lcd1602_driver.rb

module RubyLcd
  
  class << self 
    def driver 
      Lcd1602Driver.init unless Lcd1602Driver.initialized?
      Lcd1602Driver
    end
    def print(message)
      driver.print(message)  
    end
  end
  
  class Lcd1602Driver  
    require 'wiringpi'
   
    # R/W pin is pulled low (write only)
    # 'enable' pin is toggled to write data to the registers
    
    # Pin layout for LCD, the PI GPIO pins are between brackets, the wiringPI pinnumber is after the slash:
    # 01 Ground
    # 02 VCC - 5v
    # 03 Contrast adjustment (VO) from potentio meter
    # 04 (25/6) Register select (RS), RS=0: Command, RS=1: Data
    # 05 (1/?) Read/Write (R/W) R/W=0: Write, R/W=1: read (This pin is not used/always set to 1)
    # 06 (24/5) Clock (Enable) Falling edge triggered
    # 07 Bit 0 (Not used in 4-bit operation)
    # 08 Bit 1 (Not used in 4-bit operation)
    # 09 Bit 2 (Not used in 4-bit operation)
    # 10 Bit 3 (Not used in 4-bit operation)
    # 11 (23/4) Bit 4
    # 12 (17/0) Bit 5
    # 13 (21/2) Bit 6
    # 14 (22/3) Bit 7
    # 15 Backlight LED Anode (+)
    # 16 Backlight LED Cathode (-)
  
    T_MS = 1.0000000/1000000
    P_RS = 11 # GPIO 7
    P_RW = 99 #Bogus number not used at this moment
    P_EN = 10 # 8
    P_D0 = 99 #Bogus number not used at this moment
    P_D1 = 99 #Bogus number not used at this moment
    P_D2 = 99 #Bogus number not used at this moment
    P_D3 = 99 #Bogus number not used at this moment
    P_D4 = 6 # 25
    P_D5 = 5 # 24
    P_D6 = 4 # 23
    P_D7 = 1 # 18
    ON   = 1
    OFF  = 0
    # 0b00000
    P_RS_BIT_MASK = 1 << 4 
    P_D7_BIT_MASK = 1 << 3
    P_D6_BIT_MASK = 1 << 2 
    P_D5_BIT_MASK = 1 << 1 
    P_D4_BIT_MASK = 1 << 0
  
    @@charCount = 0
    @@onPi      = true # So I can debug the non-RaspberryPi code on a separate machine
    @@initialized = false

    class << self
      def initialized?
        @@initialized
      end
      def init
        if (@@onPi == true)
          Wiringpi.wiringPiSetup
    
          # Set all pins to output mode (not sure if this is needed)
          Wiringpi.pinMode(P_RS, 1)
          Wiringpi.pinMode(P_EN, 1)
          Wiringpi.pinMode(P_D4, 1)
          Wiringpi.pinMode(P_D5, 1)
          Wiringpi.pinMode(P_D6, 1)
          Wiringpi.pinMode(P_D7, 1)
    
          initDisplay()
          sleep T_MS * 10
          lcdDisplay(ON, ON, OFF)
          setEntryMode()
          @@initialized = true
        end
    end
    
      def pulseEnable()
        # Indicate to LCD that command should be 'executed'
        Wiringpi.digitalWrite(P_EN, 0)
        sleep T_MS * 10
        Wiringpi.digitalWrite(P_EN, 1)
        sleep T_MS * 10
        Wiringpi.digitalWrite(P_EN, 0)
        sleep T_MS * 10
      end
    
      def digitalWriteByte(byte)
        Wiringpi.digitalWrite(P_RS, byte & P_RS_BIT_MASK)
        Wiringpi.digitalWrite(P_D7, byte & P_D7_BIT_MASK)
        Wiringpi.digitalWrite(P_D6, byte & P_D6_BIT_MASK)
        Wiringpi.digitalWrite(P_D5, byte & P_D5_BIT_MASK)
        Wiringpi.digitalWrite(P_D4, byte & P_D4_BIT_MASK)
        pulseEnable()                
      end
    
      # Turn on display and cursor
      def lcdDisplay(display, cursor, block)
        digitalWriteByte(0)
        digitalWriteByte("01#{display}#{cursor}#{block}".to_i(2))        
        #display # 1 = 0n
        # cursor # 1 = Cursor on, 0 = Cursor off
        # block  # 1 = Block, 0 = Underline cursor
      end
    
      def setEntryMode()
        # Entry mode set: move cursor to right after each DD/CGRAM write
        Wiringpi.digitalWrite(P_RS, 0)
       
        Wiringpi.digitalWrite(P_D7, 0)
        Wiringpi.digitalWrite(P_D6, 0)
        Wiringpi.digitalWrite(P_D5, 0)
        Wiringpi.digitalWrite(P_D4, 0)
        pulseEnable()
    
        Wiringpi.digitalWrite(P_RS, 0)
       
        Wiringpi.digitalWrite(P_D7, 0)
        Wiringpi.digitalWrite(P_D6, 1)
        Wiringpi.digitalWrite(P_D5, 1)
        Wiringpi.digitalWrite(P_D4, 0)
        pulseEnable()
        sleep T_MS
      end
    
      def lcdWrite(charArray)
        # Write data to CGRAM/DDRAM
        Wiringpi.digitalWrite(P_RS, 1)   
        Wiringpi.digitalWrite(P_D7, charArray[0])
        Wiringpi.digitalWrite(P_D6, charArray[1])
        Wiringpi.digitalWrite(P_D5, charArray[2])
        Wiringpi.digitalWrite(P_D4, charArray[3])
        pulseEnable()
    
        Wiringpi.digitalWrite(P_RS, 1)   
        Wiringpi.digitalWrite(P_D7, charArray[4])
        Wiringpi.digitalWrite(P_D6, charArray[5])
        Wiringpi.digitalWrite(P_D5, charArray[6])
        Wiringpi.digitalWrite(P_D4, charArray[7])
        pulseEnable()
    
        @@charCount += 1
      end
    
      def cls()
        # Clear all data from screen
        Wiringpi.digitalWrite(P_RS, 0)   
        Wiringpi.digitalWrite(P_D7, 0)
        Wiringpi.digitalWrite(P_D6, 0)
        Wiringpi.digitalWrite(P_D5, 0)
        Wiringpi.digitalWrite(P_D4, 0)
        pulseEnable()
    
        Wiringpi.digitalWrite(P_RS, 0)
       
        Wiringpi.digitalWrite(P_D7, 0)
        Wiringpi.digitalWrite(P_D6, 0)
        Wiringpi.digitalWrite(P_D5, 0)
        Wiringpi.digitalWrite(P_D4, 1)
        pulseEnable()
      end
    
      def initDisplay()
        # Set function to 4 bit operation
        i = 0
        while i < 3     # Needs to be executed 3 times
          # Wait > 40 MS
          sleep 42 * T_MS
          Wiringpi.digitalWrite(P_RS, 0)
         
          Wiringpi.digitalWrite(P_D7, 0)
          Wiringpi.digitalWrite(P_D6, 0)
          Wiringpi.digitalWrite(P_D5, 1)
          Wiringpi.digitalWrite(P_D4, 1)
          pulseEnable()
          i += 1
        end
    
        # Function set to 4 bit
        i = 0
        while i < 2  # Needs to be executed 2 times
          Wiringpi.digitalWrite(P_RS, 0)
         
          Wiringpi.digitalWrite(P_D7, 0)
          Wiringpi.digitalWrite(P_D6, 0)
          Wiringpi.digitalWrite(P_D5, 1)
          Wiringpi.digitalWrite(P_D4, 0)
          pulseEnable()
          i += 1
        end
    
        # Set number of display lines
        Wiringpi.digitalWrite(P_RS, 0)
       
        Wiringpi.digitalWrite(P_D7, 1) #  N = 0 = 1 line display
        Wiringpi.digitalWrite(P_D6, 0) #  F = 0 = 5x8 character font
        Wiringpi.digitalWrite(P_D5, 0)
        Wiringpi.digitalWrite(P_D4, 0)
        pulseEnable()
    
        sleep T_MS
    
        # Display Off (2 blocks)
        Wiringpi.digitalWrite(P_RS, 0)
       
        Wiringpi.digitalWrite(P_D7, 0)
        Wiringpi.digitalWrite(P_D6, 0)
        Wiringpi.digitalWrite(P_D5, 0)
        Wiringpi.digitalWrite(P_D4, 0)
        pulseEnable()
    
        sleep T_MS
    
        Wiringpi.digitalWrite(P_RS, 0)
       
        Wiringpi.digitalWrite(P_D7, 1)
        Wiringpi.digitalWrite(P_D6, 0)
        Wiringpi.digitalWrite(P_D5, 0)
        Wiringpi.digitalWrite(P_D4, 0)
        pulseEnable()
    
        sleep T_MS
    
        # Display clear (2 blocks)
        Wiringpi.digitalWrite(P_RS, 0)
       
        Wiringpi.digitalWrite(P_D7, 0)
        Wiringpi.digitalWrite(P_D6, 0)
        Wiringpi.digitalWrite(P_D5, 0)
        Wiringpi.digitalWrite(P_D4, 0)
        pulseEnable()
    
        sleep T_MS
    
        Wiringpi.digitalWrite(P_RS, 0)
       
        Wiringpi.digitalWrite(P_D7, 0)
        Wiringpi.digitalWrite(P_D6, 0)
        Wiringpi.digitalWrite(P_D5, 0)
        Wiringpi.digitalWrite(P_D4, 1)
        pulseEnable()
    
        sleep T_MS
    
        # Entry mode set"
        Wiringpi.digitalWrite(P_RS, 0)
       
        Wiringpi.digitalWrite(P_D7, 0)
        Wiringpi.digitalWrite(P_D6, 0)
        Wiringpi.digitalWrite(P_D5, 0)
        Wiringpi.digitalWrite(P_D4, 0)
        pulseEnable()
    
        sleep T_MS
    
        Wiringpi.digitalWrite(P_RS, 0)   
        Wiringpi.digitalWrite(P_D7, 0)
        Wiringpi.digitalWrite(P_D6, 1)
        Wiringpi.digitalWrite(P_D5, 1) # 1 = Increment by 1
        Wiringpi.digitalWrite(P_D4, 1) # 0 = no shift
        pulseEnable()
      end
    
      def doLcdPrint(theText)
        # Loop through each character in the string, convert it to binary, and print it to the LCD
         theText.size.times.each  do | i |
          theChar = theText[i] 
          #puts theChar
          #binChar = @parseBin.getBin(theChar)
          binChar = theChar.bytes.first.to_s(2)
          while binChar.length < 8
            binChar = "0" + binChar
          end
    
          binCharArray = []
          
          binChar.split(//).each{ |intChar| binCharArray << intChar.to_i  }
    
          if (binChar)
            if (@@onPi == true)
              lcdWrite(binCharArray)
            end
            binChar = nil
          end
        end
      end
    
      def nextLine()
        # Display automatically goes to next line when we hit 40 chars
        fillStr  = " "
        fillCntr = 1
    
        while (@@charCount + fillCntr < 40)
          fillStr += " "
          fillCntr += 1
        end
    
        Lcd1602Driver.doLcdPrint(fillStr)
    
        @@charCount = 0
      end
    
      def print(theText)
      # If the string is longer than 16 char - split it.
      if (theText.length > 16)
        theText.split(" ").each { | theTextCut |
          doLcdPrint(theTextCut)
          nextLine()
          sleep 1
        }
      else
        doLcdPrint(theText)
      end
      nextLine()
    end
  
      def test 
        lcdPrint("Hello Dave.")
        sleep T_MS
        nextLine()
        sleep T_MS
        lcdPrint("How are things?")
        sleep 3
        nextLine()
        sleep T_MS
        cls()
        lcdPrint("Opening the ")
        sleep T_MS
        nextLine()
        lcdPrint("bay doors now...")
        #lcdWrite()
        sleep 10
        cls()
      end
  
    end
  end
end