Texas Instruments TMS320DM355 warranty Hardware 3A H3A

TMS320DM355

Digital Media System-on-Chip (DMSoC)

www.ti.com

SPRS463A –SEPTEMBER 2007 –REVISED SEPTEMBER 2007

5.9.1.3 Hardware 3A (H3A)

The H3A module is designed to support the control loops for Auto Focus, Auto White Balance and Auto Exposure by collecting metrics about the imaging/video data. The metrics are to adjust the various parameters for processing the imaging/video data. There are 2 main blocks in the H3A module:

∙Auto Focus (AF) engine

∙Auto Exposure (AE) Auto White Balance (AWB) engine

The AF engine extracts and filters the red, green, and blue data from the input image/video data and provides either the accumulation or peaks of the data in a specified region. The specified region is a two-dimensional block of data and is referred to as a "paxel" for the case of AF.

The AE/AWB Engine accumulates the values and checks for saturated values in a sub sampling of the video data. In the case of the AE/AWB, the two-dimensional block of data is referred to as a "window". Thus, other than referring them by different names, a paxel and a window are essentially the same thing. However, the number, dimensions, and starting position of the AF paxels and the AE/AWB windows are separately programmable.

The following features are supported by the AF engine:

∙Support for input from DDR2 / mDDR SDRAM (in addition to the CCDC port)

∙Support for a Peak Mode in a Paxel (a Paxel is defined as a two dimensional block of pixels).

∙Accumulate the maximum Focus Value of each line in a Paxel

∙Support for an Accumulation/Sum Mode (instead of Peak mode).

∙Accumulate Focus Value in a Paxel.

∙Support for up to 36 Paxels in the horizontal direction and up to 128 Paxels in the vertical direction. The number of horizontal paxels is limited by the memory size (and cost), while the vertical number of paxels is not. Therefore, the number of paxels in horizontal direction is smaller than the number of paxels in vertical direction.

∙Programmable width and height for the Paxel. All paxels in the frame will be of same size.

∙Programmable red, green, and blue position within a 2x2 matrix.

∙Separate horizontal start for paxel and filtering.

∙Programmable vertical line increments within a paxel.

∙Parallel IIR filters configured in a dual-biquad configuration with individual coefficients (2 filters with 11 coefficients each). The filters are intended to compute the sharpness/peaks in the frame to focus on.

The following features are supported by the AE/AWB engine:

∙Support for input from DDR2 / mDDR SDRAM (in addition to the CCDC port)

∙Accumulate clipped pixels along with all non-saturated pixels

∙Support for up to 36 horizontal windows.

∙Support for up to 128 vertical windows.

∙Programmable width and height for the windows. All windows in the frame will be of same size.

∙Separate vertical start co-ordinate and height for a black row of paxels that is different than the remaining color paxels.

∙Programmable Horizontal Sampling Points in a window

∙Programmable Vertical Sampling Points in a window

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