LCD Controller

In active color display mode, the LCD controller can drive TFT displays. When using 1-, 2-, 4-, or 8-bit modes, the LCD’s dither logic is bypassed, and the pixel value is sent from the palette buffer directly to the LCD’s data output pins. 16-bit pixel mode bypasses both the palette and the dither logic.

7.1.1Features

The processor LCD controller supports the following features:

Display modes:

single- or dual-panel displays

up to 256 gray-scale levels (8 bits) in Passive Monochrome Mode

a total of 65536 possible colors in Passive Color Mode (using the 16-bit TMED dithering algorithm)

up to 65536 colors in Active Color Mode (16 bits, bypasses palette)

passive 8-bit color single-panel displays

passive 8-bit (per panel) color dual-panel displays

Display sizes up to 1024x1024 pixels, recommended maximum of 640x480

Internal color palette RAM 256 entry by 16 bits (can be loaded automatically at the beginning of each frame)

Encoded pixel data of 1, 2, 4, 8, or 16 bits

Programmable toggle of AC bias pin output (toggled by line count)

Programmable pixel clock from 195 kHz to 83 MHz (100 MHz/512 to 166 MHz/2)

Integrated 2-channel DMA (one channel for palette and single panel, the other channel for second panel in dual-panel mode).

Programmable wait-state insertion at the beginning and end of each line

Programmable polarity for output enable, frame clock, and line clock

Programmable interrupts for input and output FIFO underrun

Programmable frame and line clock polarity, pulse width, and wait counts

7-2

Intel® PXA255 Processor Developer’s Manual

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Intel PXA255 manual Features, LCD Controller