SED1374 Datasheet, PDF (128/420 Pages) Epson Company – SED1374 Embedded Memory Color LCD Controller

Page 32
Epson Research and Development
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REG[0Fh] Screen 2 Display Start Address 0 (LSB)
Start Addr Bit Start Addr Bit Start Addr Bit Start Addr Bit Start Addr Bit Start Addr Bit Start Addr Bit Start Addr Bit
7
6
5
4
3
2
1
0
REG[10h] Screen 2 Display Start Address 0 (LSB)
reserved
Start Addr Bit Start Addr Bit Start Addr Bit Start Addr Bit Start Addr Bit Start Addr Bit Start Addr Bit
14
13
12
11
10
9
8
Figure 5-6: Screen 2 Start Address Registers
In landscape mode these two registers form the offset to the word in display memory to be
displayed immediately after the screen 1 area of display memory. Changing these registers
by one will shift the display 2 to 16 pixels, depending on the current color depth.
Split screen operation is not supported in SwivelView mode, leaving this register un-used.
Refer to Table 5-1:, “Number of Pixels Panned Using Start Address,” on page 28 to see the
minimum number of pixels affected by a change of one to these registers
5.3.2 Examples
Example 5: Display 200 scanlines of image 1 and 40 scanlines of image 2. Image 2 is
located first (offset 0) in the display buffer followed immediately by im-
age 1. Assume a 320x240 display and a color depth of 4 bpp.
1. Calculate the Screen 1Vertical Size register values.
vertical_size = 200 = C8h
Write the Vertical Size LSB, REG[13h], with C8h and Vertical Size MSB, REG[14h],
with a 00h.
2. Calculate the Screen 1 Start Word Address register values.
Screen 2 is located first in display memory, therefore we must calculate the number of
bytes taken up by the screen 2 data.
bytes_per_line = pixels_per_line / pixels_per_byte = 320 / 2 = 160
total bytes = bytes_per_line x lines = 160 x 40 = 6400.
Screen 2 requires 6400 bytes (0 to 6399) therefore the start address offset for screen 1
must be 6400 bytes. (6400 bytes = 3200 words = C80h words)
Set the Screen 1 Start Word Address MSB, REG[0Dh], to 0Ch and the Screen 1 Start
Word Address LSB, REG[0Ch], to 80h.
SED1374
X26A-G-002-02
Programming Notes and Examples
Issue Date: 99/04/27