PRODUCT SPECIFICATION
TMC22x5yA
STS: The number of pixels between sync pulses
Table 20. Table of Line Idents, LID[4:0] (cont.)
Line no:
260 & 261
262
LID
4-0
STB: The number of pixels between the nominal mid point
of sync and the start of the 16 pixel burst gate. This value is
modified depending upon the mode of operation.
10
11
12
13
14
15
16
17
263 - 307
308
Table 21. Timing Offsets
Standard
Mode
Genlock
Offset required
309
x
-8
-8
310
x
x
Line locked
Subcarrier
D2 mode
D2 mode
D1 mode
311
-22
-12
-8
312
PAL
NTSC
x
Timing Parameters
+12
Subcarrier Programming
BTV: The number of pixels between the start of the 16 pixel
burst gate and the nominal start of active video.
The color subcarrier is produced by an internal 28 bit Direct
Digital Synthesizer (DDS) which is phase locked to the burst
signal of the digitized video input. The nominal frequency is
programmed into the DDS as follows:
AV: The number of active pixels in the active video line.
The difference between the sum of STB+BTV+AV sub-
tracted from STS provides the nominal front porch.
FREQ = (number of subcarrier cycles per line / number of
pixels per line) * 2^28
Horizontal and Vertical Timing Parameters
An example would be NTSC subcarrier mode
FREQ = (227.5 / 910) * 2^28 = 4000000 hex
When external horizontal and vertical syncs are provided the
timing shown in Figure 28 is required to synchronize the
internal state machines to beginning of a field (3, 5, or 7).
For field 2 (4, 6, or 8) the falling edge of VSYNC must occur
at least 2 clock periods but not more than (H-2) clock periods
after the falling edge of HSYNC, where H is the total num-
ber of pixels in an active video line.
Horizontal Timing
The horizontal video line is broken down into four horizontal
timing parameters.
STB
BTV
AV
STS
65-22x5y-68
Figure 27. Horizontal Timing
REV. 1.0.0 2/4/03
61
CADEKA [ CADEKA MICROCIRCUITS LLC. ]
