74HC595 之控制原理
影片一
影片二
先前在露天買了四位數七段顯示器，
【程式碼解說】
/*
4-Digit 7-Segment display driver.
2x 74HC595 wired to 2x 4-digit 7-segment displays
bits 0-7 select a digit
bits 8-14 A-G
顯示文字showText('A','B','C','D');
顯示數字showText(1,2,3,4);
若要顯示小數點：該位數字＋10
*/
showText() 函數內可以顯示四位文字與數字
1. 小寫英文字母 => 需用 ' '
2. 大寫英文字母 => 需用 ' '
3. 數字：0,1,2,3,4,5,6,7,8,9
4.小數點
char disp_c[8] ;
const int SCLK_pin=6;
const int RCLK_pin=7;
const int DIO_pin =5;
int disp[8];
//time values for delay workaround
unsigned long prev =0;
unsigned long waitMS=0;
void setup(){
pinMode(RCLK_pin,OUTPUT);
pinMode(DIO_pin,OUTPUT);
pinMode(SCLK_pin,OUTPUT);
showText('O','P','E','N');
}
int n;
unsigned long start=millis();
byte b = 0;
void loop(){
showDisplay();
if(b==0){
b++;
wait(1000);
} else{
if ( millis() > (prev + waitMS)) {
showText((n/1000)%10+10,(n/100)%10,(n/10)%10,n%10);
n++;
if(n>10000) {
n=0;
}
wait(10);
}
}
}
void showText(char a, char b , char c,char d){
disp_c[0] = d;
disp_c[1] = c;
disp_c[2] = b;
disp_c[3] = a;
}
void showDisplay(){
setDisp();
for(int i=0; i<8; i++) {
setDigit(i,disp[i]);
}
}
void setDigit(int dig, int character){
int digits[]= {
128,64,32,16,8,4,2,1 };
//character set (0-9)0-9
// (10-19)0.-9.
// (20-45)A-Z
// (46-71)a-z
// (72)- (73) space
int characters[]= {
3,159,37,13,153,73,65,31,1,9,
2,158,36,12,152,72,64,30,0,8,
17,1,99,3,97,113,67,145,243,135,145,227,85,19,3,49,25,115,73,31,129,129,169,145,137,37,
5,193,229,133,33,113,9,209,247,143,81,227,85,213,197,49,25,245,73,225,199,199,169,145,137,37,
253,255 };
digitalWrite(RCLK_pin, LOW);
shiftOut(DIO_pin, SCLK_pin, LSBFIRST, characters[character]);
shiftOut(DIO_pin, SCLK_pin, LSBFIRST, digits[dig]);
digitalWrite(RCLK_pin, HIGH);
}
void setDisp(){
for (int i=0; i<8;i++) {
int val = disp_c[i];
if((val >= 32)&&(val <= 47)){
switch (val){
case 45 :
val = 72;
break;
default :
val = 73;
break;
}
} else if((val >= 48)&&(val <= 57)){ //0-9
val -= 48;
}
else if((val >= 65)&&(val <= 90)){ //A-Z
val -= 45;
}
else if((val >= 97)&&(val <= 122)){ //a-z
val -= 51;
}
disp[i] = val;
}
}
void wait( unsigned long milsec){
prev = millis();
waitMS = milsec;
}
控制碼2
const int RCLK = 7; //RCLK
const int SCLK = 6; //SCLK
const int DIO = 5; //DIO
byte value[] ={ B11000000, // 0
B11111001, // 1
B10100100, // 2
B10110000, // 3
B10011001, // 4
B10010010, // 5
B10000010, // 6
B11111000, // 7
B10000000, // 8
B10010000, // 9
B01000000, // 0.
B01111001, // 1.
B00100100, // 2.
B00110000, // 3.
B00011001, // 4.
B00010010, // 5.
B00000010, // 6.
B01111000, // 7.
B00000000, // 8.
B00010000, // 9.
B10111111, // -
B11111111};// display nothing
byte digit[] ={ B00000000,
B00000001, // left segment
B00000010,
B00000100,
B00001000,
B00010000,
B00100000,
B01000000,
B10000000}; // right segment
void setup() {
Serial.begin(9600);
pinMode(SCLK, OUTPUT);
pinMode(RCLK, OUTPUT);
pinMode(DIO, OUTPUT);
}
void loop(){
sign(1);
disp(2,15);
disp(3,6);
}
void disp(int d , int num ){ //透過本動作函數 disp( 位數， 數字 ); 依序顯示
digitalWrite(RCLK,LOW);
shiftOut(DIO,SCLK,MSBFIRST,B11111111); // select all segments
shiftOut(DIO,SCLK,MSBFIRST,B11111111); // display nothing
digitalWrite(RCLK,HIGH);
digitalWrite(RCLK,LOW);
// select the fourth segment from left
shiftOut(DIO,SCLK,MSBFIRST,value[num]);
shiftOut(DIO,SCLK,MSBFIRST,digit[5-d]);
digitalWrite(RCLK,HIGH);
}
void sign(int d ){ //透過本動作函數 sign( 位數 ) ; 加上負號
digitalWrite(RCLK,LOW);
shiftOut(DIO,SCLK,MSBFIRST,B11111111); // select all segments
shiftOut(DIO,SCLK,MSBFIRST,B11111111); // display nothing
digitalWrite(RCLK,HIGH);
digitalWrite(RCLK,LOW);
// select the fourth segment from left
shiftOut(DIO,SCLK,MSBFIRST,value[20]);
shiftOut(DIO,SCLK,MSBFIRST,digit[5-d]);
digitalWrite(RCLK,HIGH);
}
showText('A','B','C','D')
showText(千,百,十,個)
ex: 無小數點 顯示 0~9999
int num[5];
showText(num[0],num[1],num[2],num[3])
num[0]=x/1000 ;
num[1]=x%1000/100;
num[2]=x%100/10;
num[3]=x%10;
ex: 無小數點 顯示 0.00~99.99
int x=x*100;
int num[5];
showText(num[0],num[1],num[2],num[3])
num[0]=x/1000 ;
num[1]=x%1000/100+10;
num[2]=x%100/10;
num[3]=x%10;
SCLK 插在 D6
RCLK 插在 D7
DIO 插在 D5