Texas Instruments TMS320C64x DSP 3 BT.656 Image Window and Capture, 010 011 100 101, P 0 Bits

BT.656 Video Capture Mode

Table 3–4. Error Correction by Protection Bits (Continued)

Received F, V, and H Bits

Received
	000	001	010	011	100	101	110	111
P3–P0Bits
0111	100	–	–	011	100	100	100	–
1000	000	–	–	–	–	101	110	–
1001	–	001	010	–	–	–	–	111
1010	–	101	010	–	101	101	–	101
1011	010	–	010	010	–	101	010	–
1100	–	001	110	–	110	–	110	110
1101	001	001	–	001	–	001	110	–
1110	–	–	–	011	–	101	110	–
1111	–	001	010	–	100	–	–	–

3.2.3BT.656 Image Window and Capture

The BT.656 format is an interlaced format consisting of two fields. The video port allows capture of one or both fields. The captured image is a subset of each field and can be larger or smaller than the active video region. The cap- tured image position is defined by the VCxSTRT1 and VCxSTOP1 registers for field 1, and the VCxSTRT2 and VCxSTOP2 registers for field 2. The VCXSTART and VCXSTOP bits set the horizontal window position for the field relative to the HCOUNT pixel counter. The VCYSTART and VCYSTOP bits set the vertical position relative to the VCOUNT line counter. This is shown in Figure 3–1.

HCOUNT increments on every chroma sample period (every other VCLKIN rising edge) for which capture is enabled. Once VCOUNT = VCYSTART, line capture begins when HCOUNT = VCXSTART. It continues until HCOUNT = VCXSTOP. A field’s capture is complete when HCOUNT = VCXSTOP and

VCOUNT = VCYSTOP.

3-6 Video Capture Port SPRU629