B69000 Asiliant Technologies, B69000 Datasheet - Page 326

• Manufacturer Part Number: B69000
• Manufacturer: Asiliant Technologies

Specifications of B69000

• Lead Free Status / Rohs Status: Supplier Unconfirmed

Hardware Cursor and Pop Up Window
D-1
Appendix D
Hardware Cursor and Pop Up Window
This graphics controller provides a pair of hardware-based cursors, called “cursor 1” and “cursor 2.” Cursor
1 is normally used to provide the arrow pointer in most GUI applications and operating systems. Cursor 2
has no pre-assigned purpose, however it is assumed that it will be usually used to provide some form of
pop-up window.
Off-screen memory in the frame buffer is used to provide the locations where the data for both cursor 1 and
cursor 2 are kept. This allows each cursor to be displayed and used without altering the main display image
stored in the frame buffer. Each cursor may have multiple patterns stored in these off-screen memory
locations, making it possible to change each cursor’s appearance simply by switching from one stored
image to another.
Two sets of eight registers (XRA0-XRA7 for cursor 1 and XRA8-XRAF for cursor 2) provide the means to
configure and position both cursors. In each set of eight registers, two are used to enable, disable, and
configure each cursor. Another pair of registers from each set specifies the base address within the frame
buffer memory where the cursor data is kept. These registers also provide a way to select one of up to
sixteen cursor patterns to be used. The remaining four registers of each set are used to provide the X and
Y coordinates to control the current location of each cursor relative to the upper left-hand corner of the
display.
Two sets of four alternate color data positions added to the RAMDAC provide places in which the colors for
each of the two cursors are specified (positions 0-3 for cursor 2 colors 0-3, and positions 4-7 for cursor 1
colors 0-3). These alternate color data positions are accessed by the same sub-addressing scheme used
to access the standard color data positions of the main RAMDAC palette, with the exception that a bit in
Pixel Pipeline Configuration Register 0 (XR80) must be set so that the alternate color data positions are
accessible in place of the standard color data positions.
Basic Cursor Configuration
Cursor 1 and cursor 2 can each be independently disabled or configured for one of six possible modes using
the Cursor 1 Control Register (XRA0) and the Cursor 2 Control Register (XRA8). Detailed descriptions of
each of these six modes are provided later in this section.
Horizontal and/or vertical stretching are functions that may be independently enabled or disabled for each
cursor using these registers. Similar to the stretching functions used with the main display image, the
stretching functions for each of the cursors only apply to flat panel displays. When enabled, the horizontal
and vertical stretching functions for each cursor use the same stretching algorithms and parameter settings
selected in the registers used to control the horizontal and vertical stretching functions for the main display
image. The horizontal and vertical stretching functions for each cursor can be enabled or disabled entirely
independently of the horizontal and vertical stretching functions for the main display image.
These same two registers also provide the means to enable or disable blinking for each cursor, and to
choose between two possible locations on the screen for the origin of the coordinate system used to specify
the cursor location. A bit in each of these registers provides the ability to choose either the upper left-hand
corner of the active display area, or the outer-most upper left-hand corner of the display border surrounding
the active display area as the exact location of the origin for the coordinate system for each cursor.
Finally, each of these registers allows the vertical extension function to be enabled or disabled for each
cursor. The vertical extension function allows the height of the cursor to be specified independently from
its width, allowing cursors that are not square in shape to be created. This function is discussed in more
detail later in this section.
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69000 Databook
Subject to Change Without Notice
Revision 1.3 8/31/98