SED1374 Datasheet, PDF (124/420 Pages) Epson Company – SED1374 Embedded Memory Color LCD Controller

Page 28
Epson Research and Development
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5.2.1 Registers
REG[0Ch] Screen 1 Display Start Address 0 (LSB)
Start Addr Start Addr Start Addr Start Addr
Bit 7
Bit 6
Bit 5
Bit 4
Start Addr
Bit 3
Start Addr
Bit 2
Start Addr
Bit 1
Start Addr
Bit 0
REG[0Dh] Screen 1 Display Start Address 1 (MSB)
reserved
Start Addr Start Addr Start Addr
Bit 14
Bit 13
Bit 12
Start Addr
Bit 11
Start Addr
Bit 10
Start Addr
Bit 9
Start Addr
Bit 8
Figure 5-3: Screen 1 Start Address Registers
In landscape mode these two registers form the offset to the word in display memory to be
displayed in the upper left corner of the screen. Screen 1 is always the top of a display
frame, starting in the upper left corner and descending downward. Changing these registers
by one will shift the display 2 to 16 pixels, depending on the current color depth.
In SwivelView mode these registers form the offset to the byte in display memory from
where screen 1 will start displaying. Changing these registers in SwivelView mode will
result in a shift of 1 to 8 pixels depending on the color depth.
Refer to Table 5-1: “Number of Pixels Panned Using Start Address” to see the minimum
number of pixels affected by a change of one to these registers
Table 5-1: Number of Pixels Panned Using Start Address
Color Depth (bpp) Pixels per Word
1
16
2
8
4
4
8
2
Landscape Mode
Number of Pixels Panned
16
8
4
2
SwivelView Mode
Number of Pixels Panned
8
4
2
1
5.2.2 Examples
For the following examples assume the display system has been set up to view a 320x240
4 bpp image in a 256x64 viewport. Refer to Section 2, “Initialization” on page 8 and
Section 5.1, “Virtual Display” on page 25 for assistance with these settings. The examples
are shown in a C-like syntax.
Example 3: Panning (Right and Left)
To pan to the right increase the start address value by one. To pan to the left decrease the
start address value. Keep in mind that, with the exception of 8 bit-per-pixel SwivelView
mode, the display will jump by more than one pixel as a result of changing the start address
registers.
SED1374
X26A-G-002-02
Programming Notes and Examples
Issue Date: 99/04/27