TM1637.cpp

//  Author: avishorp@gmail.com
//
//  This library is free software; you can redistribute it and/or
//  modify it under the terms of the GNU Lesser General Public
//  License as published by the Free Software Foundation; either
//  version 2.1 of the License, or (at your option) any later version.
//
//  This library is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
//  Lesser General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public
//  License along with this library; if not, write to the Free Software
//  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
//

extern "C" {
  #include <stdlib.h>
  #include <string.h>
  #include <inttypes.h>
}

#include <TM1637.h>
#include <Arduino.h>


TM1637::TM1637(uint8_t pinClk, uint8_t pinDIO)
{
      // Copy the pin numbers
      m_pinClk = pinClk;
      m_pinDIO = pinDIO;
      	
      // Set colon off by default? Or change the constructor?
      m_colon = false;
      	
      // Set the pin direction and default value.
      // Both pins are set as inputs, allowing the pull-up resistors to pull them up
      pinMode(m_pinClk, INPUT);
      pinMode(m_pinDIO,INPUT);
      digitalWrite(m_pinClk, LOW);
      digitalWrite(m_pinDIO, LOW);
}


void TM1637::setBrightness(uint8_t brightness)
{
  m_brightness = brightness;
}


void TM1637::setColon(bool colon)
{
  m_colon = colon;
}


void TM1637::setSegments(const uint8_t segments[], uint8_t length, uint8_t pos)
{
    // Write COMM1
	start();
	writeByte(TM1637_I2C_COMM1);
	stop();
	
	// Write COMM2 + first digit address
	start();
	writeByte(TM1637_I2C_COMM2 + (pos & 0x03));
	
	// Write the data bytes
	for (uint8_t k=0; k < length; k++) 
	 writeByte(segments[k]);
	  
	stop();

	// Write COMM3 + brightness
	start();
	writeByte(TM1637_I2C_COMM3 + (m_brightness & 0x0f));
	stop();
}
 

void TM1637::showNumberDec(int num, bool leading_zero, uint8_t length, uint8_t pos)
{
	uint8_t digits[4];
	const static int divisors[] = { 1, 10, 100, 1000 };
	bool leading = true;
	
	for(int8_t k = 0; k < 4; k++) {
	  int divisor = divisors[4 - 1 - k];
	  int d = num / divisor;
	  
          if (d == 0) {
		  if (leading_zero || !leading || (k == 3))
		    digits[k] = encodeDigit(d);
	          else
		    digits[k] = 0;
		  }
		else {
		  digits[k] = encodeDigit(d);
		  num -= d * divisor;
		  leading = false;
		}
	  }
	
	if(m_colon)  digits[COLON_POSITION] |= 0x80;
	
	setSegments(digits + (4 - length), length, pos);
}


void TM1637::bitDelay()
{
	delayMicroseconds(50);
}
   

void TM1637::start()
{
  pinMode(m_pinDIO, OUTPUT);
  bitDelay();
}
   

void TM1637::stop()
{
	pinMode(m_pinDIO, OUTPUT);
	bitDelay();
	pinMode(m_pinClk, INPUT);
	bitDelay();
	pinMode(m_pinDIO, INPUT);
	bitDelay();
}
  
bool TM1637::writeByte(uint8_t b)
{
  uint8_t data = b;

  // 8 Data Bits
  for(uint8_t i = 0; i < 8; i++) {
    // CLK low
    pinMode(m_pinClk, OUTPUT);
    bitDelay();
    
    // Set data bit
    if (data & 0x01)
      pinMode(m_pinDIO, INPUT);
    else
      pinMode(m_pinDIO, OUTPUT);
    
    bitDelay();
	
    // CLK high
    pinMode(m_pinClk, INPUT);
    bitDelay();
    data = data >> 1;
  }
  
  // Wait for acknowledge
  // CLK to zero
  pinMode(m_pinClk, OUTPUT);
  pinMode(m_pinDIO, INPUT);
  bitDelay();
  
  // CLK to high
  pinMode(m_pinClk, INPUT);
  bitDelay();
  uint8_t ack = digitalRead(m_pinDIO);
  if (ack == 0)
    pinMode(m_pinDIO, OUTPUT);
  bitDelay();
  pinMode(m_pinClk, OUTPUT);
  bitDelay();
  return ack;
}


uint8_t TM1637::encodeDigit(uint8_t digit)
{
	return digitToSegment[digit & 0x0f];
}

void TM1637::clear(void)
{
  uint8_t data[] = { 0,0,0,0 };
  setSegments(data);

}