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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—Memory Controller
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
632
Order Number: 306262-004US
11.6.1
DDRI SDRAM Initialization Register SDIR
The DDRI SDRAM Initialization Register (SDIR) is responsible for programming the
operation of the DDRI SDRAM device state machines. The SDIR provides a method for
software to execute the DDRI SDRAM initialization sequence (see
Register Name:
DDRI SDRAM Initialization Register - SDIR
Hex Offset Address:
CC00 E500H
Reset Hex Value:
0x0000 000FH
Register Description:
DDRI SDRAM Initialization Register
Access: See below.
31
4
3
0
(Reserved)
Register
DDRI SDRAM Initialization Register - SDIR
Bits
Name
Description
Default
Access
31:0
4
(Reserved)
0
RO
03:0
0
Special DDRI SDRAM Command: These bits are used for DDRI
SDRAM initialization. See
“DDRI SDRAM Initialization” on page 598
for
details. While not in the initialization sequence, these bits must be set
to 1xxx
2
. For details on the exact DDRI SDRAM commands, refer to
Table 211, “DDRI SDRAM Commands” on page 598
.
• 0000
2
- Mode-Register-Set Command where DLL is not Reset
and CAS Latency as specified in SDCR0
• 0001
2
- Mode-Register-Set Command where DLL is Reset and
CAS Latency and Burst Length of four
• 0010
2
- Precharge-All Command: The MCU issues one
precharge-all
command to the DDRI SDRAM devices.
• 0011
2
- NOP Command: The MCU issues one
NOP
command
to the DDRI SDRAM devices.
• 0100
2
- Extended Mode-Register Set (EMRS) Command
where DLL is enabled on the DDRI SDRAM devices.
• 0101
2
- Extended Mode-Register Set (EMRS) Command
where DLL is disabled on the DDRI SDRAM devices.
• 0110
2
- Auto-Refresh Command: The MCU issues one refresh
sequence (i.e. precharge-all followed by auto-refresh command)
to the DDRI SDRAM devices.
• Others - Normal DDRI SDRAM Operation
1111
2
RW