Texas Instruments TMS320C64x DSP Benutzerhandbuch

4-47

In order to display video in the BT.656 or Y/C format, the following steps are
needed:

1) Set the frame size in VDFRMSZ. Set the number of lines per frame

(FRMHIGHT) and the number of pixels per line (FRMWIDTH).

2) Set the horizontal blanking in VDHBLNK. Specify the frame pixel counter

value where horizontal blanking starts (HBLNKSTART) and pixel location
where horizontal blanking stops (HBLNKSTOP).

3) Set the V bit timing for field 1 in VDVBIT1. Specify the line where the V bit

is set (VBITSET1) and the line where the V bit is cleared (VBITCLR1).

4) If external VBLNK signal is needed, set the VBLNK start for field 1 in

VDVBLKS1. Specify the frame line (VBLNKYSTART1) and frame pixel
counter (VBLNKXSTART1) values for the pixel where VBLNK goes active
for field 1. Set the VBLNK end for field 1 in VDVBLKE1. Specify the frame
line (VBLNKYSTOP1) and frame pixel counter (VBLNKXSTOP1) values
for the pixel where VBLNK goes inactive for field 1.

5) Set the V bit timing for field 2 in VDVBIT2. Specify the line where the V bit

is set (VBITSET2) and the line where the V bit is cleared (VBITCLR2).

6) If external VBLNK signal is needed, set the VBLNK start for field 2 in

VDVBLKS2. Specify the frame line (VBLNKYSTART2) and frame pixel
counter (VBLNKXSTART2) values for the pixel where VBLNK goes active
for field 2. Set the VBLNK end for field 2 in VDVBLKE2. Specify the frame
line (VBLNKYSTOP2) and frame pixel counter (VBLNKXSTOP2) values
for the pixel where VBLNK goes inactive for field 2.

7) Set VDIMGSZn. Adjust the displayed image size by setting the HSIZE and

VSIZE bits.

8) Set VDIMOFF. Adjust the displayed image offset within the active video

area (by setting HOFFSET and VOFFSET).

9) Set the F bit timing in VDFBIT. Specify the line where the F bit is cleared

(FBITCLR) and the line where the F bit is set (FBITSET).

10) If external FLD output is required, set the video display field 1 timing.

Specify the line and pixel where FLD goes inactive (VDFLDT1). Set the
video display field 2 timing. Specify the line and pixel where FLD goes
active (VDFLDT2).

11) Set VDCLIP. Default values for video clipping are 16 for the lower clipping,

235 for the higher clipping of the Y values, and 240 for the higher clipping
of the Cb and Cr values.