Matrix Orbital VFD2041 Legacy - Manual (Page 23)

VFD2041 rev 2 23
0111 7 7 1111 F 15
Based on the table, the byte 01001011 can be represented in hex as 4B, which is usually written as any of
4Bh, 4BH, 4B hex or 0x4B.
The numbers can also be expressed in decimal form if preferred.
6.3.1 ASCII Characters
Since computers deal internally with numbers only, but externally with both letters and numbers, several
schemes were developed to "map" written characters to numeric values. One such scheme has become
universal, the American Standard Code for Information Interchange, or ASCII. ASCII tables are readily
available from a number of sources. A few examples will do here:
The letter A has a value of 65 decimal or 41 hex
The letter a has a value of 97 decimal or 61 hex
The number 0 has a value of 48 decimal or 30 hex
The number 9 has a value of 57 decimal or 39 hex
This gives rise to the possibility of confusion when parameters are being set on the VFD2041 For example,
the GPO ON and OFF commands use a number to indicate which GPO is being controlled.
We're told that
acceptable values are 0 to 6. All such parameters must use numeric values (i.e. the actual byte values).
If we send the ASCII number 0 by mistake it will actually give the value 48 decimal (30 hex) to the
parameter, which is wrong. In the tables given in the following sections ASCII characters are shown as 'A',
with single quotes.
6.4 Text Commands
See Chapter 3 for command descriptions. Syntax in the tables below is given in hex, decimal and decimal
with ASCII, in that order, one per line.
Table 6-1 Text Commands
Command Syntax Default Notes
Auto line wrap on FE 43
254 67
254 'C' off
Enables line wrapping (not word wrap).
Auto line wrap off FE 44
254 68
254 'D' off
Disables line wrapping.
Auto scroll on FE 51
254 81
254 'Q' off
Enables scroll at bottom of screen. Text will
push display up one line to make room for new
line.
Auto scroll off FE 52
254 82
254 ‘R’ off
Disables auto scroll. Text will wrap to top left
and overwrite existing text.
Set cursor position FE 47 [col] [row]
254 71 [col] [row]
254 'G' [col] [row] n/a Moves cursor to the specified column and row.
The cursor marks the text insertion point in
this and all commands.
Send cursor home FE 48
254 72 This command moves the cursor to the top left
of the display area.