CDC-200/300 (Customizable Display Controllers) - Overview

CDC-200 and CDC-300 are fully customizable display controller IPs supporting the OpenWF display API specification.
CDC-200 and CDC-300 are fully customizable display controller IPs supporting the OpenWF display API specification.

DC-200 and CDC-300 are fully customizable display controller IPs supporting the OpenWF display API specification. A number of features can be configured both at synthesis time and at run time. In this way the display controller can be adapted to both, FPGA systems (limited features, special applications) or for an ASIC (generic feature set, more flexibility). At compile time, the most important features that can be configured are supported input formats, number of layers, alpha blending technique and (for CDC-300) the scaling option. The maximum number of input layers only depends on the bus bandwidth and timing constraints. CDC-200/300 can support AMBA APB and AHB/AXI as well as the Altera AVALON bus interface. The controller provides a digital RGB signal with video data and signals for horizontal/vertical blank and synchronization as output. To support a large number of displays, resolution and refresh rate can be register controlled.

Download CDC-200 product brief

Download CDC-300 product brief


CDC-200/300 Highlights

  • Configurable number of layers and layer-composition/blending suppor
  • - GUI on top of HMI
    - High Resolution support upto 65536 x 65536
  • Windowing
  • - Picture-in-Picture
    - Video overlay
  • Flexible color format handling
  • - RGB565, ARGB8888 etc.
  • Gamma Correction
  • - Using independent look-up tables for R,G,B
  • Dithering
  • - For outputs with low bits per channel
  • Configurable alpha blending modes
  • - Resource usage vs. flexibility
  • Compile time parameterization
  • - Allows to tailor resource usage to real system needs
  • Support for dual-view displays
  • Video streaming mode
  • Simple to use API


CDC-300 Highlights

  • Option for YUV input formats in addition to (A)RGB formats
  • Option for scaling of input layers
  • Horizontal and vertical mirroring of framebuffer possible



CDC Architecture

Configurable Features

Feature Description
Multiple Layers Support for a variable amount of layers and input formats
Alpha-Layer Ability to store alpha-values for layers in separate Alpha-Layers
Windowing Each layer can have an individual size and position
Variable Resolution and Refresh Rate Support for resolutions up to 65536x65536 at different refresh rates
Variable Resolution and Refresh Rate (Runtime) Ability to change resolution and refresh rate at runtime
Gamma Correction Correct gamma via a configurable Gamma Ramp
Vertical IRQ Raise an IRQ if the end of a frame is reached
Background Colour Ability to specify a custom background colour
Blending Techniques Provide several techniques of alpha blending
Variable pixel-formats The output pixel-format can be adjusted
Dithering Ability for dithering
Scaling of input layers CDC-300 only
Horizontal or vertical mirroring CDC-300 only


Supported Pixel Format (selection)

In general all formats which encode (A)RGB in 8,16 or 32 bits can be configured. At run-time, a set of up to 8 formats can be defined.

Format Description
8888 32 bit ARGB, alpha channel optional
4444 16 bit ARGB, alpha channel optional
1555 16 bit ARGB, alpha channel optional
565 16 bit RGB, no additional alpha channel
8 8 bit Greyscale, can be used as alpha-values


Supported Blending Techniques

Supported Blending Techniques

Technique Description
Simplified Blending Simplified calculation: Division by 256 instead of 255. Correction for alpha-values of 255.
Precise Blending Division by 255 (MulDiv255). Correct results


In general the formula for alpha blending two layers (i.e. Layer0 and Layer1) is:

ColourRes = f1 * colour1 + f0 * colour0

Colour1 is the colour of the top layer, colour0 of the subjacent layer. The factors f1 and f0 are alpha values. The blending mode describes which alpha values to use for f1 and f0. For both of the parameters an own blending mode can be chosen. The information of the blending mode is stored in the upper layer (in this case Layer1). The alpha values are stored in the upper layer (a1) and in the subjacent layer (a0).


Gamma Ramp

Gamma ramp is for gamma correction. All output pixels are forwarded to it unless the ramp is deactivated. The ramp consists of three lookup tables, one for each colour. Input colours are used as an address to the gamma-corrected value.


For More Information

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Evaluation Kits

CDC is included in the following Eval Kits:

Download D/AVE 2D + CDC-200 Evaluation Kit 3.0 Altera Edition

Download D/AVE HD + Graphics IP Evaluation Kit 1.0 Altera Edition (2014-01-24)


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