
Spartan-3A/3AN FPGA Starter Kit Board User Guide
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49
UG334 (v1.1) June 19, 2008
LCD Controller
R
Disabled
If the LCD_E enable signal is Low, all other inputs to the LCD are ignored.
Clear Display
Clears the display and returns the cursor to the home position, the top-left corner.
This command writes a blank space (ASCII/ANSI character code 0x20) into all DD RAM
addresses. The address counter is reset to 0, location 0x00 in DD RAM. Clears all option
settings. The I/D control bit is set to 1 (increment address counter mode) in the
Entry Mode
Set
command.
Execution Time: 82
µ
s – 1.64 ms
Return Cursor Home
Returns the cursor to the home position, the top-left corner. DD RAM contents are
unaffected. Also returns the display being shifted to the original position, shown in
Figure 5-3
.
The address counter is reset to 0, location 0x00 in DD RAM. The display is returned to its
original status if it was shifted. The cursor or blink move to the top-left character location.
Execution Time: 40
µ
s – 1.6 ms
Entry Mode Set
Sets the cursor move direction and specifies whether or not to shift the display.
These operations are performed during data reads and writes.
Execution Time: 40
µ
s
Bit DB1: (I/D) Increment/Decrement
This bit either auto-increments or auto-decrements the DD RAM and CG RAM address
counter by one location after each
Write Data to CG RAM or DD RAM
command or
Read
Function Set
0
0
0
0
1
0
1
0
-
-
Set CG RAM Address
0
0
0
1
A5
A4
A3
A2
A1
A0
Set DD RAM Address
0
0
1
A6
A5
A4
A3
A2
A1
A0
Read Busy Flag and Address
0
1
BF
A6
A5
A4
A3
A2
A1
A0
Write Data to CG RAM or DD RAM
1
0
D7
D6
D5
D4
D3
D2
D1
D0
Read Data from CG RAM or DD RAM
1
1
D7
D6
D5
D4
D3
D2
D1
D0
Table 5-2:
LCD Character Display Command Set (4-bit mode)
(Continued)
Function
LC
D
_
R
S
LCD_R
W
Upper Nibble
Lower Nibble
DB
7
DB
6
DB
5
DB
4
DB
3
DB
2
DB
1
DB
0
0
Auto-decrement address counter. Cursor/blink moves to left.
1
Auto-increment address counter. Cursor/blink moves to right.