GXM Datasheet, PDF (143/244 Pages) National Semiconductor (TI) – Geode™ GXm Processor Integrated x86 Solution with MMX Support

Integrated Functions (Continued)
Table 4-30. Display Controller Configuration and Status Registers (Continued)
Bit
Name
Description
12
PDEL
Panel Data Enable Low:
0 = This bit will cause the PANEL[8:0] data bus to be driven to a logic low level to effectively blank an
attached flat panel display or disable the lower panel data bus if it is not required.
1= If no flat panel is attached, the PANEL[8:0] data bus will be driven with active pixel data. If a flat panel is
attached, setting this bit high will have no effect − the lower panel bus will be driven based upon the power
sequencing logic.
11
PRMP
Palette Re-map:
0 = The modified codes are sent to the RAMDAC and the external palette should uses the modified map-
ping.
1 = Bits [8:1] of the palette output register are routed to the RAMDAC data bus. The GXm processor inter-
nal palette RAM may be loaded with 8-bit VGA indices to translate the modified codes stored in display
memory so that the RAMDAC data bus will contain the expected indices. The modified codes are used to
achieve character blinking in VGA text modes. This mode should be set high set high only for desktop sys-
tems with no flat panel attached. It should only be necessary when 8514/A or VESA standard feature con-
nector support is required.
10
CKSL
Clock Select: Selects output used to clock PANEL[17:0], FPHSYNC, FPVSYNC, and ENADISP output
pins.
1 = PCLK
0 = FPCLK (based upon the power sequencing logic)
This bit should be high when using a 16-bit RAMDAC.
9
FRMS
Frame Rate Modulation Select:
0 = Enables FRM circuitry to change the pattern displayed every frame.
1 = Enables FRM circuitry to change the pattern displayed every two frames (to allow for slower response
time liquid crystal materials).
8
3/4ADD 3- or 4-bit Add:
0 = Enables dither and FRM circuitry to operate on the 3 most significant bits of each color component for
9-bit TFT panels.
1 = Enables the dither and FRM circuitry to operate on the 4 most significant bits of each color component
for 12-bit TFT panels.
7
RSVD
Reserved: Must be set to 0.
6
RSVD
Reserved: Must be set to 0.
5
RSVD
Reserved: Must be set to 0.
4
DITE
Dither Enable: Allow a 2x2 spatial dither on the 3-bit or 4-bit color value. Note that dither will not be sup-
ported for 12-bit TFT panels when FRM is enabled. 0 = Disable; 1 = Enable.
3
FRME
Frame-Rate Modulation Enable: Allow FRM to be performed on the 3-bit or 4-bit color value using the
next most significant bit after the least significant bit sent to the panel.
0 = Disable (no FRM performed);
1 = Enable.
2
PCKE
PCLK Enable:
0 = PCLK is disabled and a low logic level is driven off-chip. Also, the RAMDAC data bus is driven low.
1 = Enable PCLK to be driven off-chip.
This clock operates the RAMDAC interface.
1
16FMT
16 BPP Format: Selects RGB display mode:
0 = RGB 5-6-5 mode
1 = RGB 5-5-5 display mode
This bit is only significant if 8 BPP is low, indicating 16 BPP mode.
0
8BPP
8 BPP / 16 BPP Select:
0 = 16-bit per pixel display mode is selected. (Bit 1 of OUTPUT_CONFIG will indicate the format of the 16
bit data.)
1 = 8-bit-per-pixel display mode is selected. This is the also the mode used in VGA emulation.
Revision 3.1
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