ADV7181 AD [Analog Devices], ADV7181 Datasheet - Page 38

• Manufacturer Part Number: ADV7181
• Description: Multiformat SDTV Video Decoder
• Manufacturer: AD [Analog Devices]

ADV7181B
SYNCHRONIZATION OUTPUT SIGNALS
HS Configuration
The following controls allow the user to configure the behavior
of the HS output pin only:
•
•
•
The HS Begin and HS End registers allow the user to freely
position the HS output (pin) within the video line. The values in
HSB[10:0] and HSE[10:0] are measured in pixel units from the
falling edge of HS. Using both values, the user can program
both the position and length of the HS output signal.
HSB[10:0] HS Begin, Address 0x34 [6:4], Address 0x35 [7:0]
The position of this edge is controlled by placing a binary
number into HSB[10:0]. The number applied offsets the edge
with respect to an internal counter that is reset to 0 immediately
after EAV code FF,00,00,XY (see Figure 19). HSB is set to
00000000010b, which is 2 LLC1 clock cycles from count[0].
The default value of HSB[10:0] is 0x002, indicating that the HS
pulse starts 2 pixels after the falling edge of HS.
Table 53. HS Timing Parameters (see Figure 19)
Standard
NTSC
NTSC Square Pixel
PAL
PIXEL
LLC1
BUS
HS
Beginning of HS signal via HSB[10:0]
End of HS signal via HSE[10:0]
Polarity of HS using PHS
ACTIVE
VIDEO
D
Cr
E
Y
FF
HS Begin Adjust
(HSB[10:0])
(default)
00000000010b
00000000010b
00000000010b
00
4 LLC1
EAV
00
HSE[10:0]
XY
80
HS End Adjust
(HSE[10:0])(default)
00000000000b
00000000000b
00000000000b
10
HSB[10:0]
80
10
H BLANK
80
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Figure 19. HS Timing
10
C
HS to Active Video (LLC1
Clock Cycles)
(C in Figure 19) (default)
272
276
284
Characteristic
HSE[10:0] HS End, Address 0x34 [2:0], Address 0x36 [7:0]
The position of this edge is controlled by placing a binary
number into HSE[10:0]. The number applied offsets the edge
with respect to an internal counter that is reset to 0 immediately
after EAV code FF,00,00,XY (see Figure 19). HSE is set to
00000000000b, which is 0 LLC1 clock cycles from count[0].
The default value of HSE[10:0] is 000, indicating that the HS
pulse ends 0 pixels after falling edge of HS.
For example:
1.
2.
To move 20 LLC1s away from active video is equal to subtracting
20 from 1716 and adding the result in binary to both HSB[10:0]
and HSE[10:0].
PHS Polarity HS, Address 0x37 [7]
The polarity of the HS pin can be inverted using the PHS bit.
When PHS is 0 (default), HS is active high.
When PHS is 1, HS is active low.
FF
To shift the HS toward active video by 20 LLC1s, add 20
LLC1s to both HSB and HSE, i.e., HSB[10:0] =
[00000010110], HSE[10:0] = [00000010100].
To shift the HS away from active video by 20 LLC1s, add
1696 LLC1s to both HSB and HSE (for NTSC), that is,
HSB[10:0] = [11010100010], HSE[10:0] = [11010100000].
1696 is derived from the NTSC total number of Pixels =
1716.
E
00
SAV
00
XY
Cb
Active Video
Samples/Line
(D in Figure 19)
720Y + 720C = 1440
640Y + 640C = 1280
720Y + 720C = 1440
Y
Cr
ACTIVE VIDEO
Y
D
Cb
Y
Total LLC1
Clock Cycles
(E in Figure 19)
1716
1560
1728
Cr