Filter
Top Products
AMD Geode™ LX Processors Data Book 283
Display Controller
33234H
6.5.1.2 Display FIFO
The DC module incorporates a 512-entry x 64-bit display
FIFO that queues up all display data, including graphics
frame buffer data, compressed display buffer data, cursor
and icon overlay data, and video overlay YUV data. When
the video output port is enabled, 32 slots of the display
FIFO are allocated for the video transfer buffer.
The DFHPSL and DFHPEL (DC Memory Offset 004h[11:8]
and [15:12]) bits are used to set the thresholds for high-pri-
ority memory request assertion. These levels can be tuned
for a particular display mode to optimize memory band-
width utilization.
6.5.1.3 Hardware Cursor and Icon Overlays
The GUI supports a 64x64x2-bit hardware cursor overlay.
The 2-bit codes are defined in Table 6-33.
A hardware icon overlay is also supported for applications
that require a fixed sprite overlay. This is particularly useful
in portable applications for display status indicators that are
independent of the application that is running. When
enabled, the icon overlay is displayed on each active scan
line. The icon is 64 pixels wide and supports three colors
plus transparency as shown in Table 6-34.
The display of cursor and icon overlays is controlled by
CURE (bit 1) and CLR_CUR (bit 2) in DC_GENERAL_CFG
(DC Memory Offset 004h), which take effect on the next
vertical sync after the bits are programmed. The cursor is
always displayed on top of the icon if both are enabled.
The cursor and icon are inserted into the graphics stream
prior to mixing the video overlay data. Since the back-
ground color-keyed value generally does not match the
cursor or icon colors, the cursor and icon may be displayed
on top of any active video. Note that the cursor and icon
features are not available in VGA modes.
Table 6-33. Cursor Display Encodings
AND Mask XOR Mask Color Displayed
0 0 Cursor Color 0 - Palette Index 100h
0 1 Cursor Color 1 - Palette Index 101h
1 0 Transparent - Background Pixel
1 1 Inverted - Bitwise Inversion of Background Pixel
Table 6-34. Icon Display Encodings
AND Mask XOR Mask Color Displayed
0 0 Icon Color 0 - Palette Index 102h
0 1 Icon Color 1 - Palette Index 103h
1 0 Transparent - Background Pixel
1 1 Border Color - Palette Index 104h