GX1 Datasheet, PDF (145/247 Pages) National Semiconductor (TI) – Processor Series Low Power Integrated x86 Solution

Integrated Functions (Continued)
Table 4-29. Display Controller Configuration and Status Registers (Continued)
Bit
Name
Description
11:8
DFIFO
Display FIFO High Priority Start Level: This field specifies the depth of the display FIFO (in 64-bit entries
HI-PRI
x 4) at which a high-priority request will be sent to the memory controller to fill up the FIFO. The value is
START LVL dependent upon display mode.
This register should always be nonzero and should be less than the high-priority end level.
7:6
DCLK_
DCLK Divider: This 2-bit field specifies the clock divider for the input DCLK pin.
DIV
00 = Forced Low
01 = DCLK ÷ 2
10 = DCLK
11 = DCLK
5
DECE
Decompression Enable: Allow operation of internal decompression hardware:
0 = Disable; 1 = Enable.
4
CMPE
Compression Enable: Allow operation of internal compression hardware: 0 = Disable; 1 = Enable
3
PPC
Pixel Panning Compatibility: This bit has the same function as that found in the VGA.
Allow pixel alignment to change when crossing a split-screen boundary - it will force the pixel alignment to
be 16-byte aligned: 0 = Disable; 1 = Enable.
If disabled, the previous alignment will be preserved when crossing a split-screen boundary.
2
DVCK
Divide Video Clock: Selects frequency of VID_CLK pin:
0 = VID_CLK pin frequency is equal to one-half (½) the frequency of the core clock.
1 = VID_CLK pin frequency is equal to one-fourth (¼) the frequency of the core clock.
Bit 28 (VIDE) must be set to 1 for this bit to be valid.
1
CURE
Cursor Enable: Use internal hardware cursor: 0 = Disable; 1 = Enable.
0
DFLE
Display FIFO Load Enable: Allow the display FIFO to be loaded from memory:
0 = Disable; 1 = Enable.
If disabled, no write or read operations will occur to the display FIFO.
If enabled, a flat panel should be powered down prior to setting this bit low. Similarly, if active, a CRT should
be blanked prior to setting this bit low.
GX_BASE+8308h-830Bh
DC_TIMING_CFG Register (R/W) (Locked)
Default Value = xxx00000h
31
30
29
28
27
26:20
19:17
16
VINT
(RO)
VNA
(RO)
DNA
(RO)
RSVD
DDCI
(RO)
RSVD
RSVD
BKRT
Vertical Interrupt (Read Only): Is a vertical interrupt pending? 0 = No; 1 = Yes.
This bit is provided to maintain backward compatibility with the VGA. It corresponds to VGA port 3C2h bit 7.
Vertical Not Active (Read Only): Is the active part of a vertical scan is in progress (i.e., retrace, blanking,
or border)? 0 = Yes; 1 = No.
This bit is provided to maintain backward compatibility with the VGA. It corresponds to VGA port 3BA/3DA
bit 3.
Display Not Active (Read Only): Is the active part of a line is being displayed (i.e., retrace, blanking, or
border)? 0 = Yes; 1 = No.
This bit is provided to maintain backward compatibility with the VGA. It corresponds to VGA port 3BA/3DA
bit 0.
Reserved: Set to 0.
DDC Input (Read Only): This bit returns the value from the DDCIN pin that should reflect the value from
pin 12 of the VGA connector. It is used to provide support for the VESA Display Data Channel standard
level DDC1.
Reserved: Set to 0.
Reserved: Set to 0.
Blink Rate:
0 = Cursor blinks on every 16 frames for a duration of 8 frames (approximately 4 times per second) and
VGA text characters will blink on every 32 frames for a duration of 16 frames (approximately 2 times per
second).
1 = Cursor blinks on every 32 frames for a duration of 16 frames (approximately 2 times per second) and
VGA text characters blink on every 64 frames for a duration of 32 frames (approximately 1 time per sec-
ond).
Blinking is enabled by BLNK bit 7.
Revision 1.0
145
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