AMD Geode LX 800@0.9W - Manual (Page 333)

AMD Geode™ LX Processors Data Book 333
Display Controller Register Descriptions 33234H
6.6.6.2 DC Cursor Y Position (DC_CURSOR_Y)
This register contains the Y position information of the hardware cursor.
Settings written to this register will not take effect until the start of the following frame or interlaced field.
6.6.6.3 DC Line Count/Status (DC_LINE_CNT/STATUS)
This register contains status information for the current display state, including the current scan line for the display
(V_LINE_CNT). This portion of the register is read only and is used by software to time update the frame buffer to avoid
tearing artifacts. This scan line value is driven directly off of the Dot clock, and consequently it is not synchronized with the
CPU clock. Software should read this register twice and compare the result to ensure that the value is not transitioning.
Several additional read only display status bits are provided to allow software to properly time the programming of registers
and to detect the source of display generated interrupts.
16:11 X_OFFSET X Offset. This field represents the X pixel offset within the 64x64 cursor pattern at which
the displayed portion of the cursor is to begin. Normally, this value is set to zero to dis-
play the entire cursor pattern, but for cursors for which the “hot spot” is not at the left
edge of the pattern, it may be necessary to display the right-most pixels of the cursor only
as the cursor moves close to the left edge of the display.
10:0 CURSOR_X Cursor X. This field represents the X coordinate of the pixel at which the upper left cor-
ner of the cursor is to be displayed. This value is referenced to the screen origin (0,0),
which is the pixel in the upper left corner of the screen.
DC Memory Offset 064h
Type
R/W
Reset Value xxxxxxxxh
DC_CURSOR_X Bit Descriptions
Bit Name Description
DC_CURSOR_Y Register Map
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RSVD Y_OFFSET CURSOR_Y
DC_CURSOR_Y Bit Descriptions
Bit Name Description
31:17 RSVD Reserved.
16:11 Y_OFFSET Y Offset. This field represents the Y line offset within the 64x64 cursor pattern at which
the displayed portion of the cursor is to begin. Normally, this value is set to zero to dis-
play the entire cursor pattern, but for cursors for which the “hot spot” is not at the top
edge of the pattern, it may be necessary to display the bottom-most lines of the cursor
only as the cursor moves close to the top edge of the display. Note that if this value is
non-zero, the DC_CURS_ST_OFFSET (DC Memory Offset 018h) must be set to point to
the first cursor line to be displayed.
10:0 CURSOR_Y Cursor Y. This field represents the Y coordinate of the line at which the upper left corner
of the cursor is to be displayed. This value is referenced to the screen origin (0,0), which
is the pixel in the upper left corner of the screen.
DC Memory Offset 06Ch
Type
RO
Reset Value xxxxxxxxh