20T202DA1E Datasheet, PDF (12/17 Pages) Samsung semiconductor – VACUUM FLUORESCENT DISPLAY MODULE

2X20 LCD Compatible VFD Module
20T202DA1E (Rev. 3.0)
6. INSTRUCTIONS
6.1 Outline
Only the instruction register (IR) and the data register (DR) of the VFD controller can be controlled by the user's MPU.
Before starting the internal operation of the controller, control information is temporarily stored into these registers to
allow different data transfer mode, display line setting and dimming control etc. The internal operation of the controller
is determined by signals sent from the MPU. These signals, which include register selection signal (RS), write enable
signal (E), and the data bus (DB4 to DB7), make up the controller instructions.
There are four categories of instructions which are:
* Designate controller functions, such as display format, data length, etc.
* Set internal RAM addresses.
* Perform data transfer with internal RAM.
* Perform miscellaneous functions.
Normally, instructions that perform data transfer with internal RAM are used the most.
However, auto-incrementation by 1 (or auto-decrementation by 1) of internal RAM addresses after each data write can
lighten the program load of the MPU. Since the display shift instruction can perform concurrently with display data
write, the user can minimize system development time with maximum programming efficiency.
*Instruction List
Instructions
RS
Instruction Code
D7 D6 D5 D4 D3 D2 D1 D0
Descriptions
Display Clear
0
0
0
0
0
0
0
0
1
Clears all display and sets DD-RAM address 00
in address counter.
Cursor Home
Sets DD-RAM address 0 in ACC. Also returns
0 0 0 0 0 0 0 1 * the display being shifted to the original position.
DD-RAM contents remain unchanged.
Entry Mode Set
Sets the cursor direction and specifies display
0 0 0 0 0 0 1 I/D S shift. These operations are performed during
writing/reading data.
Display ON/OFF Control 0
0
0
0
0
1
DC
B
Sets all display ON/OFF (D), cursor ON/OFF (C),
cursor blink of character position (B).
Cursor or Display Shift
0
0
0
0
1 S/C R/L *
*
Shifts display or cursor, keeping DD-RAM
contents.
Function Set
0
0
0
1
IF N
*
BR1
BR0
Sets data length (IF), number of display lines (N),
Set brightness level (BR1,BR0)
CG-RAM Address Set
00 1
ACG (CG-RAM Address) Sets the CG-RAM address.
DD-RAM Address Set 1 1
ADD (DD-RAM Address)
Sets the DD-RAM address.
Data Writing to CG- or
DD-RAM
1
Character Code
Writes data into CG-RAM or DD-RAM.
REMARKS:
* I/D = 1: Increment
* I/D = 0: Decrement
* DD-RAM: Display
Data RAM
* S = 1: Display Shift Enabled
* CG-RAM: Character * S = 0: Cursor Shift Enabled
Generator RAM
* ACG: CG-RAM
* S/C = 1: Display Shift
Address
* S/C = 0: Cursor Move
* ADD: DD-RAM
Address
* R/L = 1: Shift to the Right
* ACC: Address Counter * R/L = 0: Shift to the Left
* IF = 1: 8-bit Operation
* IF = 0: 4-bit Operation
* N = 1: 2 Lines Display
* N = 0: 1 Line Display
* BR1, BR0 =
00: 100%, 01: 75%, 10: 50%, 11: 25%
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