
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
20-620
2.2.12
Bit BLT Engine
This is the main control logic for bit BLT commands. This block breaks BLTs down into
appropriate subcommands such as SRC read, DST write, etc. and then sequences
through those subcommands.
2.2.13
Vector Engine
This is the main control for line commands. This block contains the Bresenham
engine.
2.2.14
Memory Interface
This block handles the interface to the DVP memory highway gizmo.
2.2.15
Byte Masking
This block combines bit BLT or vector byte mask information and transparency
information to generate the byte enables for the MTC. This block also generates the
block write masks.
2.3 General Operations
The Drawing Engine supports two types of operations: lines and bit BLTs. Line
capability is limited to solid lines, with the software responsible for the calculation of
the initial error terms of the Bresenham algorithm. Lines are provided as a
compatibility check mark and are not highly optimized.
Bit BLTs are the primary function of the drawing engine and are highly optimized for
performance. Bit BLT is the generic term used to indicate the transfer and processing
of a block of visual data from one location to another. To specify the type of bit BLT,
the following information is required:
Raster Operation (ROP): of 256 possible ROPs
Alpha Blend Mode: Source or Surface
Source data location and type: system memory or CPU, mono, color, or alpha
Transparency: On Source, On Destination, or none
Pattern: 8 X 8 mono, 8 X 8 color, or solid
2.3.1
Raster Operations
The Drawing Engine supports a three operand bit BLT. The three operands are
source, destination, and pattern. There are eight logical operations that can be
performed with any combination of the three operands: one, zero, and, or, nand, nor,
xor, nxor. This yields a total of 256 combinations of ROP that can be performed.
Although all 256 ROPs are possible, only a handful of these ROPs are typically used.
Examples of a single operand BLT would be a pattern ll or a basic screen-to-screen
copy where the source overwrites the destination. An example of a two operand BLT
is the source is “xor’d” with the destination. A three operand BLT could “and” the
source, pattern, and destination. The raster operation is dened by an 8-bit eld
specifying one of the possible 256 operations.