' Some preamble
dim integer d4 = 5, d5 = 4, d6 = 3, d7 = 2, rs = 6, en = 7, en_sel = 9, en1 = 0, en2 = 1 'LCD variables
'LCD Setup 40x4 display treated as 2 x 20x2 displays. Subroutines used to emulate normal LCD Cmds.
'set cursor value below as:   12 = 0ff
'                             13 = blinking ON OFF #
'                             14 = solid "_"
'                             15 = blinking solid "_#"
cursor = 12         'set cursor OFF
lcd_init d4,d5,d6,d7,rs,en    'Pins 5,4,3,2,6,7  initialise the LCD
'* NOTE LCD INIT in LCD_CLOSE routine

%%%%%%%%%%%  LCD ROUTINES  %%%%%%%%%%%%%%%%%%
'  'The 40 chr x 4 line LCD has to be treated as 2 separate LCD's or sections.
'  'MMBasic requires a LCD Close before an initialzation.
'  'The first section is selected & then initalised "LCD INIT".
'  'The second selection is then selected then the CLOSE command sent which
'  'satisfies MMBasic.
'  'The LCD INIT is then sent to the second section
'
sub LCD_INIT (d4,d5,d6,d7,rs,en)  '4 data bits plus select & enable
pin(en_sel) = en1                 'first section - top 2 lines or rows
LCD init d4,d5,d6,d7,rs,en        'Initialise section section
lcd_cmd 1, cursor                 'set cursor mode top section
pin(en_sel) = en2                 'second section -3rd & 4th lines
lcd close                         'Terminate function in MMBasic
lcd init d4,d5,d6,d7,rs,en        'Initialise section section
lcd_cmd 3, cursor                 'set cursor mode bottom section
end SUB

' Each section cleared in turn
sub LCD_Clear()
pin(en_sel) = en1                 'Select first section
LCD CLEAR                         'clear it
pin(en_sel) = en2                 'Select second section
lcd clear                         'Clear it
lcd_cmd 1, 2                      'row 1, cursor to start
end SUB

'Close Display. Each section closed in turn
sub LCD_Close()
pin(en_sel) = en1                 'select first selection
LCD CLose                         'close top section
pin(en_sel) = en2                 'select second selection
lcd init d4,d5,d6,d7,rs,en        'Have to re-initialise before another close.
lcd close                         'close bottom section
'setpin en_sel, off               'release the select pin
End SUB

'writes data (words$) to selected line & position & sets cursor position if enabled
sub LCD_Write (row, position, words$)
if row > 4 then row = 4
if row =< 2  then               'check if row 1 or 2
lcd_cmd 3, cursor_off         'go turn cursor off bottom section
lcd_cmd 1, cursor             'set cursor mode top section
pin(en_sel) = en1             'yes. Enable this section
lcd row, position, words$     'write data to appropriate pos & row
else if row => 3 then
pin(en_sel) = en1
lcd_cmd 1, cursor_off         'turns cursor off bottom section
lcd_cmd 3, cursor             'set cursor mode
pin(en_sel) = en2             'select bottom section
row = row - 2                 'select appropriate row in bottom section. (1 or 2)
lcd row, position, words$
end if
end sub

sub LCD_CMD (row, action)
if row = 2 and action >= 128 then action = action + 40
if row = 4 and action >= 128 then action = action + 40
if row <= 2  then
pin(en_sel) = en1
lcd cmd action
pin(en_sel) = en2
else if row => 3 then
pin(en_sel) = en2
lcd cmd action
pin(en_sel) = en1
end if
end sub

sub LCD_DATA (row, action1)
if row <= 2  then
pin(en_sel) = en1
lcd cmd Cursor
lcd data action1
pin(en_sel) = en2
lcd cmd cursor
else if row => 3 then
pin(en_sel) = en2
lcd cmd cursor
lcd data action1
pin(en_sel) = en1
lcd cmd cursor
end if
end sub