PNX1302EH NXP Semiconductors, PNX1302EH Datasheet - Page 235

• Manufacturer Part Number: PNX1302EH
• Manufacturer: NXP Semiconductors

Specifications of PNX1302EH

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Philips Semiconductors
The input and output addresses are the byte addresses
of their respective tables. The input and the output ad-
dress need to be 64-byte aligned.
The input and output line offsets define the difference in
bytes from the address of the first pixel in the first line to
the address of the first pixel in the second line for their re-
spective blocks. The line offset must be constant for all
lines in each table. It allows some space between the
end of one line and the start of the next line. It also allows
the ICP to scale and filter a subset of an existing image,
such as magnifying a portion of an image. Offset values
are 16-bit, two’s complement integer values.
Vertical filtering has a restriction on input and output line
offset values: they must be positive, and they must be
multiples of 64. Note that this only applies to the line-to-
line spacing. Even with this restriction, input images may
be any height and any width and may start at any byte
address. Also, image subsets of arbitrary height and
width can be used. As long as the original image has a
line offset which is a multiple of 64, all subsets of that im-
age will also automatically have a line offset, which is a
multiple of 64 - the same as the original image. All imag-
es should have line offsets which are multiples of 64 as
good programming practice, even though this restriction
only applies to vertical filtering. If an image does not have
a multiple of 64 line offset, it can be converted to that by
using horizontal filtering in the image block move mode
with the output offset value being a multiple of 64.
The input and output image height and width values are
the height in lines and width in pixels per line for their re-
spective images. The height and width are 16-bit positive
binary numbers between 0 and 64K-1.
The Integer increment and Fraction increment values are
the scaling parameters. The Integer value is a 16-bit in-
teger, and the Fraction value is a positive binary fraction
between 0 and 0.99999+. For up scaling (output image
bigger), the increment value is the inverse of the scaling
value. If you are upscaling by a factor of 2.5, the incre-
ment value will be the inverse of 2.50 = 0.40. The Integer
increment value will be 0 and the Fraction increment val-
ue will be 0.40. For down scaling, the increment value is
equal to the scaling value. If you are down scaling by 2.5
(output image smaller), the Integer increment value will
be 2, and the Fraction increment value will be 0.500.
To perform scaling, the Integer and Fractional increment
values must be generated and placed in the parameter
table. The simplest way to generate these values in com-
mon computer languages such as C is as follows:
1. Generate the Increment Value as a floating point
2. Multiply the Increment Value by 65536
3. Convert the result to a Long Integer (32 bits). The up-
4. Store the 32-bit Long integer in the parameter table as
number = Input Height / Output Height
per 16 bits of the Long integer will be the Integer in-
crement value, and the lower 16 bits will be the Frac-
tional value.
the combined Integer and Fractional increment val-
ues.
The Start Fraction defines the starting value in the scal-
ing counter for each line. It is a 16-bit, two’s complement
fractional value between -0.500 and 0.49999+. This val-
ue is placed in the Start Fraction allows the input data to
be offset by up to half a line, referred to the input pixel
grid. It is set to ‘0’ for all conventional YUV input data.
14.6.10.3 Control word format
The Control word provides bit fields which affect the ver-
tical filtering operation. The format of the Control word is
as follows.
Bit
15
The Bypass bit causes the data to bypass the 5-tap filter.
The scaling operation selects the center line, and this
line is passed to the filter output. No filtering or interpola-
tion is provided. If the scaling factor is 1.0, the result is an
image block move where the image is moved from one
part of SDRAM to another without modification. If the
scaling factor is other than 1.0, the effective algorithm is
line picking, where the input line nearest the output line
location is used as the output line.
14.6.11 Horizontal Filter with RGB/YUV
This routine moves an N x M image in YUV 4:2:2, YUV
4:2:0 or YUV 4:1:1 format from SDRAM to the PCI bus or
to SDRAM. The image is scaled and filtered in the hori-
zontal direction during the move. Optional bit masking
and/or RGB overlay can be used during the move when
PCI output is specified.
14.6.11.1 Algorithms
The routine reads image data from SDRAM using the Y,
U, and V address counters, scales and filters the data in
the horizontal direction and writes it to the PCI interface
or SDRAM. The 5-tap filter scales and filters the data.
The LSB Increment value for each of the Y, U and V com-
ponents supplied by the parameter table determines the
scaling. Separate scaling factors allows YUV 4:2:2 inter-
spersed to co-sited transformation as the data is being
filtered. The scaled and filtered data is converted to RGB
or YUV format before being sent to the PCI interface or
to SDRAM. In the PCI output case, overlay data with al-
pha blending and chroma keying can be added to the
output image, and the output image can be gated by a bit
mask before it is sent to the PCI interface.
The routine reads and writes a line at a time until the full
image is transferred. The filter mirrors the ends of each
line to provide the extra pixels needed by the filter at the
ends of each line.
PRELIMINARY SPECIFICATION
Name
Bypass
Conversion to PCI or SDRAM
Function
Bypass filter. Picks nearest input line
and passes it to output unfiltered.
When Bypass is set & scale factor is
1.0, this results in an image block
move
Image Coprocessor
14-25