Freenove Ultimate Starter Kit - Page 183

183
Chapter 17 74HC595 & LEDBar Graph
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Code
In this project, make a flowing water light with 74HC595 to learn its usage.
C Code 17.1.1 LightWater02
First observe the project result, and then analyze the code.
1. Use cd command to enter 17.1.1_LightWater02 directory of C code.
cd ~/Freenove_Ultimate_Starter_Kit_for_Raspberry_Pi/Code/C_Code/17.1.1_LightWater02
2. Use following command to compile “LightWater02.c” and generate executable file “LightWater02”.
gcc LightWater02.c -o LightWater02 -lwiringPi
3. Then run the generated file “LightWater02”.
sudo ./LightWater02
After the program is executed, LEDBar Graph begin to display flowing water light from left to right, then from
right to left.
The following is the program code:
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#include <wiringPi.h>
#include <stdio.h>
#include <wiringShift.h>
#define dataPin 0 //DS Pin of 74HC595(Pin14)
#define latchPin 2 //ST_CP Pin of 74HC595(Pin12)
#define clockPin 3 //SH_CP Pin of 74HC595(Pin11)
void _shiftOut(int dPin,int cPin,int order,int val){
int i;
for(i = 0; i < 8; i++ ){
digitalWrite(cPin,LOW);
if(order == LSBFIRST){
digitalWrite(dPin,((0x01&(val>>i)) == 0x01) ? HIGH : LOW);
delayMicroseconds(10);
}
else {//if(order == MSBFIRST){
digitalWrite(dPin,((0x80&(val<<i)) == 0x80) ? HIGH : LOW);
delayMicroseconds(10);
}
digitalWrite(cPin,HIGH);
delayMicroseconds(10);
}
}
int main( void)
{
int i;
unsigned char x;