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NXP Semiconductors
PNX15xx/952x Series
Volume 1 of 1
Chapter 20: 2D Drawing Engine
PNX15XX_PNX952X_SER_N_4
NXP B.V. 2007. All rights reserved.
Product data sheet
Rev. 4.0 — 03 December 2007
20-622
4. Source data is provided by the processor via the MMIO bus and is a
monochrome text font.
5. Source data is provided by the processor via the MMIO bus and is Alpha
Blending data.
Option 1 is used for normal screen-to-screen operations such as a source-to-
destination copy. Option 2 is used for a host-to-screen copy when the source data is a
full color bitmap. Option 3 is used for color expanding a monochrome bitmap. The
monochrome bitmap will be expanded to full color using the foreground and
background color registers within the drawing engine. Option 4 is similar to Option 3
except that it is designed to handle tightly packed fonts, which are used to render text.
A three-bit eld is used to select the appropriate source data option. Option 5 is
similar to Option 2 except that the data provided on the MMIO bus is either packed
4 bit alpha or packed 8-bit alpha information.
2.3.4
Patterns
The drawing engine provides an 8-by-8 pattern or “brush.” The pattern is always
locked to the screen. This pattern can be solid, monochrome, or full color. If the
pattern is solid, the color value will be taken from the foreground color register. A
monochrome pattern is stored in system memory as two DWORDs (64 bits) of
monochrome data. This monochrome data is written to the drawing engine where it is
color expanded to the appropriate color depth and stored in the pattern RAM. A full
color pattern will be directly transferred from system memory into the pattern RAM.
Only one pattern may be stored in the pattern RAM at a given time.
2.3.5
Transparency
The drawing engine supports transparency on either source or destination data.
Transparent patterns are not supported. Transparency works by comparing either
source or destination to a value stored in a color compare register and then allowing
(or disallowing) a write to occur based on the result of the compare. Transparency is
implemented on a per-pixel basis: at 8 bpp one byte is used for the compare value. At
16 bpp one word is used for the compare, and at 32 bpp the entire color compare
register is used for the compare. A transparency mask is provided in order to exclude
certain bits within a pixel from being used in the color compare.
2.3.6
Block Writes
Block writes are not supported by the drawing engine.
3.
Operation
3.1 Register Programming Guidelines
3.1.1
Alpha Blending
The drawing engine supports alpha blending of Source, Destination, and a global
SurfaceAlpha. The following destination formats are useful with alpha blending:
RGB:565(16 bit per pixel)
αRGB:4444(16 bit per pixel)