GXM Datasheet, PDF (51/244 Pages) National Semiconductor (TI) – Geode™ GXm Processor Integrated x86 Solution with MMX Support

Processor Programming (Continued)
Table 3-11. Configuration Registers (Continued)
Bit
Name
Description
Index
B3h
B2h
B1h
B0h
SMHR Bits
A[31:24]
A[23:16]
A[15:12]
A[7:0]
SMM Header Address Bits [A31:0]: SMHR address bits [31:0] contain the physical base address
for the SMM header space. For example, bits [31:24] correspond with Index B3h
Refer to Section 3.11.4 “SMM Configuration Registers” on page 80 for more information.
Note: MAPEN (CCR3[4]) must = 1 to read or write to this register.
Index CDh, CEh, CFh
SMAR — SMM Address Region/Size Register (R/W)
Default Value = 00h
Index
CDh
CEh
CFh[7:4]
SMAR Bits
A[31:24]
A[23:16]
A[15:12]
SMM Address Region Bits [A31:A12]: SMAR address bits [31:12] contain the base address for
the SMM region.
Bits [31:24] correspond with Index CDh
Bits [23:16] correspond with Index CEh
Bits [15:12] correspond with Index CFh[7:4]
Index CFh allows simultaneous access to SMAR address regions bits SMAR[15:12] and size code
bits SIZE[3:0]. During access, the upper 4-bits of Port 23h hold SMAR[15:12].
Refer to Section 3.11.4 “SMM Configuration Registers” on page 80 for more information.
CFh[3:0]
SIZE[3:0]
SMM Region Size Bits [3:0]: SIZE bits contain the size code for the SMM region. During access
the lower 4-bits of port 23 hold SIZE[3:0]. Index CFh allows simultaneous access to SMAR address
regions bits SMAR[15:12] (see above) and size code bits.
0000 = SMM Disabled
0001 = 4 KB
0010 = 8 KB
0011 = 16 KB
0001)
0100 = 32 KB
0101 = 64 KB
0110 = 128 KB
0111 = 256 KB
1000 = 512 KB
1001 = 1 MB
1010 = 2 MB
1011 = 4 MB
1100 = 8 MB
1101 = 16 MB
1110 = 32 MB
1111 = 4 KB (same as
Note: SMI_LOCK (CCR3[0]) must = 0, or the CPU must be in SMI mode, to write these registers/bits.
Index FEh
DIR0 — Device Identification Register 0 (RO)
Default Value = 4xh
7:4
DID[3:0]
Device ID (Read Only): Identifies device as GXm processor.
3:0
MULT[3:0]
Core Multiplier (Read Only) — Identifies the core multiplier set by the CLKMODE[2:0] pins (see
signal descriptions page 21)
If DIR1 (Index FFh) is 30h-4Fh then MULT[3:0]:
0000 = SYSCLK multiplied by 4 (Test mode only)
0001 = SYSCLK multiplied by 6
0010 = SYSCLK multiplied by 4 (Test mode only)
0011 = SYSCLK multiplied by 6
0100 = SYSCLK multiplied by 7
0101 = SYSCLK multiplied by 8
0110 = SYSCLK multiplied by 7
0111 = SYSCLK multiplied by 5
1xxx = Reserved
If DIR1 (Index FFh) is 50h or greater then MULT[3:0]:
0000 = SYSCLK multiplied by 4 (Test mode only)
0001 = SYSCLK multiplied by 10
0010 = SYSCLK multiplied by 4 (Test mode only)
0011 = SYSCLK multiplied by 6
0100 = SYSCLK multiplied by 9
0101 = SYSCLK multiplied by 5
0110 = SYSCLK multiplied by 7
0111 = SYSCLK multiplied by 8
1xxx = Reserved
Index FFh
DIR1 -- Device Identification Register 1 (RO)
Default Value = xxh
7:0
DIR1
Device Identification Revision (Read Only) — DIR1 indicates device revision number.
If DIR1 is 30h-33h = GXm processor revision 1.0 - 2.3
If DIR1 is 34h-4Fh = GXm processor revision 2.4 - 3.x
If DIR1 is 50h or greater = GXm processor revision 5.0 - 5.4..
Revision 3.1
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