Cirrus Logic EP93xx - Manual (Page 217)

DS785UM1 7-35
Copyright 2007 Cirrus Logic
Raster Engine With Analog/LCD Integrated Timing and Interface
EP93xx User’s Guide
7
7
7
1. The MSB is dropped
2. The remaining bits are shifted left by one
3.The LSB is set to ‘1’
1110 - Dim 888 Blinking:
The 24 bits of data is made up of three 8-bit values that represent the RGB colors. Each
of the 8 bit values is treated as a single value, and the blinking rules defined for the Dim
Single Blinking mode are applied.
1111 - Bright 888 Blinking:
The 24 bits of data is made up of three 8-bit values that represent the RGB colors. Each
of the 8 bit values is treated as a single value, and the blinking rules defined for the
Bright Single Blinking mode are applied.
7.4.12 Color Mode Definition
One of four modes may be selected to define pixel color: Pixel Look-Up Table Mode, Triple 8-
Bit Mode, 16-Bit 565 Mode, and 16-Bit 555 Mode.
7.4.12.1 Pixel Look-up Table Mode
The Raster Engine contains a 256 x 24 bit RAM that is used as pixel look-up-table (LUT) for
pixel depths up to 8-bits. Appropriate blink operations, if any, are performed on the pixel data
fetched from the video memory and the resulting pixel data value is used as an index into the
LUT. The pixel value located at the index position continues through the video pipeline.
The LUT is memory mapped and may be written at any time. However, if it is written during a
non-blanking interval, the display may be momentarily corrupted.
Writing 0x0 to the C[3:0] bits (color bits) in the PixelMode register to 0x0 enables the LUT.
7.4.12.2 Triple 8-bit Color Definition Mode
The 24 bits of data is divided into three color planes, where the RED, GREEN, and BLUE
each have 8 bits of color definition.
7.4.12.3 16-bit 565 Color Definition Mode
The 16 bits of data is divided into three color planes, where the RED and BLUE each have 5
bits for color definition and the GREEN has 6 bits for color definition.
7.4.12.4 16-bit 555 Color Definition Mode
The 16 bits of data is divided into three color planes, where the RED, GREEN, and BLUE
each have 5 bits of color definition. The MSB of the 16-bit data is not used.