Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
629
DDR SDRAM Memory Controller—Intel
®
81341 and 81342
10:08
000
2
CAS:
Indicates the CAS Latency used by the Memory Controller state machine.
Equation 23.CAS = tCAS - 1
where tCAS is from SPD.
000 = Reserved.
001 = Reserved.
010 = 3 MCLK periods (DDR2 Type only)
011 = 4 MCLK periods (DDR2 Type only)
100 = 5 MCLK periods (DDR2 Type only)
All other values are reserved and not supported.
Note:
When ODT is enabled CAS Latency must be equal to or greater than 4.
07
0
2
Reset read FIFO. Writing a 0 to this bit causes the FIFO to be reset.
0 = Reset FIFO
1 = Normal Operation
06
0
2
Internal Bus Address Map Control — This bit controls how the internal bus address is mapped to the
Bank Address/Row Address/Column Address of the DDR2 SDRAM Memory. Refer to
“DDR SDRAM Addressing” on page 575
05:04
00
2
ODT Termination Value: Determines the termination value of the On Die Termination for both Banks
(controlled by
ODT[1:0]
). Applies to DDR2 SDRAM memory type only.
• 00 Disabled
• 01 75 ohm
• 10 150 ohm
• 11 reserved
03
0
2
Reserved.
02
0
2
DDR Type. Only reflects DDR2 for 81341 and 81342.
01
0
2
Data Bus Width:
Indicates the width of the data bus.
See
Section 7.3.3.4, “32-bit Data Bus Width” on page 588
.
0 = 64 bits
1 = 32 bits
00
0
2
DIMM Type:
Selects unbuffered or registered DIMM operating modes for the DMCU.
0 = Unbuffered
1 = Registered (must always be set for 81341 and 81342)
Note:
The DMCU on
81341 and 81342 must always be programmed to operate in Registered mode.
Hence, this bit must be set. When interfacing with unbuffered DIMM type, software must set bit
DLLRCVER[16]. Refer to
“DLL Delay for Receive Enable Register — DLLRCVER” on page 665
Table 375. DDR SDRAM Control Register 0 — SDCR0 (Sheet 2 of 2)
Bit
Default
Description
PCI
IOP
Attributes
Attributes
28
24
20
16
12
8
4
0
31
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rv
na
rw
na
rw
na
rw
na
rv
na
rw
na
rw
na
rw
na
rv
na
rv
na
rw
na
rw
na
rv
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rv
na
ro
na
rw
na
rw
na
Attribute Legend:
RV = Reserved
PR = Preserved
RS = Read/Set
RW = Read/Write
RC = Read Clear
RO = Read Only
NA = Not Accessible
Intel XScale
®
microarchitecture Local Bus
Address offset
+1804H