User Manual
Cursor Left
ASCII 'L', Hex 4C, Decimal 76
Syntax 0xFE 0x4C
To move the cursor one space to the left of current position, send a command prefix followed by the character 'L'.
Cursor Right
ASCII 'M', Hex 4D, Decimal 77
Syntax 0xFE x04D
To move the cursor one space to the right of the current position, send a command prefix followed by the character 'M'.
Cursor Blink On
ASCII 'S', Hex 53, Decimal 83
Syntax 0xFE 0x53
To turn on the blinking cursor at the current position, send a command prefix followed by the character 'S'. Please note that
the blinking cursor is on by default at power up.
Cursor Blink Off
ASCII 'T', Hex 54, Decimal 84
Syntax 0xFE 0x54
To turn off the blinking cursor at the current position send a command prefix followed by the character 'T'.
Set Debounce Time
ASCII 'U', Hex 55, Decimal 85
Syntax 0xFE 0x55<number to define debounce time>
To set the time between key press and key read, send a command prefix followed by the character 'U' and a number to
define the debounce time. All key types with the exception of latched piezo switches will"bounce" for a varying time,
depending on their physical characteristics. The default debounce time for the module is about 65mS, which is adequate
for most membrane keypads. This time equates to a setting of 8 using this command as there is a debounce time resolution
of 8192 microseconds.
Create Custom Character
ASCII 'N', Hex 4E, Decimal 78
Syntax 0xFE 0x4E<character between 0x00 and 0x07><8 bytes>
This command creates a custom character. For the VFD2021 the user can have up to eight custom characters. To execute
this command, send a command prefix followed by the character 'N'. The display will now await the number which identi-
fies the custom character. This number must be between 0x00 and 0x07. When the module determines what character it's
working on, then the user must send 8 bytes which define the display character. See the diagram below for and explanation
of the display character structure.
Diagram A
7
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