S1D13505 Epson Electronics America, Inc., S1D13505 Datasheet - Page 188

• Manufacturer Part Number: S1D13505
• Description: LCD Controller
• Manufacturer: Epson Electronics America, Inc.

Page 34
S1D13505
X23A-G-003-07
The following pans to the right by one pixel in 4 bpp display mode.
1. This is a pan to the right. Increment pan_value.
2. Mask off the values from pan_value for the pixel panning and start address register
3. Write the pixel panning and start address values to their respective registers using the
Example 4: Scrolling - Up and Down
To scroll down, increase the value in the Screen 1 Display Start Address Register by the
number of words in one virtual scan line. To scroll up, decrease the value in the Screen 1
Display Start Address Register by the number of words in one virtual scan line.
Example 5: Scroll down one line for a 16 color 640x480 virtual image using a
1. To scroll down we need to know how many words each line takes up. At 16 colors (4
2. Increment the start address by the number of words per virtual line.
3. Separate the start address value into three bytes. Write the LSB to register [10h] and
pan_value = pan_value + 1
portions. In this case, 4 bpp, the lower two bits are the pixel panning value and the up-
per bits are the start address.
pixel_pan = pan_value AND 3
start_address = pan_value SHR 3
(the fist two bits of the shift account for the pixel_pan the last bit of the shift converts
the start_address value from bytes to words)
procedure outlined in the registers section.
bpp) each byte contains two pixels so each word contains 4 pixels.
offset_words = pixels_per_line / pixels_per_word = 640 / 4 = 160 = A0h
We now know how much to add to the start address to scroll down one line.
start_address = start_address + words
the MSB to register [12h].
320x240 single panel LCD.
Epson Research and Development
Programming Notes and Examples
Vancouver Design Center
Issue Date: 01/02/05