FS401LF ETC2 [List of Unclassifed Manufacturers], FS401LF Datasheet - Page 18

• Manufacturer Part Number: FS401LF
• Description: PC to TV Video Scan Converters
• Manufacturer: ETC2 [List of Unclassifed Manufacturers]

FS401, FS403
4.2 Internal Micro-Controller Programming
4.2.1 Input Calibration
The internal micro-controller needs to know what portion of the input video signal contains active video.
Determining this information is referred to as Input Calibration. The input calibration information is used
by the internal micro-controller to calculate the low-level registers that scale the input image to fit on the
output device.
The internal micro-controller stores the input calibration information as 4 ratios that describe the active
video area in relation to the total input video signal. These 4 ratios are:
For example, if the input video signal has 1138 pixel times from HSync to HSync, only 1024 of the pixels
are active, and the first active pixel is at pixel time 57, then SHV and HAT would be:
There are two methods of determining the input calibration: auto input calibration and manual input
calibration. Additionally, the internal micro-controller can store the input calibration for 4 video modes.
4.2.1.1 Auto Input Calibration
When the FS400 is in auto input calibration mode, then the internal micro-controller will use the active
video registers (SHV, EHV, SVV, and EVV) to determine the input calibration. The internal micro-
controller will sample the active video registers until their values stabilize for at least 600 milliseconds.
The internal micro-controller will wait up to 3 seconds for the active video registers to stabilize. If the
active video register do not stabilize, the internal micro-controller will revert to the default input calibration
information to display the image. Additionally, if the input calibration values calculated from the active
video registers are outside of the minimums and maximums allowed, the internal micro-controller will
revert to the default input calibration information. The internal micro-controller will continue to sample the
active video registers. If the registers do stabilize at a later time, the default input calibration will be
replaced with the calculated input calibration.
After the initial input calibration is acquired, the internal micro-controller continues to sample the active
video registers. If the input calibration calculated from the new sample indicates a larger active video
area, then the new input calibration is used.
Auto input calibration is enabled by clearing the DSICAL bit in the SCR register. This is the default mode
of operation. There is nothing else an external controller need to do to allow automatic calibration to
work. However, an external controller can modify the behavior of auto input calibration by changing the
following configuration values via the CCR and CDR registers.
JANUARY 24, 2007
SHV
HAT
SVV
VAT
SHV = 57 / 1138 * 65536
HAT = 1024 / 1138 * 65536
CCR_DEF_SHV
CCR_MIN_SHV
CCR_MAX_SHV
CCR_DEF_HAT
CCR_MIN_HAT
(Number of pixel times from HSync to the start of the active video) / (The total pixel times
from HSync to HSync) * 65536
(Number of active pixels) / (The total pixel times from HSync to HSync) * 65536
(Number of lines from VSync to the start of the active video) / (The total lines from VSync to
VSync) * 65536
(Number of active lines) / (The total lines from VSync to VSync) * 65536
Default Start of Horizontal Video
Minimum Start of Horizontal Video
Maximum Start of Horizontal Video
Default Horizontal Active
Minimum Horizontal Active
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COPYRIGHT © 1999 FOCUS ENHANCEMENTS, INC.
PRODUCT SPECIFICATION
REV. NO. 1.7