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230 AMD Geode™ LX Processors Data Book
GeodeLink™ Memory Controller Register Descriptions
33234H
MC_CF8F_DATA Bit Descriptions
Bit Name Description
63:56 STALE_REQ GLIU Max Stale Request Count. Non-high priority requests (PRI = 0) are made high-pri-
ority requests when the request is not serviced within max stale request count clocks.
(Default = 18h)
55:53 RSVD Reserved.
52:51 XOR_BIT_SEL XOR Bit Select. Selects which upper GLIU address bit to XOR with MB0, BA1 or BA0
(see "Auto Low Order Interleaving" on page 212). Only applies to LOI mode. (Default =
00).
00: ADDR[18] 01: ADDR[19] 10: ADDR[20] 11: ADDR[21]
50 XOR_MB0 XOR MB0 Enable. Enables XORing of module bank select MB0 with upper GLIU
address bit selected by XOR_BIT_SEL (bits [52:51]). (Default = 0, Disabled)
49 XOR_BA1 XOR BA1 Enable. Enables XORing of component bank select BA1 with upper GLIU
address bit selected by XOR_BIT_SEL (bits [52:51]). (Default = 0, Disabled)
48 XOR_BA0 XOR BA0 Enable. Enables XORing of component bank select BA0 with upper GLIU
address bit selected by XOR_BIT_SEL (bits [52:51]). (Default = 0, Disabled)
47:42 RSVD Reserved.
41 TRUNC_DIS Burst Truncate Disable. Disables truncation of read/write bursts. This disable reduces
performance and should only be used during debug. (Default = 0, bursts enabled)
40 REORDER_DIS Reorder Disable. Disables the reordering of requests. This bit must be set to 1.
39:34 RSVD Reserved.
33 HOI_LOI High / Low Order Interleave Select (HOI / LOI). Selects the address interleaving mode.
HOI uses fixed upper address bits to map the GLIU address to a component bank. LOI
uses variable lower address bits depending on page size, number of module banks, and
number of component banks of the DIMMs, plus an option to XOR with upper address
bits.
1: HOI.
0: LOI. (Default)
32 RSVD Reserved.
31 THZ_DLY tHZ Delay. Add 1 extra clock on read-to-write turnarounds to satisfy DRAM parameter
t
HZ
for higher frequencies. (Default = 0)
30:28 CAS_LAT Read CAS Latency. Number of clock delays between Read command and Data valid.
CAS Latency:
000: RSVD 010: 2 (Default) 100: 4 110: 2.5
001: RSVD 011: 3 101: 1.5 111: 3.5
27:24 ACT2ACTREF ACT to ACT/REF Period. tRC. Minimum number of SDRAM clocks between ACTIVE
and ACTIVE/AUTO REFRESH commands. (Default = 8h)
23:20 ACT2PRE ACT to PRE Period. tRAS. Minimum number of clocks from ACT to PRE commands on
the same component bank. (Default = 7h)
19 RSVD Reserved.
18:16 PRE2ACT Pre to Act Period. tRP. Minimum number of SDRAM clocks between PRE and ACT com-
mands. (Default = 011)
15 RSVD Reserved.
14:12 ACT2CMD Delay Time from Act To read/WRITE. tRCD. Minimum number of SDRAM clocks
between ACT and READ/WRITE commands. (6..2 valid). (Default = 011)