4-Digit Seven Segment TM1637 Display interfacing with arduino

Hello Arduino Lovers,

In this post, I am going to interface 4-digit seven segment display with arduino. It's TM1637 based display and it just requires 4-pins. And it's better than conventional 4-digid SSD since that requires 12 (8+4) output pins. So, it saves our pin. As MCU have limited I/Os it's very useful.

The pins are as follows:

CLK, DIO, VCC and GND. 

It's 2-wire serial communication and it's different from I2C communication.

4-Digit SSD

The connections are as follows:

Display                             Arduino

CLK                                 Pin no. 2

DIO                                  Pin no. 3

VCC                                 +5 V

GND                                GND

In order, to send proper data, we have pass start commands , then data and finally stop commands. We are using functions for each of them.

Source Code:

/*

Program for displaying counting from 0-9999

www.funwidelectronics.blogspot.in

This source code is modified from:

https://blog.3d-logic.com/2015/01/21/arduino-and-the-tm1637-4-digit-seven-segment-display/

Thanks for the code

*/

// Module connection pins (Digital Pins)

#define clk 2

#define data 3

uint8_t digits[] = { 0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f };

void setup()

{

pinMode(clk, OUTPUT);

pinMode(data, OUTPUT);

start();

writeValue(0x8f);   // for changing the brightness (0x88-DIM     0x8f-Bright)

stop();

// clear display

//write(0x06, 0x5b, 0x4f, 0x00);

}

void loop()

{

for(int j=0;j<10000;j++)

  {

    write(digits[j/1000], digits[(j%1000)/100], digits[((j%1000)%100)/10], digits[j%10]);

    delayMicroseconds(50);

  }

}

void start(void)

{

digitalWrite(clk,HIGH);//send start signal to TM1637

digitalWrite(data,HIGH);

delayMicroseconds(5);

digitalWrite(data,LOW);

digitalWrite(clk,LOW);

delayMicroseconds(5);

}

void stop(void)

{

digitalWrite(clk,LOW);

digitalWrite(data,LOW);

delayMicroseconds(5);

digitalWrite(clk,HIGH);

digitalWrite(data,HIGH);

delayMicroseconds(5);

}

void write(uint8_t first, uint8_t second, uint8_t third, uint8_t fourth)

{

start();

writeValue(0x40);

stop();

start();

writeValue(0xc0);

writeValue(first);

writeValue(second);

writeValue(third);

writeValue(fourth);

stop();

}

bool writeValue(uint8_t value)

{

for(uint8_t i = 0; i < 8; i++)

{

digitalWrite(clk, LOW);

delayMicroseconds(5);

digitalWrite(data, (value & (1 << i)) >> i);

delayMicroseconds(5);

digitalWrite(clk, HIGH);

delayMicroseconds(5);

}

// wait for ACK

digitalWrite(clk,LOW);

delayMicroseconds(5);

pinMode(data,INPUT);

digitalWrite(clk,HIGH);

delayMicroseconds(5);

bool ack = digitalRead(data) == 0;

pinMode(data,OUTPUT);

return ack;

}