#include <Arduino.h>

const uint8_t CLK_CYCLE_DELAY = 100;// us
const uint8_t CLK_PIN = 3;
const uint8_t DIO_PIN = 2;
const uint8_t NUM_DIGITS = 4;

uint8_t buffer[NUM_DIGITS+1] = {0xC0, 0x07, 0x07, 0x07, 0x07}; // first byte will be the register address
// LED segment patterns.
const uint8_t NUM_PATTERNS = 10;
const uint8_t PATTERNS[NUM_PATTERNS] = {
  0x3F, // 0
  0x06, // 1
  0x5B, // 2
  0x4F, // 3
  0x66, // 4
  0x6D, // 5
  0x7D, // 6
  0x07, // 7
  0x7F, // 8
  0x6F, // 9
};

void setDataPin(uint8_t _bit){
  digitalWrite(DIO_PIN,_bit);
}
void setClkPint(uint8_t _bit){
  digitalWrite(CLK_PIN,_bit);
}

void sleep(int sleep){
  delayMicroseconds(sleep);
}

void start() {
    setDataPin(0);
    sleep(CLK_CYCLE_DELAY);
    setClkPint(0);
    sleep(CLK_CYCLE_DELAY);
}

void stop() {
    setDataPin(0);
    sleep(CLK_CYCLE_DELAY);
    setClkPint(1);
    sleep(CLK_CYCLE_DELAY);
    setDataPin(1);
}
    

void writeByte(uint8_t _byte){
    for(uint8_t i=0;i<8;i++){
      setDataPin(_byte >> i & 0x01) ;
      sleep(CLK_CYCLE_DELAY);
      setClkPint(1);
      sleep(CLK_CYCLE_DELAY);
      setClkPint(0);
      sleep(CLK_CYCLE_DELAY);
    }
      
    setClkPint(0);
    sleep(CLK_CYCLE_DELAY);
    setClkPint(1);
    sleep(CLK_CYCLE_DELAY);
    setClkPint(0);
    sleep(CLK_CYCLE_DELAY);
}

void writeDataCmd(uint8_t cmd){
    start();
    writeByte(cmd);
    stop();
}

void sendByteStream(uint8_t *bytes,uint8_t len) {
    writeDataCmd(0x40);
    start();
    for(uint8_t i=0;i<len;i++){
        writeByte(bytes[i]);
    }
    stop();
}

void displayCount(int count){
  for(uint8_t i=0;i<NUM_DIGITS;i++){
    uint8_t digit = count % 10;
    count = count/10;
    buffer[NUM_DIGITS - i] = PATTERNS[digit];
  } 
  sendByteStream(buffer,NUM_DIGITS+1);
}

void setup() {
  Serial.begin(115200);
  Serial.println("TM1637 Demo");
  pinMode(CLK_PIN,OUTPUT);
  pinMode(DIO_PIN,OUTPUT);
  stop();
  // switch on the display
  //uint8_t displayControlCmd[1]={0x8F};// display on with full brightness
  //sendByteStream(displayControlCmd,1);

  //sendByteStream(buffer, 5);

  start();
  writeByte(0x40);
  stop();
  start();
  writeByte(0x8F);
  stop();

  start();
  writeByte(0x40);
  stop();
  start();
  writeByte(0xC0);
  writeByte(0x07);
  writeByte(0x07);
  writeByte(0x07);
  writeByte(0x07);
  stop();
}

void loop() {  
  //displayCount(millis()/1000);
  //delay(100);
}