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4 writememoryaperture, 5 readmemoryaperture, 6 blinkcounterctl – AMD Geode LX [email protected] User Manual

Page 386: Writememoryaperture, Readmemoryaperture, Blinkcounterctl, Blinkcounterctl (f

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386

AMD Geode™ LX Processors Data Book

Display Controller Register Descriptions

33234H

6.6.23.4 WriteMemoryAperture

6.6.23.5 ReadMemoryAperture

6.6.23.6 BlinkCounterCtl

This register is for simulation and test only.

CRTC Index

047h

Type

R/W

Reset Value

00h

WriteMemoryAperture Register Bit Descriptions

Bit

Name

Description

7:0

WR_BASE

WriteBase. Offset added to the graphics memory base to specify where VGA write oper-
ations start. This value provides DWORD address bits [21:14] when mapping host VGA
writes to graphics memory. This allows the VGA base address to start on any 64 KB
boundary within the 8 MB of graphics memory.

CRTC Index

048h

Type

R/W

Reset Value

00h

ReadMemoryAperture Register Bit Descriptions

Bit

Name

Description

7:0

RD_BASE

ReadBase. Offset added to the graphics memory base to specify where VGA read oper-
ations start. This value provides DWORD address bits [21:14] when mapping host VGA
reads to graphics memory. This allows the VGA base address to start on any 64 KB
boundary within the 8 MB of graphics memory.

CRTC Index

060h

Type

R/W

Reset Value

00h

BlinkCounterCtl Register Bit Descriptions

Bit

Name

Description

7

HLD_CNT

Hold Count. When set, prevents the blink counter from incrementing with each leading
edge VSYNC.

6:5

RSVD

Reserved.

4:0

BLNK_CNT

Blink Count. The blink counter is loaded with this value while the Sequencer Reset reg-
ister is in the reset state.

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