TM1100 Preliminary Data Book
Philips Semiconductors
13-28
PRELIMINARY INFORMATION
File: icp.fm5, modified 7/26/99
3 = RGB 24 packed
4 = RGB 8A (RGB 233)
5 = RGB 8R (RGB 332)
6 = RGB15+
α
7 = RGB 16
The 422SEQ bit controls the internal sequencing of the
YUV to RGB operation. It is set to one when YUV 4:2:2
output is selected. When 422SEQ is zero, normal RGB
output is assumed. In this mode, the input is YUV 4:2:2
or YUV 4:2:0, and the output is RGB. To generate the
RGB output, the YUV 4:2:2 or YUV 4:2:0 input must be
upscaled to YUV 4:4:4 before conversion to RGB. This
means the scaling factor for U and V must be twice the
scaling factor for Y. The internal sequencing of the filter
in this case is UVY, UVY, UVY to generate RGB, RGB,
RGB. For YUV 4:2:2 output formats, no upscaling of U
and V is required. In this case, the 422SEQ bit is set to
one, and the filter sequence is UVYY, UVYY, UVYY.
The 422SEQ bit can be set in RGB output mode to de-
crease the processing time for the image at the expense
of color bandwidth and some corresponding decrease in
picture quality. If the 422SEQ bit is set for RGB output,
the filter will perform the UVYY sequence. In this case,
the U and V components are not upscaled by 2, and the
YUV to RGB converter updates its U and V components
every other pixel. In the normal case (422SEQ=0), it
takes 6 clocks to generate two RGB pixels. In the
422SEQ=1 case, it takes 4 clocks to generate two RGB
pixels, reducing processing time by 33%.
The YUV420 bit indicates that the input data is in YUV
4:2:0 format. In YUV 4:2:0 format, the U and V compo-
nents are half the width and half the height of the Y data.
YUV 4:2:0 data is normally converted to YUV 4:2:2 data
by a separate vertical upscaling by a factor of 2.0 for best
quality. The YUV420 bit allows using YUV 4:2:0 data di-
rectly but with some quality degradation. When YUV420
is set, the ICP up scales the data vertically by line dupli-
cation. Each U and V input line is used twice. The sepa-
rate vertical scaling step is eliminated at the expense of
some quality since the lines are simply duplicated rather
than being fully scaled and filtered.
The OEN bit enables overlay. You set it to one if an over-
lay is used, zero if not. Overlays are only valid for PCI
output.
The PCI bit selects PCI as the output port for the ICP da-
ta. A one selects PCI output; a zero selects SDRAM out-
put.
The BEN bit enables bit masking. You set it to one if bit
masking is used, zero if not. Bit masking is only valid for
PCI output.
The GETB bit is an optional bit for large (> 4) down scal-
ing. When GETB is zero (normal operation), the 5-tap fil-
ter receives the pixel nearest the output pixel as its cen-
ter pixel plus the two adjacent input pixels on either side
of this pixel to form the five filter inputs. When GETB is
set, the filter receives the pixel nearest the output pixel
as its center pixel plus the two adjacent output pixels on
either side of this pixel to form the five filter inputs. The
effective algorithm is pixel picking plus 5-tap filtering of
the result. GETB also forces the scaling LSB value to ze-
ro, since output pixels are being filtered and no interpo-
lation is used.
The OFRM bit field selects the overlay data format, as
shown in the Control word format list.
The CHK bit enables chroma keying. You set it to one if
chroma keying is used, zero if not.
The OLLE bit sets the endian-ness of the overlay data in-
put. You set it to one if the overlay data is little-endian,
zero if big endian. The OLLE bit is normally set to the
same value as the LE bit in the Status register.
The LE bit sets the endian-ness of the RGB/YUV output
data. You set it to one if the output data is little-endian,
zero if big endian. The LE bit is normally set to the same
value as the LE bit in the Status register.
The RGB field defines the output data format, as shown
in the Control word format list.
Important Note: You must set the ICP DMA Enable bit
(IE) in the BIU_CTL register of the PCI interface for RGB
output to PCI. This bit must be set before initiating RGB
to PCI operations, or the ICP will stall waiting for the PCI
to become ready.