TVP3020 datasheet(40/98 Pages) TI

40 / 98 page

2–26

The crosshair cursor and the auxiliary window function utilize the same set of window registers. Therefore,

care must be taken if the crosshair cursor is to be displayed when the auxiliary window function is enabled

(ACR0 = 1). See Section 2.6.

2.5.5

Dual-Cursor Positioning

Both the user-definable 64

× 64 cursor and the crosshair cursor may be enabled for display simultaneously,

allowing the generation of custom crosshair cursors. As previously mentioned, the sprite-origin (x,y) register

specifies the 64

× 64 cursor pattern location relative to the cursor position and crosshair cursor.

Figure 2–8 illustrates displaying the dual cursors, showing the relationship between the auxiliary window,

the crosshair cursor, and the 64

× 64 cursor for the case where the sprite-origin (x,y) register is set to

(31, 31).

Window Start (X, Y)

Cursor Position (X, Y)

Crosshair Cursor

64 X 64 Cursor Area

Window Stop (x, y)

Crosshair Window

Figure 2–8. Dual-Cursor Positioning

Figure 2–9 shows one possible custom cursor that could be created by setting the sprite-origin register to

(0,0) and drawing an arrow in 64

× 64 cursor RAM. The cursor window has been set to full screen by setting

the window-start (x,y) register to 0000 (hex) and the window-stop registers to the last active pixel location.

The 64

× 64 cursor area could be located in different locations about the cursor position by programming

the sprite-origin (x,y) registers to different values as described earlier (see Section 2.5.3).

Cursor Position (x, y)

Crosshair Cursor

× 64 Cursor Area

Sprite Origin = (0, 0)

Crosshair Window = Full Screen

Figure 2–9. One Possible Custom Cursor Creation

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