GXM Datasheet, PDF (128/244 Pages) National Semiconductor (TI) – Geode™ GXm Processor Integrated x86 Solution with MMX Support

Integrated Functions (Continued)
Table 4-25. Graphics Pipeline Configuration Registers (Continued)
Bit
Name Description
GX_BASE+820Ch-820Fh
GP_BLT_STATUS Register (R/W)
Default Value = 00000000h
31:10
9
8
7:3
2
1
0
RSVD
W
M
RSVD
BP (RO)
PB (RO)
BB (RO)
Reserved: Set to 0.
Screen Width: Selects a frame-buffer width of 2048 bytes (default is 1024 bytes).
16-BPP Mode: Selects a pixel data format of 16 BPP (default is 8 BPP).
Reserved: Set to 0.
BLT Pending (Read Only): Indicates that a BLT operation is pending in the master registers.
The “BLT Pending” bit must be clear before loading any of the graphics pipeline registers. Loading registers
when this bit is set high will destroy the values for the pending BLT.
Pipeline Busy (Read Only): Indicates that the graphics pipeline is processing data.
The “Pipeline Busy” bit differs from the “BLT Busy” bit in that the former only indicates that the graphics pipe-
line is processing data. The “BLT Busy” bit also indicates that the memory controller has not yet processed
all of the requests for the current operation.
The “Pipeline Busy” bit must be clear before loading a BLT buffer if the previous BLT operation used the
same BLT buffer.
BLT Busy (Read Only): Indicates that a BLT / vector operation is in progress.
The “BLT Busy” bit must be clear before accessing the frame buffer directly.
GX_BASE+8210h-8213h
GP_VGA_BASE (R/W)
Default Value = xxxxxxxxh
Note that the registers at GX_BASE+8210h and 8214h are located in the area designated for the graphics pipeline but are used for
VGA emulation purposes. Refer to Table 5-5 on page 173 for these register’s bit formats.
GX_BASE+8214h-8217h
GP_VGA_LATCH Register (R/W)
Default Value = xxxxxxxxh
Note that the registers at GX_BASE+8210h and 8214h are located in the area designated for the graphics pipeline but are used for
VGA emulation purposes. Refer to Table 5-5 on page 173 for these register’s bit formats.
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