MB86290A "Cremson" is a 2D/3D graphics controller optimized for applications in car navigation systems and mobile
information processing terminals. Adopting various sophisticated functions, such as flat or Gouraud shading,
bilinear texture mapping, and Z-buffering, Cremson delivers high-speed and superior-performance 3D graphics
functionality.
Moreover, anti-aliasing, concaved polygon rendering and fast line draw features are also included, allowing smooth
and sophisticated-quality rendering. As a result, Cremson performs high-quality rendering operations, with similar
quality to leading-edge PC graphics, but with lower power dissipation. Cremson supports a 64-bit wide external memory
interface. This interface is driven at the same 100MHz frequency as its internal operation to support the
large-memory bus bandwidth that is needed to perform the high-performance graphics operations described above. Also,
in order to support various kinds of system configurations, Cremson offers a configurable host interface for four
types of CPUs (Fujitsu FR30, Hitachi SH3/4, and NEC V832) without external glue logic.
To address the especially complex window configurations of car navigation systems. Cremson offers 4 layers of overlay
planes. These layers are (from top to bottom): C (console) layer, W (window) layer, M (middle) layer and B (base) layer.
All layers can be rendered in 16-bit/pixel colour (65.536 colours displayed at a time) or rendered in 8-bit indirect
colour mode (256 selected out of 262.144 colours). The colour palette can be defined separately to the C layer and B
and M layers. A transparent colour option is used to blend the layers directly.
Layer concept
For screen separation in wide-screen displays, the M and B layers can be split into two separate segments
(left and right). This feature is useful when two different reduced map scales are displayed side by side.
Of course, all these layers and segments can be scrolled independently. Two hardware cursors are supported in addition.
An "alpha-flag" per pixel is supported for the C-layer. This feature is useful for blending the C layer
colour with all the layer contens below, providing a variable transparent colour effect ("alpha-blending").
Cremson consists of 4 block modules: host interface block, external memory interface block, display control block,
and 2D/3D rendering block. These modules are connected by an internal 64-bit bus called ''Pixel bus''.
Also, the host interface block is connected to each of the other 3 blocks independently to avoid display
and/or rendering operations when the host CPU attempts to access these modules.
Cremson Block Diagram
|
 |
CMOS 0.25 µm technology
|
|
Display resolutions up to 1024x768
|
|
4 layers of overlay display (bottom 2 layers are both split into separate segments)
|
|
RGB analog output (high speed DAC)
|
|
Includes various kinds of 2D/3D graphic acceleration functions
|
|
Built-in alpha blending, anti-aliasing and chroma-keying
|
|
Up to 32 MB external graphic memory (SDRAM) 64 bit wide @ 100 MHz
|
|
Configurable CPU-interface for FR30, SH3, SH4, V83x CPUs
|
|
Supply voltage 3.3V (I/O), 2.5V (Internal)
|
|
QFP-240 Package
|
|
Temperature range -40..+85 °C
|
|
