Philips S1D13505 用户手册

Page 135

Vancouver Design Center

Hardware Functional Specification

S1D13505

Issue Date: 01/02/02 

X23A-A-001-14

Computer displays are refreshed in landscape – from left to right and top to bottom; computer images 
are stored in the same manner. When a display is used in SwivelView it becomes necessary to rotate 
the display buffer image by 90

°

. SwivelView rotates the image 90

°

 clockwise as it is written to the 

display buffer. This rotation is done in hardware and is transparent to the programmer for all display 
buffer reads and writes. 

SwivelView uses a 1024 

× 

1024 pixel virtual image. The following figures show how the 

programmer sees the image and how the image is actually stored in the display buffer. The display 
is refreshed in the following sense: C–A–D–B. The application image is written to the S1D13505 in 
the following sense: A–B–C–D. The S1D13505 rotates and stores the application image in the 
following sense: C–A–D–B, the same sense as display refresh.

The image must be written with a 1024 pixel offset between adjacent lines (e.g. 1024 bytes for
8 bpp mode or 2048 bytes for 16 bpp mode) and a display start address that is non-zero.

1024 pixels

10

24

 pi

xel

s

image seen by programmer

image in display buffer

1024 pixels

portrait

window

W

H

A

B

C

D

AB

C

D

H

W

start

address

po
rt

rai
t

w

ind
ow

display