26 LCD CONTROLLER (LCDC)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
26-31
Writing Display Data
26.6.3
The LCD controller may generate an interrupt at the beginning with the vertical non-display period after finishing
each frame refresh sequence. Furthermore, VNDPF/LCDC_PSAVE register is provided and is set to 1 if the display
is in a vertical non-display period.
To eliminate screen flicker, display data, LUT data and the display buffer should be changed in a vertical non-
display period by using this interrupt or VNDPF.
For more information on the LCDC interrupt, see Section 26.7, “LCDC Interrupt.”
Inverting and Blanking the Display
26.6.4
The display can be blanked (the entire screen turned black or white) without rewriting the contents of the VRAM.
Setting BLANK/LCDC_DISPMOD register to 1 causes the FPDAT signal to go low or high, blanking the display.
Setting it to 0 turns the display back on. Whether the screen turns black or white is determined by SWINV/LCDC_
DISPMOD register described below.
The display can be inverted simply by manipulating a control bit. Setting SWINV to 1 inverts the display, and set-
ting it to 0 returns the display to normal. This is accomplished by inverting the display data output from the LCDC,
rather than by inverting the pixel data in the display memory.
The screen can be made to blink using these operations. Make sure switching takes place within the vertical non-
display period (VNDPF = 1).
Picture-in-Picture Plus and Sub-Window
26.6.5
Picture-in-Picture Plus enables a sub-window to be overlaid on the main window. The sub-window may be posi-
tioned anywhere within the main window and is controlled through the sub-window control registers. The sub-
window retains the same color depth as the main window. The sub-window also supports the virtual screen feature
the same as the main window.
The following diagram shows the sub-window configuration parameters.
Main window
Sub-window
B
C
D
E
A
A: Panel's origin = Main window start address
B: Sub-window x start position
C: Sub-window y start position
D: Sub-window x end position
E: Sub-window y end position
6.5.1 Sub-window Configuration Parameters
Figure 26.
Display memory for the sub-window
The display data for the sub-window can be stored in IVRAM or the external VRAM. If the same memory as
the main window is used, make sure that the display data areas for the main window and sub-window do not
overlap.
The sub-window start address is specified by the LCDC_SUBADR register in the same manner as the main
window. The start address set in the LCDC_SUBADR register corresponds to the upper left corner of the sub-
window.
Note that a word boundary address (A[1:0] = 0b00) in IVRAM or the external VRAM must be specified to this
register.
The sub-window width must be a multiple of (32 bits
÷
bpp).
Sub-window coordinates
The display position and size of the sub-window are configured with the X and Y coordinates of the start posi-
tion (upper left corner) and end position (lower right corner).