SAA6721E Datasheet, PDF (53/72 Pages) NXP Semiconductors – SXGA RGB to TFT graphics engine

Philips Semiconductors
SXGA RGB to TFT graphics engine
Preliminary specification
SAA6721E
8.6.3 UPSCALER TRANSITION FUNCTION
A special feature of the zooming algorithm is a free
programmable transition function which allows smoothing
or sharpening of the transition between pixels that have
been calculated.
This function will be stored in a look-up table, containing
64 words of 7 bits; thus a function of 64 points with a
resolution from 0 to 64 can be programmed.
Programming is performed using the registers coeff_index
and coeff_value. The first register defines the point of the
function, the second the value. Writing to register
coeff_value increments the value of coeff_index
automatically, so that the next point of the function is
addressed. Additionally no register increment will be
performed, so that subsequent I²C-bus write addresses
always have the same register coeff_value.
8.7 Panning unit
If the scaled or non-scaled input frame does not fit into the
needed output frame, whether it is to large or to small, the
panning unit enlarges the input frame to the size of the
output frame. This is achieved by generating a border
region around the input frame, or it cuts the input frame
down to the size of the output frame. The position of the
top left pixel of the input frame inside the output frame
must be defined with pic_v_offset and pic_h_offset.
The output frame size must be programmed with
out_v_size and out_h_size (see Fig.17).
If the input frame is to large only the right and bottom part
will be cropped. The colour of the generated border region
must be set via border_colour_red, border_colour_green,
and border_colour_blue.
handbook, full pagewidth
INPUT FRAME
pic_v_offset
pic_h_offset
pic_v_offset
pic_h_offset
OUTPUT FRAME
out_h_size
Fig.17 Picture positioning.
out_v_size
MHB257
1999 May 11
53