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Add HD44780 example
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‎ioio/samples/hd44780.bas

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' HD44780 - Text LCD
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' ==================
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'
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' This example demonstrates how to use the alphanumeric
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' dot matrix liquid crystal display HD44780.
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'
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' Connect the LCD to the IOIO-OTG board:
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'
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' ------- ------ 1 (GND)
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' IOIO | |HD44780 |
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' PIN 41|-------|11 (DB4) ---
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' PIN 42|-------|12 (DB5) | |
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' PIN 43|-------|13 (DB6) |10K|<---3 (VEE)
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' PIN 44|-------|14 (DB7) | |
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' GND |-------| 5 (RW) ---
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' PIN 45|-------| 6 (E) |
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' PIN 46|-------| 4 (RS) 2 (VIN)
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' GND |-------| 1 (GND)
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' 5V |-------| 2 (VIN)
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'-------- --------
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' A potentiometer needs to be connected to the display
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' to control the contrast of the display. If the display
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' has a background light, connect power according to the
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' data sheet to the pins 15 and 16.
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'
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' Code based on https://www.mikrocontroller.net/articles/AVR-GCC-Tutorial/LCD-Ansteuerung
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'#########################################################
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'# Constant definition #
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'#########################################################
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const LCD_CLEAR_DISPLAY = 0x01
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const LCD_CURSOR_HOME = 0x02
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const LCD_SET_ENTRY = 0x04
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const LCD_ENTRY_DECREASE = 0x00
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const LCD_ENTRY_INCREASE = 0x02
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const LCD_ENTRY_NOSHIFT = 0x00
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const LCD_ENTRY_SHIFT = 0x01
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const LCD_SET_DISPLAY = 0x08
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const LCD_DISPLAY_OFF = 0x00
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const LCD_DISPLAY_ON = 0x04
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const LCD_CURSOR_OFF = 0x00
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const LCD_CURSOR_ON = 0x02
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const LCD_BLINKING_OFF = 0x00
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const LCD_BLINKING_ON = 0x01
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const LCD_SET_SHIFT = 0x10
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const LCD_CURSOR_MOVE = 0x00
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const LCD_DISPLAY_SHIFT = 0x08
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const LCD_SHIFT_LEFT = 0x00
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const LCD_SHIFT_RIGHT = 0x04
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const LCD_SET_FUNCTION = 0x20
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const LCD_FUNCTION_4BIT = 0x00
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const LCD_FUNCTION_8BIT = 0x10
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const LCD_FUNCTION_1LINE = 0x00
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const LCD_FUNCTION_2LINE = 0x08
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const LCD_FUNCTION_5X7 = 0x00
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const LCD_FUNCTION_5X10 = 0x04
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const LCD_SOFT_RESET = 0x30
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const LCD_SET_CGADR = 0x40
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const LCD_DDADR_LINE1 = 0x00
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const LCD_DDADR_LINE2 = 0x40
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const LCD_DDADR_LINE3 = 0x10
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const LCD_DDADR_LINE4 = 0x50
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const LCD_GC_CHAR0 = 0
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const LCD_GC_CHAR1 = 1
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const LCD_GC_CHAR2 = 2
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const LCD_GC_CHAR3 = 3
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const LCD_GC_CHAR4 = 4
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const LCD_GC_CHAR5 = 5
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const LCD_GC_CHAR6 = 6
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const LCD_GC_CHAR7 = 7
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const LCD_SET_DDADR = 0x80
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'#########################################################
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'# Main program #
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'#########################################################
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import ioio
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Print "Connect to HD44780"
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RS = ioio.openDigitalOutput(46)
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E = ioio.openDigitalOutput(45)
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DB4 = ioio.openDigitalOutput(41)
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DB5 = ioio.openDigitalOutput(42)
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DB6 = ioio.openDigitalOutput(43)
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DB7 = ioio.openDigitalOutput(44)
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ioio.waitForConnect(10)
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Print "Connection established"
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Init()
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LCD_Write(" Hello World")
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LCD_Locate(1,2)
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LCD_Write("-= SmallBASIC =-")
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print "Done"
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end
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'#########################################################
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'# Functions and subs #
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'#########################################################
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sub Init()
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RS.write(0)
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E.write(0)
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DB4.write(0)
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DB5.write(0)
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DB6.write(0)
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DB7.write(0)
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delay(50)
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' Send soft-reset 3 time to initialize LCD
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Send4Bit(LCD_SOFT_RESET)
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delay(5)
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SendEnable()
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delay(1)
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SendEnable()
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delay(1)
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' Set 4-bit mode
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Send4Bit(LCD_SET_FUNCTION BOR LCD_FUNCTION_4BIT)
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delay(5)
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' 2 lines and 5x7 pixel in 4 bit mode
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SendCommand(LCD_SET_FUNCTION BOR LCD_FUNCTION_4BIT BOR LCD_FUNCTION_2LINE BOR LCD_FUNCTION_5X7)
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' Display on, cursor off and blinking off
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SendCommand(LCD_SET_DISPLAY BOR LCD_DISPLAY_ON BOR LCD_CURSOR_OFF BOR LCD_BLINKING_OFF)
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' Cursor increment no scrolling
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SendCommand(LCD_SET_ENTRY BOR LCD_ENTRY_INCREASE BOR LCD_ENTRY_NOSHIFT )
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LCD_Cls()
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end
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sub LCD_Write(Text)
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' Write characters to lcd
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local length, t
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length = len(Text)
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for i = 1 to length
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t = asc(mid(text, i, 1))
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SendData(t)
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next
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end
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sub LCD_Cls()
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SendCommand(LCD_CLEAR_DISPLAY)
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SendCommand(LCD_CURSOR_HOME)
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end
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sub LCD_Off()
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SendCommand(LCD_SET_DISPLAY BOR LCD_DISPLAY_OFF)
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end
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sub LCD_On()
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SendCommand(LCD_SET_DISPLAY BOR LCD_DISPLAY_ON)
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end
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sub LCD_Locate(x, y)
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local dat
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if(x < 1) then x == 1
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select case y
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case 1 ' 1. line
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dat = LCD_SET_DDADR + LCD_DDADR_LINE1 + x - 1
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case 2 ' 2. line
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dat = LCD_SET_DDADR + LCD_DDADR_LINE2 + x - 1
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case 3 ' 3. line
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dat = LCD_SET_DDADR + LCD_DDADR_LINE3 + x - 1
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case 4 ' 4. line
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dat = LCD_SET_DDADR + LCD_DDADR_LINE4 + x - 1
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case else
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return
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end select
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SendCommand(dat)
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end
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sub SendCommand(cmd)
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RS.write(0)
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SendByte(cmd)
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end
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sub SendData(dat)
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RS.write(1)
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SendByte(dat)
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end
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sub SendEnable()
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E.write(1)
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delay(1)
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E.write(0)
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delay(1)
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end
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sub SendByte(byte)
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Send4Bit(byte) ' Send high bits first
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Send4Bit(byte lshift 4) ' Send low bits
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end
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sub Send4Bit(byte)
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DB7.write(GetBit(byte, 7))
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DB6.write(GetBit(byte, 6))
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DB5.write(GetBit(byte, 5))
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DB4.write(GetBit(byte, 4))
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SendEnable()
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end
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func GetBit(value, bit)
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return (value rshift bit) BAND 1
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end

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