bt829bkrf ETC-unknow, bt829bkrf Datasheet - Page 41

• Manufacturer Part Number: bt829bkrf
• Description: Video Streamii Decoders
• Manufacturer: ETC-unknow

Bt829B/827B
VideoStream II Decoders
rate (the CLKx1 rate) in each of these regions is as follows:
tion becomes:
Vertical Delay Register (VDELAY)
between the rising edge of VRESET and the start of active video lines. It deter-
mines how many lines to skip before initiating the ACTIVE signal. It is pro-
grammed with the number of lines to skip at the beginning of a frame.
Vertical Active Register (VACTIVE)
of lines used in the vertical scaling process. The actual number of vertical lines
output from the Bt829B is equal to this register times the vertical scaling ratio. If
VSCALE is set to 0x1A00 (4:1), then the actual number of lines output is
VACTIVE/4. If VSCALE is set to 0x0000 (1:1), then VACTIVE contains the
actual number of vertical lines output.
NOTE:
HDELAY = [(CLKx1_HDELAY / CLKx1_HACTIVE) * HACTIVE] & 0x3FE
PAL/SECAM
When cropping is not implemented, the number of clocks at the 4x sample
The value for HDELAY is calculated using the following formula:
CLKx1_HDELAY and CLKx1_HACTIVE are constant values, so the equa-
In this equation, the HACTIVE value cannot be cropped.
NTSC
NTSC: HDELAY = [(135 / 754) * HACTIVE] & 0x3FE
PAL/SECAM: HDELAY = [(186 / 922) * HACTIVE] & 0x3FE
It is important to note the difference between the implementation of the
horizontal registers (HSCALE, HDELAY, and HACTIVE) and the vertical
registers (VSCALE, VDELAY, and VACTIVE). Horizontally, HDELAY
and HACTIVE are programmed with respect to the scaled pixels defined
by HSCALE. Vertically, VDELAY and VACTIVE are programmed with
respect to the number of lines before scaling (before VSCALE is applied).
Front Porch
CLKx1
21
27
D829BDSA
1.7 Video Scaling, Cropping, and Temporal Decimation
VDELAY is programmed with the delay
HDELAY
VACTIVE is programmed with the number
CLKx1
135
186
HACTIVE
CLKx1
1.0 Functional Description
754
922
CLKx1
Total
1135
910
31