NH82810 S L7XK Intel, NH82810 S L7XK Datasheet - Page 43

• Manufacturer Part Number: NH82810 S L7XK
• Manufacturer: Intel

Specifications of NH82810 S L7XK

• Lead Free Status / RoHS Status: Compliant

3.4.18.
Datasheet
R
SMRAM    System Management RAM Control Register
(Device 0)
Address Offset:
Default Value:
Access:
Size:
The SMRAM register controls how accesses to Compatible and Extended SMRAM spaces are treated,
and how much (if any) memory used from the System to support both SMRAM and Graphics Local
Memory needs.
Bit
7:6
5:4
7
Graphics Mode Select
Graphics Mode Select (GMS). This field is used to enable/disable the internal graphics device and
select the amount of system memory that is used to support the internal graphics device.
00 = Graphics Device Disabled, No memory used (Device 1 is not accessible in this case)
01 = Reserved
10 = Graphics Device Enabled, 512 KB of memory used
11 = Graphics Device Enabled 1 MB of memory used
Note: When the Graphics Device is Disabled (00) the graphics device and all of its memory and I/O
functions are disabled and the clocks to this logic are turned off, memory accesses to the VGA range.
The 512 KB and 1 MB space selected by this field is used by video BIOS for handling support of VGA
when no GMCH graphics driver is present (e.g., a DOS boot).
(A0000h–BFFFFh) will be forwarded on to the hub interface, and no system memory is used to support
the internal graphics device. When this field is non-zero the graphics device of the GMCH and all of its
memory and I/O functions are enabled, all non-SMM memory accesses to the VGA range will be
handled internally and the selected amount of system memory (0, 512K or 1M) is used from system
memory to support the internal graphics device.
Once D_LCK is set, these bits becomes read only.
Upper SMM Select ( USMM ). This field is used to enable/disable the various SMM memory ranges
above 1 MB. TSEG is a block of memory (Used from System Memory at [TOM-Size] : [TOM]) that is
only accessible by the processor and only while operating in SMM mode. HSEG is a Remap of the AB
segment at FEEA0000 : FEEBFFFF. Both of these areas, when enabled, are usable as SMM RAM,
Non-SMM Operations that use these address ranges are forwarded to hub interface. HSEG is ONLY
enabled if LSMM = 00.
00 = TSEG and HSEG are both Disabled
01 = TSEG is Disabled, HSEG is Conditionally Enabled
10 = TSEG is Enabled as 512 KB and HSEG is Conditionally Enabled
11 = TSEG is Enabled as 1 MB and HSEG is Conditionally Enabled
Once D_LCK is set, these bits becomes read only.
6
5
Upper SMM Select
70h
00h
Read/Write
8 bits
4
Description
3
Lower SMM Select
2
Intel
Locked
Space
SMM
1
®
82810E (GMCH)
E_SMRA
M_ERR
0
43