Instructables

74HC595 digital LED Display Based on Arduino( Code Provided)

Picture of 74HC595 digital LED Display Based on Arduino( Code Provided)
The Chief Engineer of  ICStation R&D department Jack is using ICStation UNO R3 compatible with Arduino to successfully make the 74HC595 drive four digital LED display. We will share the schematic diagram, wiring diagram,making steps,download Diagram and  also the useful program code designed by ICStation.


When you develop a project, it often needs to make IO expansion.The 74HC595 shifting register is a good choice. Following will introduce you that use two pieces 74HC595 to realize the display system of four digital LED(of course, can also realize 8 digital LED display) .It only uses three IO (PIN2,3, 5) of Arduino.


Components list:
1. ICStation UNO development board  $12.69 ( Or Arduino UNO development board)
2.2PCS 74HC595
3.DuPont line: 30PCS
4.four digital LED display with the same anode
5. 20 PCS 20mm pin header
6.Bread board
7.USB Cable
8.4PCS 47Ω resistance
 
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Step 1: Schematic diagram

Picture of Schematic diagram

Step 2: The wiring diagram:

Picture of The wiring diagram:

Step 3: To build the circuit according to the schematic diagram

Picture of To build the circuit according to the schematic diagram
Because we only do testing, maybe it is not practical.If you want it to have practical use, you should weld it manually which will make the circuit more stable. When you build the circuit by hand the pin header is needed which will help you to change the DuPont line to jumper wires immediately.

Step 4: Download Diagram

Picture of Download Diagram
dancopy23 days ago

Hi Friend! the following error appears:
'sclr' was not declared in this scope
Thank you

dqxt4 months ago

the code 'pinMode(sclr, OUTPUT); ' must be commented.

it is better to use 'ShitOut()' function.

ICStation (author)  dqxt4 months ago

Thank you for your valuable advice!

The following is the code that has been changed.

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#define HC_DATA_H digitalWrite(data, HIGH) // data line output high
#define HC_DATA_L digitalWrite(data, LOW) //date line output low
#define HC_RCK_H digitalWrite(rck, HIGH) // rck output high
#define HC_RCK_L digitalWrite(rck, LOW) // rck output low
#define HC_SCK_H digitalWrite(sck, HIGH) // sck output high
#define HC_SCK_L digitalWrite(sck, LOW) // sck output low



unsigned char LED_BCD[16] ={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e }; //common anode digital tube BCD code
//Define the pin
int data =2;
int rck =3;
int sck =5;
// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(data, OUTPUT); //initial data
pinMode(rck, OUTPUT); //initial rck
pinMode(sck, OUTPUT); //initial sck
pinMode(sclr, OUTPUT); //initial sclr


}

// the loop routine runs over and over again forever:
void loop() {

unsigned char dopp =0;
for( unsigned char i=0; i < 4; ++i)
{
if(i ==3) dopp =1;
else dopp =0;
LED_display(i,i,dopp); //Nixie Tube display
}



}

void LED_display(char LED_number,unsigned char LED_display,unsigned char LED_dp)
{
// data analyse
unsigned int hc_disp = 0,hc_ledcode,hc_ledcode_temp=0;

if(LED_display > 15) LED_display = 0;
hc_ledcode = LED_BCD[LED_display] ; //get BCD code
for(unsigned char i=0; i < 8;++i)
{
hc_ledcode_temp <<=1;
if(hc_ledcode&0x01) hc_ledcode_temp |= 0x01;
hc_ledcode >>=1;

}
if(LED_dp) hc_ledcode_temp &= 0xfe;
hc_disp = hc_ledcode_temp;

switch(LED_number)
{
case 0: hc_disp |= 0x8000;break;
case 1: hc_disp |= 0x4000;break;
case 2: hc_disp |= 0x2000;break;
case 3: hc_disp |= 0x1000;break;
}

write_74HC595_ShiftOUTPUT(hc_disp); //74HC595 shifting register data transfer


}

//shift output to 74HC595
void write_74HC595_ShiftOUTPUT( unsigned int data_a) //communication with 74HC595
{
char look =0;
HC_RCK_L; //latch open
HC_SCK_L;



for (;look < 16; ++look)
{
if(data_a&0x0001) {HC_DATA_H;}
else {HC_DATA_L;}
HC_SCK_H;

HC_SCK_L;
data_a >>= 1;
}
HC_RCK_H;
}

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