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Epson Research and Development
Vancouver Design Center
StartAddress
= PanValue SHR 2 (remove PixelPan bits)
3. Write the pixel panning and start address register values using the procedure outlined
in Section 5.2.1, “Registers” on page 31.
Example 4:Scrolling - Up and Down
To scroll down, increase the value in the Display Start Address Registers (REG[042h],
REG[043h], REG[044h] for LCD, REG[062h], REG[063h], REG[064h] for CRT/TV) by
the number of words in one virtual scan line. To scroll up, decrease the value in the Display
Start Address Registers by the number of words in one virtual scan line.
The following example scrolls down one line for a 16 color (4 bpp) 800x600 virtual image
using a 640x480 single panel LCD.
1. Determine the number of words in each line of the virtual image. For a color depth of
4 bpp each byte contains two pixels so each word contains 4 pixels.
OffsetWords
= PixelsPerVirtualLine ÷ PixelsPerWord
= 800 ÷ 4
= 200
= C8h
2. Increment the display start address by the number of words per virtual line.
StartAddress
= StartAddress + OffsetWords
= StartAddress + C8h
3. Separate the display start address value into three bytes. For the LCD, write the LSB
to REG[042h] and the MSB to REG[044h]. For the CRT/TV, write the LSB to
REG[062h] and the MSB to REG[064h].
For the LCD, REG[044h] is set to 00h, REG[043h] is set to 00h, and REG[042h] is set
to C8h.
For the CRT/TV, REG[064h] is set to 00h, REG[063h] is set to 00h, and REG[062h]
is set to C8h.
Note
The above example assumes the display start address was initially 0 (the beginning of
the display buffer).
S1D13506
X25B-G-003-03
Programming Notes and Examples
Issue Date: 01/02/06
EPSON [ EPSON COMPANY ]
