sed1355 ETC-unknow, sed1355 Datasheet - Page 193

• Manufacturer Part Number: sed1355
• Description: Sed1355 Embedded Ramdac Lcd/crt Controller
• Manufacturer: ETC-unknow

Epson Research and Development
Vancouver Design Center
8 Hardware Rotation
8.1 Introduction To Hardware Rotation
8.2 SED1355 Hardware Rotation
8.3 Registers
Programming Notes and Examples
Issue Date: 99/04/27
REG[0Dh] Display Mode Register
Portrait Mode
Hardware
Enable
Simultaneous
Option Select
Display
Bit 1
Most computer displays operate in landscape mode. In landscape mode the display is wider than it
is high. For instance, a standard display size is 640x480 where the width is 640 pixels and the height
is 480 pixels.
Portrait mode rotates the display image clockwise ninety degrees, resulting in a display that is taller
than it is wide. Placing the 640x480 display in portrait mode will yield a display that is now 480
pixels wide and 640 pixels high.
The SED1355 provides hardware support for portrait mode output in 16 and 8 bpp modes.
The switch to portrait mode carries several conditions:
• The (virtual) display offset must be set to 1024 pixels.
• The display start address is calculated differently in portrait mode.
• Calculations that would result in panning in portrait mode result in scrolling in portrait mode and
This section will detail each of the registers used to setup portrait mode operations on the SED1355.
The functionality of most of these registers has been covered in previous sections but is included
here to make this section complete.
The first step toward setting up portrait mode operation is to set the Hardware Portrait Mode Enable
bit to 1 (bit 7 of register [0Dh]).
vice-versa.
Simultaneous
Option Select
Display
Bit 0
Bit-Per-Pixel
Select Bit 2
Bit-Per-Pixel
Select Bit 1
Bit-Per-Pixel
Select Bit 0
CRT Enable
X23A-G-003-05
LCD Enable
SED1355
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