VII LCD CONTROLLER BLOCK: LCD CONTROLLER

A-1

Split-Screen Display

The LCD controller supports a split-screen function, allowing different images to be displayed on two vertically split screens on the LCD panel. To discriminate between these two screens, the upper half of the LCD panel is referred to as "screen 1" and the lower half is referred to as "screen 2".

 

 

 

Display memory

 

LCD panel

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Screen 2 data

 

Screen 1

 

 

S1VSIZE

Screen 2 start address

 

 

 

 

 

 

 

 

 

 

+ 1 (lines) LDVSIZE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+ 1 (lines)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Screen 1 data

Screen 2

Screen 1 start address (LDHSIZE + 1) 16 (pixels)

Figure 2.16 Split-Screen Display

A register similar to the screen 1 start address register described above is provided; it is called the "screen 2 start address register (0x39FFEE, 0x39FFEF)". Use this register to set the start address of screen 2. In the initial state, the start address of screen 2 is set to 0x0, as with screen 1.

Use the number of lines on screen 1 to specify the position at which to divide between the two screens. To evenly split an LCD panel with 240 lines of vertical resolution into upper and lower halves, for example, set the value 119 in S1VSIZE[9:0] (D[9:0])/screen 1 vertical size register (0x39FFF3, 0x39FFF2). The LCD panel is separated into screen 1 consisting of lines 0–119, and screen 2 consisting of lines 120–239.

In the initial state, S1VSIZE[9:0] is set to 0. As a result, screen 1 is nonexistent and screen 2 is displayed over the entire panel.

To display only screen 1, set the same value in S1VSIZE[9:0] as that set in the LDVSIZE[9:0] (D[9:0])/vertical panel size register (0x39FFE6, 0x39FFE5). The entire screen can be changed instantaneously to different images by switching between S1VSIZE = LDVSIZE and S1VSIZE = 0.

Virtual Screen and View Port

The LCD controller has a virtual-screen function that allows any necessary portion of the screen to be displayed through panning or scrolling, by holding in memory than that required to achieve the resolution. However, because a virtual screen is configured within the display memory, it is limited in size to a maximum of 256K bytes. The area corresponding to the actual LCD panel size is referred to as a view port, and can be relocated within the virtual screen by changing the display start address.

Virtual screen

View port

(LCD panel size)

Figure 2.17 Virtual Screen and View Port

The procedure for setting a virtual screen and panning or scrolling the view port is explained below, assuming that screen 1 is used.

Because the view port than that required to achieve the resolution size is equal to that required to achieve the resolution of the LCD panel, the values set in the horizontal panel size register (0x39FFE4) and vertical panel size register (0x39FFE6, 0x39FFE5) are applied directly as they are.

B-VII

LCDC

S1C33L03 FUNCTION PART

EPSON

B-VII-2-23