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Video Display Mode Selection

Figure 4-5shows how the horizontal blanking and horizontal synchronization signals are triggered. (HBLNK and HSYNC are shown active high).

Figure 4-5. Horizontal Blanking and Horizontal Sync Timing

FPCOUNT

718

719

720

 

735

736

 

799

800

 

857

0

1

 

 

 

 

 

 

 

 

 

 

 

 

 

HBLNK

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

HSYNC

FPCOUNT = HBLNKSTART

FPCOUNT = HBLNKSTOP

FPCOUNT = HSYNCSTOP

FPCOUNT = HSYNCSTART

The 12-bit FLCOUNT counts which scan line is being generated. The FLCOUNT is reset to 1 after reaching the count specified in VDFRMSZ. (For BT.656 operation, the FRMHIGHT would be set to 525 (525/60 operation) or 625 (625/50 operation).) The state of FLCOUNT is reflected in the VDYPOS bits of VDSTAT. Figure 4-6shows how the vertical blanking, vertical synchronization, and field identification signals are triggered. (VBLNK and VSYNC are shown active high.)

Note that the signals can transition at any place along the video line (specified by the XSTART and XSTOP bits of the appropriate registers). In this case, VBLNK starts at horizontal count VBLNKXSTART2 = 429 on scan line VBLNKYSTART2 = 263 (565/60 operation).

Figure 4-6. Vertical Blanking, Sync and Even/Odd Frame Signal Timing

 

 

 

 

 

 

 

 

 

 

 

 

One Line

 

 

One Frame

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FLCOUNT

5

6

7

 

 

18

19

20

 

 

263

264

265

266

 

267

268

 

269

270

 

282

283

284

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VBLNK

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FLCOUNT = VBLNKYSTOP1

FLCOUNT = VBLNKYSTART2

 

 

FLCOUNT = VBLNKYSTOP2

FPCOUNT = VBLNKXSTOP1

FPCOUNT = VBLNKXSTART2

 

 

FPCOUNT = VBLNKXSTOP2

VSYNC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FLCOUNT = VSYNCYSTOP1

 

FLCOUNT = VSYNCYSTART2

 

FLCOUNT = VSYNCYSTOP2

FPCOUNT = VSYNCXSTOP1

 

FPCOUNT = VSYNCXSTART2

 

FPCOUNT = VSYNCXSTOP2

524

525

1

2

3

4

5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FLCOUNT = VBLNKYSTART1

FPCOUNT = VBLNKXSTART1

FLCOUNT = VSYNCYSTART1 FPCOUNT = VSYNCXSTART1

FLD

 

Field 1

 

 

 

 

 

 

 

 

 

 

Field 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FLCOUNT = FLD2YSTART

 

 

FLCOUNT = FLD1YSTART

 

 

 

 

FPCOUNT = FLD2XSTART

 

 

FPCOUNT = FLD1XSTART

SPRUEM1 –May 2007

Video Display Port

97

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Texas Instruments TMS320DM648 manual Horizontal Blanking and Horizontal Sync Timing