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Override the LCD-PIN select options.










The name of the PORT pin such as PORTB.2 for example.


When you want to use the LCD in 8 bit data, pin mode, you must specify the PORT to use.


A port pin that is connected to the busy pin. The busy pin is only supported by the 20x4VFD display.


A mode for the 20x4VFD display. Options :

0 : 4 bit parallel upper nibble first

1 : 4 bit parallel lower nibble first


You can override the PIN selection from the Compiler Settings with this statement, so a second configuration lets you not choose more pins for a second LCD display.


The config command is preferred over the option settings since the code makes clear which pins are used. The CONFIG statement overrides the Options setting.


The PIN and MODE are only for the 20x4VFD display. See also LCDAUTODIM


The WR pin is optional. When you select the WR pin, an alternative library will be used. This library uses the WR pin and reads the BUSY signal from the LCD.

The library lcd4busy_anypin will be used, which is based on Luciano's LUC_lcd4busy library.

Notice that since 2040 version, the compiler will generate LCD port pin info which you can use for your own libs.


By default the WR pin is optional and the WR signal of the LCD should be connected to ground. This saves the pin for other purposes. When you have enough pins, you better use the WR-pin.

If you do not connect the WR pin to ground but to a pin, and you do not specify the WR pin, but you set the logic level to 0 in your code, you have to use an INITLCD command after you have set the WR pin to 0.



See also






'name                     : lcd.bas

'copyright                : (c) 1995-2021, MCS Electronics

'purpose                  : demo: LCD, CLS, LOWERLINE, SHIFTLCD, SHIFTCURSOR, HOME

'                           CURSOR, DISPLAY

'micro                    : Mega8515

'suited for demo          : yes

'commercial addon needed  : no



$regfile = "m8515.dat"                                     ' specify the used micro

$crystal = 4000000                                         ' used crystal frequency

$baud = 19200                                               ' use baud rate

$hwstack = 32                                               ' default use 32 for the hardware stack

$swstack = 10                                               ' default use 10 for the SW stack

$framesize = 40                                             ' default use 40 for the frame space




'REMOVE the above command for the real program !!

'$sim is used for faster simulation



'note : tested in PIN mode with 4-bit


'Config Lcdpin = Pin , Db4 = Portb.1 , Db5 = Portb.2 , Db6 = Portb.3 , Db7 = Portb.4 , E = Portb.5 , Rs = Portb.6

Config Lcdpin = Pin , Db4 = Porta.4 , Db5 = Porta.5 , Db6 = Porta.6 , Db7 = Porta.7 , E = Portc.7 , Rs = Portc.6

'These settings are for the STK200 in PIN mode

'Connect only DB4 to DB7 of the LCD to the LCD connector of the STK D4-D7

'Connect the E-line of the LCD to A15 (PORTC.7) and NOT to the E line of the LCD connector

'Connect the RS, V0, GND and =5V of the LCD to the STK LCD connector


Rem with the config lcdpin statement you can override the compiler settings



Dim A As Byte

Config Lcd = 16x2                                         'configure lcd screen



'other options are 16 * 4 and 20 * 4, 20 * 2 , 16 * 1a

'When you dont include this option 16 * 2 is assumed

'16 * 1a is intended for 16 character displays with split addresses over 2 lines


'$LCD = address will turn LCD into 8-bit databus mode

'       use this with uP with external RAM and/or ROM

'       because it aint need the port pins !


Cls                                                       'clear the LCD display

Lcd "Hello world."                                         'display this at the top line

Wait 1

Lowerline                                                 'select the lower line

Wait 1

Lcd "Shift this."                                         'display this at the lower line

Wait 1

For A = 1 To 10

Shiftlcd Right                                         'shift the text to the right

Wait 1                                                   'wait a moment



For A = 1 To 10

Shiftlcd Left                                           'shift the text to the left

Wait 1                                                   'wait a moment



Locate 2 , 1                                               'set cursor position

Lcd "*"                                                   'display this

Wait 1                                                     'wait a moment


Shiftcursor Right                                         'shift the cursor

Lcd "@"                                                   'display this

Wait 1                                                     'wait a moment


Home Upper                                                 'select line 1 and return home

Lcd "Replaced."                                           'replace the text

Wait 1                                                     'wait a moment


Cursor Off Noblink                                         'hide cursor

Wait 1                                                     'wait a moment

Cursor On Blink                                           'show cursor

Wait 1                                                     'wait a moment

Display Off                                               'turn display off

Wait 1                                                     'wait a moment

Display On                                                 'turn display on

'-----------------NEW support for 4-line LCD------


Lcd "Line 3"


Lcd "Line 4"

Home Third                                                 'goto home on line three

Home Fourth

Home F                                                     'first letteer also works

Locate 4 , 1 : Lcd "Line 4"

Wait 1


'Now lets build a special character

'the first number is the characternumber (0-7)

'The other numbers are the rowvalues

'Use the LCD tool to insert this line


Deflcdchar 1 , 225 , 227 , 226 , 226 , 226 , 242 , 234 , 228       ' replace ? with number (0-7)

Deflcdchar 0 , 240 , 224 , 224 , 255 , 254 , 252 , 248 , 240       ' replace ? with number (0-7)

Cls                                                       'select data RAM

Rem it is important that a CLS is following the deflcdchar statements because it will set the controller back in datamode

Lcd Chr(0) ; Chr(1)                                       'print the special character


'----------------- Now use an internal routine ------------

_temp1 = 1                                                 'value into ACC

!rCall _write_lcd                                           'put it on LCD