B69000 Asiliant Technologies, B69000 Datasheet - Page 328

• Manufacturer Part Number: B69000
• Manufacturer: Asiliant Technologies

Specifications of B69000

• Lead Free Status / Rohs Status: Supplier Unconfirmed

Cursor Positioning
Registers XRA4-XRA7 and registers XRAC-XRAF are used to position cursor 1 and cursor 2, respectively,
on the display. Two registers from each group provide the high and low bytes for the value specifying the
horizontal position and the other two provide the high and low bytes for the value specifying the vertical
position.
A bit in one of the configuration registers (XRA0 for cursor 1 and XRA8 for cursor 2) selects whether the
values programmed into these registers are interpreted as being relative to the upper left-hand corner of the
active display area or to the outer-most upper left-hand corner of the border surrounding the active display
area.
The values provided to these registers are signed 12-bit integers. Since the origin of the coordinate system
is generally relative to the upper left corner of the display, a cursor appearing entirely within the active
display area will have a positive horizontal position value and a negative vertical position value.
These registers are double-buffered and synchronized to VSYNC to ensure that the cursor never appears
to come apart in multiple fragments as it is being moved across the screen. To change a cursor position,
all four of its position registers must be written, and they must be written in sequence (that is, in order from
XRA4 to XRA7 for cursor 1 and in order from XRAC to XRAF for cursor 2.) The hardware will only update
the position with the next VSYNC if the registers are written in sequence.
Cursor Modes
Each cursor can be independently disabled or set to one of six possible modes. This is done by using bits
2-0 in XRA0 for cursor 1 and in XRA8 for cursor 2. The main features which distinguish these modes from
each other are the manner in which the cursor data is organized in memory and the meaning of the bits
corresponding to each pixel position. The six possible modes are:
The first two modes are designed to follow the Microsoft Windows
the work of programming the cursor(s) for that particular GUI environment. The other four modes are
intended to improve upon the first two modes by providing additional color options or a larger resolution.
The following pages discuss the various modes in greater detail.
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69000 Databook
32x32x2bpp AND/XOR pixel plane mode
64x64x2bpp AND/XOR pixel plane mode
64x64x2bpp 4-color mode
64x64x2bpp 3-color and transparency mode
128x128x1bpp 2-color mode
128x128x1bpp 1-color and transparency mode
Hardware Cursor and Pop Up Window
Subject to Change Without Notice
2-plane cursor data structure to ease
Revision 1.3 8/31/98
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