10
BLANK AND DVALID TIMING
DVALID is asserted when P15-P0 contain valid data. The
timing and behavior of DVALID is dependent on the output
video format and the programmed values for bit 4
(DVLD_DCYC) and bit 5 (DVLD_LTC) of the GENLOCK
CONTROL register 04
H
. Refer to the specific output video
format sections that follow for the specific behavior for
DVALID.
BLANK is used to determine if the HMP8116 is generating
active video data. BLANK should be used in conjunction with
DVALID to capture digital data from the decoder. BLANK,
DVALID and the video data are output after the internal pipe-
line latency and synchronous with the rising edge of CLK2.
During active scan lines BLANK is negated when the hori-
zontal pixel count matches the value in the END H_BLANK
register 32
H
. A count of 00
H
corresponds to the 50% point of
the leading edge of the sync tip after leaving the part.
BLANK is asserted when the horizontal pixel count matches
the value in the START H_BLANK register 31
H
/30
H
. Note
that horizontally, BLANK is programmable with two pixel res-
olution.
START V_BLANK register 34
H
/33
H
and END V_BLANK reg-
ister 35
H
determine which scan lines are blanked for each
field. During inactive scan lines, BLANK is asserted during the
entire scan line. Half-line blanking of the output video cannot
be done. Reference Figure 8 for active video timing and use
Table 2 for typical blanking programming values
NOTE:
6. The trailing edge of VSYNC is 5
±
1 clocks after the leading edge of HSYNC to be VMI compatible and to indicate a transition to an even field.
FIGURE 7. PAL(B,D,G,H,I,N,N
C
) HSYNC, VSYNC AND FIELD TIMING DURING AN ODD TO EVEN FIELD TRANSITION
VIDEO
INPUT
VSYNC
FIELD
‘ODD’ FIELD
‘EVEN’ FIELD
HSYNC
311
LINE #
312
313
314
315
316
317
318
319
320
310
309
TABLE 2. TYPICAL VALUES FOR HBLANK AND VBLANK REGISTERS
VIDEO STANDARD
(MSB/LSB)
ACTIVE
PIXELS/
LINE
TOTAL
PIXELS/
LINE
LAST
PIXEL
COUNT
START
H_BLANK
(31H/30H)
END
H_BLANK
(32H)
START
V_BLANK
(34H/33H)
END
V_BLANK
(35H)
RECTANGULAR PIXELS
NTSC (M), PAL (M)
PAL (B, D, G, H, I,N, N
C
)
720
720
858
864
857 (0359
H
)
863 (035F
H
)
842 (034A
H
)
852 (0354
H
)
122 (7A
H
)
132 (84
H
)
259 (0103
H
)
310 (0136
H
)
19 (13
H
)
22 (16
H
)
SQUARE PIXELS
NTSC (M), PAL (M)
PAL (B, D, G, H, I,N, N
C
)
640
768
780
944
779 (030B
H
)
943 (03AF
H
)
758 (02F6
H
)
922 (039A
H
)
118 (76
H
)
154 (9A
H
)
259 (0103
H
)
310 (0136
H
)
19 (13
H
)
22 (16
H
)
HMP8116