TM1637Display.cpp

//  Author: avishorp@gmail.com
//  Extended to 6 digits and key-scan: Guido Dampf
//
//  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 <TM1637Display.h>
#include <Arduino.h>

#define TM1637_I2C_COMM1    0x40
#define TM1637_I2C_COMM2    0xC0
#define TM1637_I2C_COMM3    0x80
#define TM1637_I2C_COMM4    0x42

//
//      A
//     ---
//  F |   | B
//     -G-
//  E |   | C
//     ---
//      D
const uint8_t digitToSegment[] = {
  // XGFEDCBA
  0b00111111,    // 0
  0b00000110,    // 1
  0b01011011,    // 2
  0b01001111,    // 3
  0b01100110,    // 4
  0b01101101,    // 5
  0b01111101,    // 6
  0b00000111,    // 7
  0b01111111,    // 8
  0b01101111,    // 9
  0b01110111,    // A
  0b01111100,    // b
  0b00111001,    // C
  0b01011110,    // d
  0b01111001,    // E
  0b01110001     // F
};

static const uint8_t minusSegments = 0b01000000;

TM1637Display::TM1637Display(uint8_t pinClk, uint8_t pinDIO, unsigned int bitDelay, uint8_t noDigits)
{
  // Copy the pin numbers
  m_pinClk = pinClk;
  m_pinDIO = pinDIO;
  m_bitDelay = bitDelay;
  m_noDigits = noDigits;

  // 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 TM1637Display::setBrightness(uint8_t brightness, bool on)
{
  m_brightness = (brightness & 0x7) | (on? 0x08 : 0x00);
}

void TM1637Display::setSegments(const uint8_t segments[], uint8_t length, uint8_t pos)
{
  if (length==0) length = m_noDigits;
  // Write COMM1
  start();
  if (writeByte(TM1637_I2C_COMM1))
  {
    stop();
    return;
  }
  stop();

  // Write COMM2 + first digit address
  start();
  if (pos > 5) pos &= 0x03;
  if (writeByte(TM1637_I2C_COMM2 + pos))
  {
    stop();
    return;
  }

  // Write the data bytes
  for (uint8_t k=0; k < length; k++)
    if(writeByte(segments[k]))
    {
      stop();
      return;
    }
  stop();

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

  // Write COMM4
  start();
  if (writeByte(TM1637_I2C_COMM4))
  {
    stop();
    return;
  }
  m_KeyCode = readByte();
  stop();
}

void TM1637Display::clear()
{
  uint8_t data[] = { 0, 0, 0, 0, 0, 0 };
  setSegments(data);
}

void TM1637Display::showNumberDec(long num, bool leading_zero, uint8_t length, uint8_t pos)
{
  if (length==0) length = m_noDigits;
  showNumberDecEx(num, 0, leading_zero, length, pos);
}

void TM1637Display::showNumberDecEx(long num, uint8_t dots, bool leading_zero,
                                    uint8_t length, uint8_t pos)
{
  if (length==0) length = m_noDigits;
  showNumberBaseEx(num < 0? -10 : 10, num < 0? -num : num, dots, leading_zero, length, pos);
}

void TM1637Display::showNumberHexEx(uint16_t num, uint8_t dots, bool leading_zero,
                                    uint8_t length, uint8_t pos)
{
  if (length==0) length = m_noDigits;
  showNumberBaseEx(16, num, dots, leading_zero, length, pos);
}

void TM1637Display::showNumberBaseEx(int8_t base, uint32_t num, uint8_t dots, bool leading_zero,
                                     uint8_t length, uint8_t pos)
{
  if (length==0) length = m_noDigits;
  bool negative = false;
  if (base < 0) {
    base = -base;
    negative = true;
  }


  uint8_t digits[6];

  if (num == 0 && !leading_zero) {
    // Singular case - take care separately
    for(uint8_t i = 0; i < (length-1); i++)
      digits[i] = 0;
    digits[length-1] = encodeDigit(0);
  }
  else {
    //uint8_t i = length-1;
    //if (negative) {
    //  // Negative number, show the minus sign
    //    digits[i] = minusSegments;
    //  i--;
    //}

    for(int i = length-1; i >= 0; --i)
    {
      uint8_t digit = num % base;

      if (digit == 0 && num == 0 && leading_zero == false)
        // Leading zero is blank
        digits[i] = 0;
      else
        digits[i] = encodeDigit(digit);

      if (digit == 0 && num == 0 && negative) {
        digits[i] = minusSegments;
        negative = false;
      }

      num /= base;
    }

    if(dots != 0)
    {
      showDots(dots, digits);
    }
  }
  setSegments(digits, length, pos);
}

void TM1637Display::bitDelay()
{
  delayMicroseconds(m_bitDelay);
}

void TM1637Display::start()
{
  pinMode(m_pinDIO, OUTPUT);
  bitDelay();
}

void TM1637Display::stop()
{
  pinMode(m_pinDIO, OUTPUT);
  bitDelay();
  pinMode(m_pinClk, OUTPUT);
  bitDelay();
  bitDelay();
  pinMode(m_pinClk, INPUT);
  bitDelay();
  bitDelay();
  pinMode(m_pinDIO, INPUT);
  bitDelay();
}

bool TM1637Display::writeByte(uint8_t b)
{
  uint8_t data = b;

  // 8 Data Bits
  for(uint8_t i = 0; i < 8; i++) {
    bitDelay();
    // 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 (Cycle 9)
  // CLK to zero
  pinMode(m_pinClk, OUTPUT);
  bitDelay();
  pinMode(m_pinDIO, INPUT);
  bitDelay();

  // CLK to high
  pinMode(m_pinClk, INPUT);
  uint8_t ack = digitalRead(m_pinDIO);
  bitDelay();
  bitDelay();

  return ack; // (Cycle 9 finished)
}

void TM1637Display::showDots(uint8_t dots, uint8_t* digits)
{
  for(int i = 0; i < m_noDigits; ++i)
  {
    digits[i] |= (dots & 0x80);
    dots <<= 1;
  }
}

uint8_t TM1637Display::encodeDigit(uint8_t digit)
{
  return digitToSegment[digit & 0x0f];
}

uint8_t TM1637Display::readByte()
{
  uint8_t b = 0;
  pinMode(m_pinDIO, INPUT);
  for(uint8_t i=0; i<8; i++)
  {
    pinMode(m_pinClk, OUTPUT);
    bitDelay();
    bitDelay();
    pinMode(m_pinClk, INPUT);
    bitDelay();    
    b = (b << 1) | (digitalRead(m_pinDIO)==LOW?0:1);
    bitDelay();    
  }

  // Wait for acknowledge (Cycle 9)
  // CLK to zero
  pinMode(m_pinClk, OUTPUT);
  bitDelay();
  bitDelay();

  // CLK to high
  pinMode(m_pinClk, INPUT);
  uint8_t ack = digitalRead(m_pinDIO);
  bitDelay();
  bitDelay();

  if (ack != 0) return 0xFF;
  return b;
}

uint8_t key(uint8_t code)
{
  if (code == 0xff) return 0;
  return (code >> 4) + 1;
}

uint8_t TM1637Display::lastKeyCode()
{
  return key(m_KeyCode);
}

uint8_t TM1637Display::getKeyCode()
{
  start();
  if (writeByte(TM1637_I2C_COMM4))
  {
    stop();
    return 0;;
  }
  m_KeyCode = readByte();
  stop();
  return key(m_KeyCode);
}