Chapter 5: Character Lcd Screen; Overview - Xilinx Spartan-3A User Manual

R
Character LCD Screen

Overview

The Spartan-3A/3AN Starter Kit board prominently features a 2-line by 16-character
liquid crystal display (LCD). The FPGA controls the LCD via the eight-bit data interface
shown in
interface to remain compatible with other Xilinx development boards.
Once mastered, the LCD is a practical way to display a variety of information using
standard ASCII and custom characters. However, these displays are not fast. Scrolling the
display at half-second intervals tests the practical limit for clarity. Compared with the
50 MHz clock available on the board, the display is slow. A PicoBlaze processor efficiently
controls display timing plus the actual content of the display.
Spartan-3A/3AN Starter Kit Board User Guide
UG334 (v1.0) May 28, 2007
Figure 5-1. The Spartan-3A/3AN Starter Kit board also supports the four-bit data
Caution!
When using four-bit mode, the FPGA must drive the LCD_DB<3:0> signals High.
FPGA
(Y15)
(AB16)
(Y16)
(AA12)
(AB12)
(AB17)
(AA13)
(Y13)
(AB4)
(Y14)
(W13)
Figure 5-1: Character LCD Interface
www.xilinx.com
Character LCD
All
390Ω
LCD_DB<7>
DB7
LCD_DB<6>
DB6
LCD_DB<5>
DB5
LCD_DB<4>
DB4
LCD_DB<3>
DB3
LCD_DB<2>
DB2
LCD_DB<1>
DB1
LCD_DB<0>
DB0
LCD_E
E
LCD_RS
RS
LCD_RW
R/W
Chapter 5
Display
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