sed1355 ETC-unknow, sed1355 Datasheet - Page 195

• Manufacturer Part Number: sed1355
• Description: Sed1355 Embedded Ramdac Lcd/crt Controller
• Manufacturer: ETC-unknow

Epson Research and Development
Vancouver Design Center
8.5 Examples
Programming Notes and Examples
Issue Date: 99/04/27
Example 7: Enable portrait mode for a 640x480 display at 8 bpp.
Before switching to portrait mode, display memory should be cleared to make the transition
smoother. Currently displayed images can not be simply rotated by hardware.
1.
2.
3.
4.
Example 8: Pan the above portrait mode image to the right by 3 pixels then scroll it up by 4
Pan the above portrait mode image to the right by 3 pixels then scroll it up by 4 pixels.
1.
2.
3.
The first step toward enabling portrait mode is to set the line offset to 1024 pixels. The Line
Offset register is the offset in words.
Write 200h to registers [17h]:[16h]. That is write 02h to register [17h] and 00h to register
[16h].
The second step to enabling portrait mode is to set the Display 1 Start Address. The Display
Start Address registers form a pointer to a word, therefore the value to set the start.
Write C0h (192 or (1024 - 480)/2) to registers [10h], [11h] and [12h]. That is write Ch) to reg-
ister [10h], 00h to register [11h] and 00h to register [12h].
Enable display rotation by setting bit 7 of register [0Dh].
The display is now configured for portrait mode use. Offset zero into display memory will
correspond to the upper left corner of the display. The only difference seen by the programmer
will be in acknowledging that the display offset is now 1024 pixels regardless of the physical
dimensions of the display surface.
With portrait mode enabled, the x and y control is rotated as well. Simply swap the x and y
co-ordinates and calculate as if the display were not rotated.
Calculate the new start address and pixel pan values.
BytesPerScanline = 1024
PixelPan = newX & 01h;
StartAddr = (newY * BytesPerScanline / 2) + (newX & FFFEh) >> 1;
Write the start address during the display enabled portion of the frame.
a) loop waiting for vertical non-display (b7 of register [0Ah] high).
b) Loop waiting for the end of vertical non-display.
c) Write the new start address.
do register = ReadRegister(0Ah)
do register = ReadRegister(0Ah)
SetRegister(REG_SCRN1_DISP_START_ADDR0, (BYTE) (dwAddr & FFh));
SetRegister(REG_SCRN1_DISP_START_ADDR1, (BYTE)((dwAddr >> 8) & FFh));
while (80h != (register & 80h));
while (80h == (register & 80h));
pixels.
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SED1355
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