Microduino 8 8点阵静态显示原理图.jpg


Pin Table:

Lattice ROW Lattice 16pin 74HC595 74HC595
1 13 15 Q0
2 3 1 Q1
3 4 2 Q2
4 10 3 Q3
5 6 4 Q4
6 11 5 Q5
7 15 6 Q6
8 16 7 Q7
Lattice COL Lattice 16pin 74HC595 74HC595
1 5 15 Q0
2 2 1 Q1
3 7 2 Q2
4 1 3 Q3
5 12 4 Q4
6 8 5 Q5
7 14 6 Q6
8 9 7 Q7

Program

    //Pin connects to 74HC595的ST_CP
    int latchPin = 8;
    //Pin connects to 74HC595的SH_CP
    int clockPin = 12;
    ////Pin connects to 74HC595的DS
    int dataPin = 11;
     
     
     
    void setup() {
      //Set barud roate 9600   
      Serial.begin(9600);
      //Set the latchpin as output
      pinMode(latchPin, OUTPUT);
     
    }
     
    void loop() {
      //Smile for 8x8 Matrix LED
      digitalWrite(latchPin, 0);
      shiftOut(dataPin, clockPin, B01111111);  //col
      shiftOut(dataPin, clockPin, B00111100);  //row
      digitalWrite(latchPin, 1);
     
      digitalWrite(latchPin, 0);
      shiftOut(dataPin, clockPin, B10111111);  //col
      shiftOut(dataPin, clockPin, B01000010);  //row
      digitalWrite(latchPin, 1);
     
      digitalWrite(latchPin, 0);
      shiftOut(dataPin, clockPin, B11011111);  //col
      shiftOut(dataPin, clockPin, B10100101);  //row
      digitalWrite(latchPin, 1);
     
      digitalWrite(latchPin, 0);
      shiftOut(dataPin, clockPin, B11101111);  //col
      shiftOut(dataPin, clockPin, B10000001);  //row
      digitalWrite(latchPin, 1);
     
      digitalWrite(latchPin, 0);
      shiftOut(dataPin, clockPin, B11110111);  //col
      shiftOut(dataPin, clockPin, B10100101);  //row
      digitalWrite(latchPin, 1);
     
      digitalWrite(latchPin, 0);
      shiftOut(dataPin, clockPin, B11111011);  //col
      shiftOut(dataPin, clockPin, B10011001);  //row
      digitalWrite(latchPin, 1);
     
      digitalWrite(latchPin, 0);
      shiftOut(dataPin, clockPin, B11111101);  //col)
      shiftOut(dataPin, clockPin, B01000010);  //row
      digitalWrite(latchPin, 1);
     
      digitalWrite(latchPin, 0);
      shiftOut(dataPin, clockPin, B11111110);  //col
      shiftOut(dataPin, clockPin, B00111100);  //row
      digitalWrite(latchPin, 1);
     
     
    }
     
    void shiftOut(int myDataPin, int myClockPin, byte myDataOut) {
     
      //initialization
      int i=0;
      int pinState;
      pinMode(myClockPin, OUTPUT);
      pinMode(myDataPin, OUTPUT);
     
      //clear everything out just in case to
      //prepare shift register for bit shifting
      digitalWrite(myDataPin, 0);
      digitalWrite(myClockPin, 0);
     
      //for each bit in the byte myDataOut�
      //NOTICE THAT WE ARE COUNTING DOWN in our for loop
      //This means that %00000001 or "1" will go through such
      //that it will be pin Q0 that lights.
      for (i=7; i>=0; i--)  {
        digitalWrite(myClockPin, 0);
     
        //if the value passed to myDataOut and a bitmask result
        // true then... so if we are at i=6 and our value is
        // %11010100 it would the code compares it to %01000000
        // and proceeds to set pinState to 1.
        if ( myDataOut & (1<<i) ) {
          pinState= 1;
        }
        else {       
          pinState= 0;
        }
     
        //Sets the pin to HIGH or LOW depending on pinState
        digitalWrite(myDataPin, pinState);
        //register shifts bits on upstroke of clock pin  
        digitalWrite(myClockPin, 1);
        //zero the data pin after shift to prevent bleed through
        digitalWrite(myDataPin, 0);
      }
     
      //stop shifting
      digitalWrite(myClockPin, 0);
    }

Debug

Step 1: Copy the code to IDE and compile it

Step 2: Set up circuit, as follows:

第二十七课-Microduino 8 8点阵静态显示连接图.jpg

In order to protect the circuit, plus a 220Ω resistor on the every connection line (total 8 lines) between one 74HC595 chip and 8*8 lattice LED. In our example, we don't use the resistor, so the LED's brightness is strong. If the lattice's quality is bad and easily broken.

Step 3: Run program

Result

8*8 lattice LED will display a smiling face.

Video