GX1 Datasheet, PDF (115/247 Pages) National Semiconductor (TI) – Processor Series Low Power Integrated x86 Solution

Integrated Functions (Continued)
Table 4-15. Memory Controller Registers (Continued)
Bit
Name
Description
13
RSVD
Reserved: Set to 0.
12
DIMM0_
DIMM0 Component Banks (Banks 0 and 1): Selects the number of component banks per module
COMP_BNK bank for DIMM0:
0 = 2 Component banks
1 = 4 Component banks
Banks 0 and 1 must have the same number of component banks.
11
RSVD
Reserved: Set to 0.
10:8
DIMM0_SZ
DIMM0 Size (Banks 0 and 1): Selects the size of DIMM1:
000 = 4 MB
001 = 8 MB
010 = 16 MB
011 = 32 MB
100 = 64 MB
101 = 128 MB
110 = 256 MB
111 = 512 MB
This size is the total of both banks 0 and 1. Also, banks 0 and 1 must be the same size.
7
RSVD
Reserved: Set to 0.
6:4
DIMM0_PG_SZ DIMM0 Page Size (Banks 0 and 1): Selects the page size of DIMM0:
000 = 1 KB
001 = 2 KB
010 = 4 KB
011 = 8 KB
1xx = 16 KB
111 = DIMM0 not installed
Both banks 0 and 1 must have the same page size. When DIMM0 (neither bank 0 or 1) is not installed,
program all other DIMM0 fields to 0.
3:0
RSVD
Reserved: Set to 0.
GX_BASE+840Ch-840Fh
MC_SYNC_TIM1 (R/W)
Default Value = 2A733225h
31
30:28
27:24
23:20
19
18:16
15
14:12
11
RSVD
LTMODE
RC
RAS
RSVD
RP
RSVD
RCD
RSVD
Reserved: Set to 0.
CAS Latency (LTMODE): CAS latency is the delay, in SDRAM clock cycles, between the registration
of a read command and the availability of the first piece of output data. This parameter significantly
affects system performance. Optimal setting should be used. If DIMMs are used BIOS can interrogate
EEPROM across the I²C interface to determine this value:
000 = Reserved 010 = 2 CLK
001 = Reserved 011 = 3 CLK
100 = 4 CLK
101 = 5 CLK
110 = 6 CLK
111 = 7 CLK
This field will not take effect until SDRAMPRG (bit 0 of MC_MEM_CNTRL1) transitions from 0 to 1.
RFSH to RFSH/ACT Command Period (tRC): Minimum number of SDRAM clock between RFSH and
RFSH/ACT commands:
0000 = Reserved
0001 = 2 CLK
0010 = 3 CLK
0011 = 4 CLK
0100 = 5 CLK
0101 = 6 CLK
0110 = 7 CLK
0111 = 8 CLK
1000 = 9 CLK
1001 = 10 CLK
1010 = 11 CLK
1011 = 12 CLK
1100 = 13 CLK
1101 = 14 CLK
1110 = 15 CLK
1111 = 16 CLK
ACT to PRE Command Period (tRAS): Minimum number of SDRAM clocks between ACT and PRE
commands:
0000 = Reserved
0001 = 2 CLK
0010 = 3 CLK
0011 = 4 CLK
0100 = 5 CLK
0101 = 6 CLK
0110 = 7 CLK
0111 = 8 CLK
1000 = 9 CLK
1001 = 10 CLK
1010 = 11 CLK
1011 = 12 CLK
1100 = 13 CLK
1101 = 14 CLK
1110 = 15 CLK
1111 = 16 CLK
Reserved: Set to 0.
PRE to ACT Command Period (tRP): Minimum number of SDRAM clocks between PRE and ACT
commands:
000 = Reserved 010 = 2 CLK
001 = 1 CLK
011 = 3 CLK
100 = 4 CLK
101 = 5 CLK
110 = 6 CLK
111 = 7 CLK
Reserved: Set to 0.
Delay Time ACT to READ/WRT Command (tRCD): Minimum number of SDRAM clock between ACT
and READ/WRT commands. This parameter significantly affects system performance. Optimal setting
should be used:
000 = Reserved 010 = 2 CLK
001 = 1 CLK
011 = 3 CLK
100 = 4 CLK
101 = 5 CLK
110 = 6 CLK
111 = 7 CLK
Reserved: Set to 0.
Revision 1.0
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