Advanced Techniques; Virtual Displays; Registers - Epson SED1352 Technical Manual

Page 28

5 ADVANCED TECHNIQUES

This section presents information on the following:
•

virtual displays

• bitmaps and text displays
• reading and writing to the SED1352 registers
• split screen displays
• panning and scrolling.
• power saving.
5.1 Virtual Displays
This section presents a detailed description of the Address Pitch Adjustment Register, followed by a description of a virtual
display. Afterwards an example is given, showing how to create a virtual display.

5.1.1 Registers

Note
Register bits discussed in this section are highlighted.
AUX[0D] Address Pitch Adjustment Register
I/O address = 1101b, Read/Write.
Addr Pitch Addr Pitch
Adjustment Adjustment
Bit 7 Bit 6
bits 7-0 Addr Pitch Adjustment Bits [7:0]
These bits set the numerical difference between the last address of a display line, and the first address in
the following line.
If the Address Pitch Adjustment is not equal to zero, then a virtual screen is formed. The size of the virtual
screen is only limited by the available display memory. The actual display output is a window that is part
of the whole image stored in the display memory. For example, with 128K of display memory, a 640x400
16-gray image can be stored. If the output display size is 320x240, then the whole image can be seen by
changing display starting addresses through AUX[06] and [07], and AUX[08] and [09]. Note that a virtual
screen can be produced on either a single or dual panel.
In 8-bit memory interface, if the Address Pitch Adjustment is not equal to zero, then a virtual screen with a
line length of (Line Byte Count +AUX[0D]) bytes is created, with the display reflecting the contents of a
window (Line Byte Count+1) bytes wide. The position of the window on the virtual screen is determined
by AUX[06] and [07], and AUX[08] and [09].
In 16-bit memory interface, if the Address Pitch Adjustment is not equal to zero, then a virtual screen with
a line length of 2*(Line Byte Count +AUX[0D]) bytes is created, with the display reflecting the contents
of a window 2*(Line Byte Count+1) bytes wide. The position of the window on the virtual screen is deter-
mined by AUX[06] and [07], and AUX[08] and [09].
SED1352
X16-BG-007-04
Addr Pitch Addr Pitch
Adjustment Adjustment
Bit 5 Bit 4
Epson Research and Development
Addr Pitch Addr Pitch
Adjustment Adjustment
Bit 3 Bit 2
Vancouver Design Center
Addr Pitch Addr Pitch
Adjustment Adjustment
Bit 1 Bit 0
Programming Notes and Examples
Issue Date: 98/10/08