VII LCD CONTROLLER BLOCK: LCD CONTROLLER
The starting position of the view port is changed by modifying the screen 1 start address register described above. For example, when the start address is incremented by 16 bits, the pixel displayed at the 17th dot on line 1 moves to the beginning of the line, and the 16 leading pixels move off the screen. This is the basic operation for panning an image. However, when this operation is performed, the 16 leading pixels on line 2 are normally displayed at the end of line 1, resulting in dislocation of the image. To prevent this problem, set an address offset between the last piece of pixel data on a line and the first piece of pixel data on the next line.
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| Virtual screen |
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| Offset |
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| View port |
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| C |
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| View port |
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| Horizontal |
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| Horizontal |
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B + C = A (HW)
Figure 2.18 Offsets Comprising a Virtual Screen
Set the offset value in the MADOFS[7:0] (D[7:0])/memory address offset register (0x39FFF1) as a halfword address. Be aware that if this address is calculated from the number of pixels, the offset value may change depending on the display mode. When configuring a
This setting allows the view port to be moved horizontally (panned) by an amount equal to the offset, by changing the screen 1 start address register. The values set in the screen 1 start address register are halfword addresses. Therefore, the view port is moved in
Movement of the virtual screen in the vertical direction is determined by the installed memory capacity, which is limited to a maximum of 256K bytes of display memory. To scroll the view port down by one line, set a
Even when a virtual screen is used, the
Screen 1 start
Virtual screen in the display memory
LCD panel
address
Screen 1 view port
Image 1
Screen 1
Screen 2
S1VSIZE
+ 1 (lines) LDVSIZE + 1 (lines)
Screen 2 start
address
Screen 2 view port
Image 2
(LDHSIZE+1) ⋅ 16 / BPP |
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(HW) |
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BPP = 1, 2, 4, or 8 (bpp)
(LDHSIZE + 1) ⋅ 16 (pixels)
Figure 2.19 Virtual Screen and
Note: In portrait mode (described later), the memory address offset register (0x39FFF1) has no effect.
EPSON | S1C33L03 FUNCTION PART |