Matrix Orbital VFD2041 Legacy - Manual (Page 18)

VFD2041 rev 2 18
4.1.7 Place large digit 254 35 [col] [digit]
This command allows the large digits to be drawn on the LCD screen. Numbers of almost full display height
may be placed along side regular text on four row displays. The column number has a maximum value
which is less than the display width because the digits are all three columns wide.
Before using this command the Initialize Large Digits command must be issued to define the blocks
necessary to make up the digits. If regular text and large digits are mixed on one screen, the user should
always set the display cursor position before placing regular text because the creation of a large digit will
leave the cursor position to the bottom right of the large digit and not at the last regular text write position.
[col] can have values from 0x01 to 0x12 (1 to 18). [digit] has values from 0x00 to 0x09 (0 to 9).
4.1.8 Define custom character (254 78 [c] [8 bytes])
The VFD2041 allows up to 8 user defined (custom) characters. These characters occupy the first 8 (0x00 to
0x07) places in the character set (see Figure 3-1).
Custom characters occupy a 5 x 8 pixel matrix. Built-in characters are 5 x 7: the bottom row of pixels is
normally reserved for the underline cursor. The underline cursor should be turned off if the bottom row of
pixels forms part of a custom character.
The characters are defined by issuing the command 254 78 [c] followed by 8 bytes to define the character.
[c] is the character number (0x00 to 0x07). The 8 bytes are mapped as shown below:
MSB LSB
* * * 1 2 3 4 5 Data Byte 1
* * * 6 7 8 9 10 Data Byte 2
* * * 11 12 13 14 15 Data Byte 3
* * * 16 17 18 19 20 Data Byte 4
* * * 21 22 23 24 25 Data Byte 5
* * * 26 27 28 29 30 Data Byte 6
* * * 31 32 33 34 35 Data Byte 7
* * * 36 37 38 39 40 Data Byte 8
A "1" bit indicates an on (black) pixel, a "0" bit indicates an off (clear) pixel.
Once defined, a character is displayed simply by issuing a value (0x00 to 0x07) corresponding to the
character number. The character will be laid out as follows: