Page 28
Epson Research and Development
Vancouver Design Center
S1D13704
Programming Notes and Examples
X26A-G-002-03
Issue Date: 01/02/12
5.2.1 Registers
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
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.
REG[0Ch] Screen 1 Display Start Address 0 (LSB)
Start Addr
Bit 7
Start Addr
Bit 6
Start Addr
Bit 5
Start Addr
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
Bit 14
Start Addr
Bit 13
Start Addr
Bit 12
Start Addr
Bit 11
Start Addr
Bit 10
Start Addr
Bit 9
Start Addr
Bit 8
Table 5-1: Number of Pixels Panned Using Start Address
Color Depth (bpp)
Pixels per Word
Landscape Mode
Number of Pixels Panned
SwivelView Mode
Number of Pixels Panned
1
16
16
8
2
8
8
4
4
4
4
2
8
2
2
1
*