Texas Instruments TMS320C64x DSP Benutzerhandbuch

A-2

This is an example that explains how to configure the video port for 8-bit
BT.656 noncontinuous frame capture on channel A for 525/60 format. See
ITU–R BT.656-4 and video port specification (Figures 4–11, 4–33, 4–34, and
Table 4–37) for more details on 525/60 format.

/**********************************************************/
/* Capture parameter definitions based on 525/60 format   */
/**********************************************************/
#define VCA_HBLNK_SIZE

138 /* (858–720),horizontal blanking         */

    /* (EAV/SAV inclusive)                                              */
#define VCA_VBLNK1_SIZE

19  /* (20–1),v.blanking for field1          */

#define VCA_VBLNK2_SIZE

19  /* (283–264),v.blanking for field2       */

#define VCA_IMG_HSIZE1

720 /* field1 horizontal image size          */

#define VCA_IMG_VSIZE1

244 /* (263–20+1), fld1 vertical image size  */

#define VCA_IMG_HSIZE2

720 /* field2 horizontal image size          */

#define VCA_IMG_VSIZE2

243 /* (525–283+1), fld2 vertical image size */

/* Define field image sizes */
#define VCA_IMAGE_SIZE1

(VCA_IMG_HSIZE1 * VCA_IMG_VSIZE1)

#define VCA_IMAGE_SIZE2

(VCA_IMG_HSIZE2 * VCA_IMG_VSIZE2)

/* ––––––––––––––––––––––––––––––––––––––––––––––––––––––– */
/* Define channel A capture window co–ordinates for Field1 */
/* ––––––––––––––––––––––––––––––––––––––––––––––––––––––– */
/* HRST = 0, start of horizontal blanking */
#define VCA_XSTART1

(VCA_HBLNK_SIZE – 2/*EAV*/)

/* VRST = 1, end of vertical blanking */
#define VCA_YSTART1

1

#define VCA_XSTOP1

(VCA_XSTART1 + VCA_IMG_HSIZE1 – 1)

#define VCA_YSTOP1

(VCA_YSTART1 + VCA_IMG_VSIZE1 – 1)

/* ––––––––––––––––––––––––––––––––––––––––––––––––––––––– */
/* Define channel A capture window co–ordinates for Field2 */
/* ––––––––––––––––––––––––––––––––––––––––––––––––––––––– */
/* HRST = 0, start of horizontal blanking                  

*/

#define VCA_XSTART2

(VCA_HBLNK_SIZE – 2/*EAV*/)

/* VRST = 1, end of vertical blanking                      

*/

#define VCA_YSTART2

1

#define VCA_XSTOP2

(VCA_XSTART2 + VCA_IMG_HSIZE2 – 1)

#define VCA_YSTOP2

(VCA_YSTART2 + VCA_IMG_VSIZE2 – 1)

/* Define threshold values in double–words. Both fields should     */
/* same threshold value)                                           */
#define VCA_THRLD_FIELD1

(VCA_IMG_HSIZE1/8) /* line length in 

*/

#define VCA_THRLD_FIELD2

VCA_THRLD_FIELD1   /* double–words   

*/

/* Define number of events to be generated for field1 and field2   */
#define VCA_CAPEVT1

(VCA_IMAGE_SIZE1 / (VCA_VDTHRLD1 * 8))

#define VCA_CAPEVT2

(VCA_IMAGE_SIZE2 / (VCA_VDTHRLD2 * 8))

#define CAPCHA_FRAME_COUNT 5 /* in this example                 

*/