at85c51snd3 ATMEL Corporation, at85c51snd3 Datasheet - Page 234

• Manufacturer Part Number: at85c51snd3
• Description: At85c51snd3 Single-chip Digital Audio Decoder - Encoder With Usb 2.0 Interface
• Manufacturer: ATMEL Corporation

Display Interface
Configuration
Interface Enable
Interface Selection
234
AT85C51SND3B
The AT85C51SND3B derivatives implement a display interface allowing glueless direct
interfacing (thanks to its highly configurable capability) to almost all of the LCD control-
lers found in either graphic or text LCD display.
These LCD controllers interface is from either 6800 or 8080 compatible type with some
variant in the implementation.
The display interfaces to the C51 core through the following special function registers:
LCDCON0, LCDCON1, the LCD control registers (see Table 256 and Table 257); LCD-
STA, the LCD status register (see Table 258); LCDBUM, the LCD busy mask register
(see Table 259); and LCDDAT, the LCD data register (see Table 260).
As shown in Figure 126, the Display Interface is divided in two major blocks: the Access
Cycle Generator which generates read or write cycles to the LCD controller, and the
Busy Check Processor which enables automatic busy checking after any read or write
cycles.
Figure 126. Display Interface Block Diagram
Setting LCEN bit in LCDCON1 enables the display interface. When this bit is cleared, all
signals to the controller are switch back to I/O port alternate function. Thus after reset,
all signals are set to high level.
The display interface is programmed in 6800 type or 8080 type by setting or clearing the
LCIFS bit LCDCON0. Table 255 shows the pin configuration depending on the interface
selected.
Table 255. Pin Configuration vs. LCD Controller Interface Type (6800/8080)
LCDCON1.5
CLOCK
RSCMD
LCDBUM
BU7:0
OSC
Busy Check
Processor
Pin Name
LWR/LRW
LRD/LDE
LA0/LRS
LD7:0
LCS
LCDCON1.2
LCDCON0.7
BUINV
LCEN
LCBUSY
LCDCSTA
LCDCON0.6
LCDCON1.3
LCYCT
LCIFS
8080 Type Controller
LCDCON1.4
LCDCON1.1
LCYCW
LCRD
D7:0
WR
RD
CS
A0
Access Cycle
LCDCON0.5:4
ADSUH1:0
LCDCON1.0
Generator
LCRS
LCDCON1.7:6
LCDCON0.3:0
ACCW3:0
SLW1:0
6800 Type Controller
D7:0
RW
RS
CS
E
7632D–MP3–01/07
LWR/LRW
LRD/LDE
LA0/LRS
LCS
LD7:0