AMD Geode LX 800@0.9W - Manual (Page 471)

AMD Geode™ LX Processors Data Book 471
Video Input Port 33234H
6.9.8 BT.601 Mode
BT.601 mode allows reception of 8- or 16-bit video input
which consists of HSYNC, VSYNC, and 8/16 bit data. Verti-
cal and horizontal start/stop registers provide the informa-
tion for data capture in each field/frame. The BT.656 SAV/
EAV codes (if present) are ignored. Frame/line timing is
derived from the HSYNC and VSYNC inputs only. Odd/
even field is determined by the leading edges of VSYNC
and HSYNC. Default field detection is shown in Figure 6-
45. A detection window is programmable using the VIP
Memory Offset 50h. If the leading edge of VSYNC occurs
within the window, the field is odd. If the leading edge of
VSYNC occurs outside the window, the field is even. The
VIP Memory Offset 50h default value requires that the
HSYNC and VSYNC leading edges occur simultaneously
for odd field detection (see Figure 6-46 on page 472). The
horizontal and vertical input timings of the input video
frame are also programmable. See Figure 6-47 and Figure
6-48.
Figure 6-45. BT.601 Mode Default Field Detection
HSYNC
VSYNC
ACTIVE LOW HSYNC/VSYNC (HSYNC polarity = 0 / VSYNC polarity = 0)
ACTIVE HIGH HSYNC/VSYNC (HSYNC polarity = 1 / VSYNC polarity = 1)
VSYNC
HSYNC
(for odd field)
(for even field)
even field
odd field
line #1
line #1
even field
odd field (line #1)
(line #1)
even field (line #2)
odd field (line #2)
VSYNC
VSYNC
(for odd field)
(for even field)
even field
odd field even field
odd field (line #1)
(line #1)
even field (line #2)
odd field (line #2)
Odd field is indicated when leading edge of VSYNC and the leading edge of HSYNC occur simultaneously
(VIP allows for a programmable detection window for odd field).
Even field is indicated when leading edge of VSYNC occurs prior to the leading edge of HSYNC.