Texas Instruments TMS320DM648 manual Video Display Mode Selection, Image Timing

Models: TMS320DM648

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Video Display Mode Selection

4.1Video Display Mode Selection

The video display module operates in one of three modes as listed in Table 4-1. The DMODE bits are in the video display control register (VDCTL). The Y/C and 16-bit raw display modes may only be selected if the DCDIS bit in the video port control register (VPCTL) is cleared to 0.

Table 4-1. Video Display Mode Selection

DMODE Bits

Mode

Description

000

8-Bit ITU-R BT.656 Display

Digital video output is in YCbCr 4:2:2 with 8-bit resolution multiplexed in ITU-R

 

 

BT.656 format.

010

8-Bit Raw Display

8-bit data output

100

8-Bit Y/C Display

Digital video is output in YCbCr 4:2:2 with 8-bit resolution on parallel Y and

 

 

Cb/Cr multiplexed channels.

110

16-Bit Raw Display

16-bit data output.

4.1.1 Image Timing

Display devices generate interlaced images by controlling the vertical retrace timing. The video display module emits a data stream used to generate a displayed image. An NTSC-compatible interlaced image with field and line information is shown in Figure 4-1. A progressive-scan image (SMPTE 296M compatible) is shown in Figure 4-2.

The active video area represents the pixels visible on the display. The active video area begins after the horizontal and vertical blanking intervals. The image area output by the video display module can be a subset of the active area. The relationship between frame, active video area, and image area is presented in Figure 4-3for interlaced video and in Figure 4-4for progressive video. The video display module generates timing for frames, active video areas within frames, and images within the active video area.

Figure 4-1. NTSC Compatible Interlaced Display

Field 1

Line 20

Line 21

Line 22

Line 261

Line 262

Line 263

Field 2

Line 282

Line 283

Line 284

Line 523

Line 524

Line 525

SPRUEM1 –May 2007

Video Display Port

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Texas Instruments TMS320DM648 manual Video Display Mode Selection, Image Timing, Dmode Bits Mode Description