saa6713ah NXP Semiconductors, saa6713ah Datasheet - Page 53

• Manufacturer Part Number: saa6713ah
• Description: Xga Analog Input Flat Panel Controller
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Its coordinates are stored in eval_col_0 (x-coordinate) and
eval_row_0 (y-coordinate). All pixels are also compared
with the ref_colour_1 values. If one of the current colour
values is bigger, the coordinates are saved in eval_row_1
and eval_col_1. At the end this value defines the lower,
right corner of the active area. The values are kept in
eval_row_0/1 and eval_col_0/1 until another mode or
another area detection without resample is started. It is
also possible to start measuring with the preceded values
in the resample submodes. In submodes without
resample, the results will not be smaller than the preceding
values.
There are two different modes available:
The needed sample offsets for the input interface can be
directly obtained by reading out the eval_row_0 and
eval_col_0 values. The number of active pixels per line
and lines per field is generated by subtracting the
eval_row_0, eval_col_0 value from the eval_row_1,
eval_col_1 value.
Dependent on the sampling settings of the input interface,
the eval_row_0 and eval_col_0 values usually correspond
to the horizontal and vertical backporch of the incoming
video signal and the active video, of course, meets the
active area of that stream. The calculated active pixels per
line value can be used for adjusting the line-locked PLL
which is generating the ADC sample clock in a way that
this value matches the number of expected active pixels
per line in the actual graphics mode.
There are four submodes available, as shown in Table 32.
In the non-enhanced modes, the active area detection is
not performed over the whole frame as in the enhanced
modes, but only within the line and within the column
programmed by ref_row_0 and ref_col_0.
For correct results, these reference values have to be
previously set inside the active area of the picture. If a
submode with initial values is selected eval_col_0/1 and
eval_row_0/1 are reset to their initial values before
evaluation.
The brightest and lowest pixel value inside the active area
is available in ref_pixel_red_0/1, ref_pixel_green_0/1 and
ref_pixel_blue_0/1. The evaluated values for the lowest
colour value pixel cannot be lower than the lowest
threshold value.
2004 Apr 05
In the enhanced mode all input data is used for
measurement (see Fig.15)
In the non-enhanced mode only one input line, defined
by ref_row_1 and one input column, defined by
ref_col_1, is used (see Fig.16).
XGA analog input flat panel controller
53
handbook, halfpage
handbook, halfpage
Active area: shaded.
Active area: shaded.
start
start
eval_col_0
eval_col_0
ref_colour_0
Fig.16 Non-enhanced mode.
ref_colour_0
Fig.15 Enhanced mode.
ref_colour_0
ref_col_1
ref_colour_1
ref_colour_1
ref_colour_0
ref_colour_1
ref_colour_1
eval_col_1
eval_col_1
SAA6713AH
Product specification
eval_row_0
eval_row_1
eval_row_0
ref_row_1
eval_row_1
MHC222
MHC223