ssd1908 Solomon Systech Limited:, ssd1908 Datasheet - Page 142

• Manufacturer Part Number: ssd1908
• Description: Lcd Drivers,lcd Controllers
• Manufacturer: Solomon Systech Limited:

19.2 180° Display Rotate Mode
19.2.1 Register Programming
Solomon Systech
Figure 19-2 : Relationship Between The Screen Image and the Image Refreshed in 180 ° ° ° ° Display Rotate
Line Address Offset
The following figure shows how the programmer sees a 480x320 landscape image and how the image is
being displayed. The application image is written to the SSD1908 in the following sense: A–B–C–D. The
display is refreshed by the SSD1908 in the following sense: D-C-B-A.
Enable 180 ° ° ° ° Display Rotate Mode
Display Start Address
physical memory
start address
The Main Window Line Address Offset register (REG[78h], REG[79h]) is based on the display
width and programmed using the following formula.
Set Display Rotate Mode Select bits to 10 (REG[71h] bits 1:0 = 10).
The display refresh circuitry starts at pixel “D”, therefore the Main Window Display Start Address
registers (REG[74h], REG[75h], REG[76h]) must be programmed with the address of pixel “D”.
To calculate the value of the address of pixel “D” use the following formula (assumes 8bpp color
depth).
Main Window Line Address Offset bits 9-0
= Display width in pixels ÷ (32 ÷ bpp)
= 320 pixels ÷ (32 ÷ 8 bpp)
= 80 (50h)
Main Window Display Start Address bits 16-0
= ((Image address + (image width x (panel height – 1) + panel width) x bpp ÷ 8) ÷ 4) –1
= ((0 + (480 pixels x 319 pixels + 480 pixels) x 8 bpp ÷ 8) ÷ 4) – 1
= 38399 (95FFh)
A
C
image seen by programmer
= image in display buffer
Window
Display
Rotate
480
B
D
display start address
Mode.
(panel origin)
Oct 2003
D
B
image refreshed by SSD1908
P 132/132 Rev 1.0
Window
Display
Rotate
480
C
A
SSD1908