Matrix Orbital LCD0821 Legacy - Manual (Page 15)

LCD0821 rev 2 15
In addition to the built-in characters, users may define up to 8 special characters (which, once defined,
occupy positions 0x00 to 0x07 in the above chart). The LCD0821 does not have provision to download
other fonts.
3.3 Writing Text to the Display
When the display receives a character, it displays that character at the position currently defined. The next
character sent to the module then advances to the following position on the display. Characters are drawn
using the built-in font, and only characters defined in the font are actually displayed. Characters that are not
defined by the built-in font print as a space (i.e. the cursor is advanced for the next character).
The position where text is to be inserted is a character location stored in the LCD0821's volatile memory
and maintained internally by the LCD0821's firmware. This position is manipulated by the commands
shown in the following section.
3.4 Text Commands
In this section commands are identified by their names and decimal values. Hex and ASCII equivalents are
given in the summary (Table 6-1). Before issuing commands to the LCD0821 please read sections 6.2
and 6.3.
3.4.1 Auto line wrap on (254 67)
Enables automatic line wrapping. Note that this is not "word wrapping" and wraps may occur in the middle
of a word. Note that if auto line wrap and auto scroll are both off (default) text will wrap from line 1 to line
3 then 2 then 4. Default is OFF.
3.4.2 Auto line wrap off (254 68)
Disables automatic line wrapping.
3.4.3 Auto scroll on (254 81)
When auto scrolling is on, it causes the LCD0821 to shift the entire display’s contents up to make room for
a new line of text when the text reaches the scroll position (the bottom right character position). Default is
OFF.
3.4.4 Auto scroll off (254 82)
When auto scrolling is disabled, text will wrap to the top left corner of the display area instead of scrolling.
Existing text in the display area is not erased before new text is placed. A series of "spaces" followed by a
Cursor Home command may be used to erase the top line of text.
3.4.5 Set cursor position (254 71 [column] [row])
This command sets the cursor position (text insertion point) to the [column] and [row] specified. Columns
have values from 1 to 20 (0x01 to 0x14) and rows have values of 1 to 4 (0x01 to 0x04).
3.4.6 Send cursor home (254 72)
This command moves the cursor position (text insertion point) to the top left of the display area.