Signals; Lcd Interface Signal List - Intel PXA27 Series Design Manual

LCD Interface
The PXA27x processor supports these types of panels:
•
Single- or dual-scan display modules
•
Up to 256 gray-scale levels (8 bits) in passive monochrome mode
•
Up to 16777216 colors (24 bits) in active color mode
•
A total of 16777216 colors (24 bits) in passive color mode
•
LCD panels with an internal frame buffer (smart panels)
•
Up to 8-bit (each) passive dual-scan color displays
•
Up to 18-bit per pixel for active single-panel color displays
•
Up to 24-bit per pixel single-panel color smart panels
7.2

Signals

See Table 7-1
Table 7-1. LCD Interface Signal List
Signal Name Type
LDD<17:0> Bidirectional
L_PCLK_WR Output
L_LCLK_A0 Output
L_FCLK_RD Output
L_BIAS Output
L_CS Output
L_VSYNC Input
Note: Not all signals are required for all modes of operation. Refer to the LCD panel reference
documentation specific to the manufacturer for information on:
•
Specific signals required for correct LCD operation
•
Correct names of the signals used by the LCD panel manufacturer
II:7-2
for the list of LCD interface signals of the PXA27x processor.
Data lines used to transmit 4-, 8-, 16-, or 18-data values at a time to the LCD display module.
Not all panels require all data lines for operation. Consult the panel manufacturer's
documentation.
LDD<7:0> are used to as input data bus during reads to the smart panels.
Pixel clock used by the LCD display module to clock the pixel data into the panel. Write signal
for writing to smart panels.
For passive (STN) displays, the line clock used by the LCD display module signals the end of a
line of pixels. Used by active (TFT) displays as the horizontal synchronization signal.
This control signal specifies command or data transactions when interfacing with smart panels.
For passive (STN) displays, the frame clock used by the LCD display module signals the start
of a new frame of pixels. Used by active (TFT) display module as the vertical synchronization
signal.
Read signal during reads to the smart panels.
For passive (STN) displays, the AC bias signals the LCD display module to switch the polarity
of the power supplies to the row and column axis of the screen to counteract DC offset. In
active (TFT) mode, the AC bias is used as the output-enable to signal when data is latched
from the data pins using the pixel clock.
For smart panels, this pin is used as chip-select signal. No connect for active (TFT) and passive
(STN) panels.
Refresh sync signal from smart panels. No connect for active (TFT) and passive (STN) panels.
Description
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Intel PXA27x Processor Family Design Guide