Lcd Controller; Memory Map; Dd Ram - Xilinx Spartan-3A User Manual

R

LCD Controller

The 2 x 16 character LCD has an internal Sitronix
functionally equivalent with the following devices.
•
•
•

Memory Map

The controller has three internal memory regions, each with a specific purpose: DD RAM,
CG ROM, and CG RAM. The display must be initialized before accessing any of these
memory regions.

DD RAM

The Display Data RAM (DD RAM) stores the character code to be displayed on the screen.
Most applications interact primarily with DD RAM. The character code stored in a DD
RAM location references a specific character bitmap stored either in the predefined
ROM
Figure 5-3
upper line of characters is stored between addresses 0x00 and 0x0F. The second line of
characters is stored between addresses 0x40 and 0x4F.
00 01 02 03
1
2 40 41 42 43
1 2 3 4
Figure 5-3: DD RAM Hexadecimal Addresses (No Display Shifting)
Physically, there are 80 total character locations in DD RAM with 40 characters available
per line. Locations 0x10 through 0x27 and 0x50 through 0x67 can be used to store other
non-display data. Alternatively, these locations can also store characters that can only be
displayed using controller's display shifting functions.
Spartan-3A/3AN Starter Kit Board User Guide
UG334 (v1.0) May 28, 2007
NET "LCD_E" LOC = "AB4" |
NET "LCD_RS" LOC = "Y14" |
NET "LCD_RW" LOC = "W13" |
NET "LCD_DB<7>" LOC = "Y15"
NET "LCD_DB<6>" LOC = "AB16" |
NET "LCD_DB<5>" LOC = "Y16"
NET "LCD_DB<4>" LOC = "AA12" |
NET "LCD_DB<3>" LOC = "AB12" |
NET "LCD_DB<2>" LOC = "AB17" |
NET "LCD_DB<1>" LOC = "AB18" |
NET "LCD_DB<0>" LOC = "Y13"
Figure 5-2: UCF Location Constraints for the Character LCD
Samsung S6A0069X or KS0066U
Hitachi HD44780
SMOS SED1278
character set or in the user-defined
shows the default address for the 32 character locations on the display. The
Character Display Addresses
04 05 06 07 08
44 45 46 47 48
5 6 7 8 9
www.xilinx.com
IOSTANDARD = LVCMOS33 |
IOSTANDARD = LVCMOS33 |
IOSTANDARD = LVCMOS33 |
| IOSTANDARD = LVCMOS33 |
IOSTANDARD = LVCMOS33 |
| IOSTANDARD = LVCMOS33 |
IOSTANDARD = LVCMOS33 |
IOSTANDARD = LVCMOS33 |
IOSTANDARD = LVCMOS33 |
IOSTANDARD = LVCMOS33 |
| IOSTANDARD = LVCMOS33 |
ST7066U
CG RAM character set.
09 0A 0B 0C 0D
49 4A 4B 4C 4D
10 11 12 13 14
LCD Controller
DRIVE = 4 | SLEW = QUIETIO ;
DRIVE = 4 | SLEW = QUIETIO ;
DRIVE = 4 | SLEW = QUIETIO ;
DRIVE = 4 | SLEW = QUIETIO ;
DRIVE = 4 | SLEW = QUIETIO ;
DRIVE = 4 | SLEW = QUIETIO ;
DRIVE = 4 | SLEW = QUIETIO ;
DRIVE = 4 | SLEW = QUIETIO ;
DRIVE = 4 | SLEW = QUIETIO ;
DRIVE = 4 | SLEW = QUIETIO ;
DRIVE = 4 | SLEW = QUIETIO ;
graphics controller that is
CG
Undisplayed
Addresses
0E 0F 10 ...
4E 4F 50 ...
15 16 17 ...
27
67
40
45