Intel® IXP42X product line and IXC1100 control plane processors—Internal Bus
Intel® IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
DM September 2006
206 Order Number: 252480-006US
Table 96. Memory Map
Start Address End Address Size Use
0000_0000 0FFF_FFFF 256 MB Expansion Bus Data (Mirrored)/SDRAM Data†
1000_0000 2FFF_FFFF 768 MB SDRAM Data (Aliased)†
3000_0000 3FFF_FFFF 256 MB (Reserved)
4000_0000 47FF_FFFF 128 MB (Reserved)
4800_0000 4FFF_FFFF 128 MB PCI Data
5000_0000 5FFF_FFFF 256 MB Expansion Bus Data
6000_0000 63FF_FFFF 64 MB Queue manager
6400_0000 BFFF_FFFF (Reserved)
C000_0000 C3FF_FFFF 64 MB PCI Controller Configuration and Status Registers
C400_0000 C7FF_FFFF 64 MB Expansion Bus Configuration Registers
C800_0000 C800_0FFF 1 KB High-Speed UART
C800_1000 C800_1FFF 1 KB Console UART
C800_2000 C800_2FFF 1 KB Internal Bus Performance Monitoring Unit
C800_3000 C800_3FFF 1 KB Interrupt Controller
C800_4000 C800_4FFF 1 KB GPIO Controller
C800_5000 C800_5FFF 1 KB Timers
C800_6000 C800_6FFF 1 KB WAN/Voice NPE = NPE-A (IXP400 software
Definition)– Not User Programmable
C800_7000 C800_7FFF 1 KB Ethernet NPE A = NPE-B (IXP400 software
Definition) – Not User Programmable
C800_8000 C800_8FFF 1 KB Ethernet NPE B = NPE-C (IXP400 software
Definition) – Not User Programmable
C800_9000 C800_9FFF 1 KB Ethernet MAC A
C800_A000 C800_AFFF 1 KB Ethernet MAC B
C800_B000 C800_BFFF 1 KB USB Controller
C800_C000 C800_FFFF (Reserved)
C801_0000 CBFF_FFFF (Reserved)
CC00_0000 CC00_00FF 256 Byte SDRAM Configuration Registers
CC00_0100 FFFF_FFFF (Reserved)
† The lowest 256 MB of address space is configurable based on the value of a configuration register
located in the Expansion Bus Controller.
• When bit 31 (MEM_MAP) of configuration register #0 (EXP_CNFG0) is set to logic 1, the Expansion Bus
occupies the lowest 256 MB of address space.
• When bit 31 (MEM_MAP) of configuration register #0 (EXP_CNFG0) is set to logic 0 the Expansion Bus
occupies 256 MB of address space starting at 5000_0000 while the SDRAM occupies the lowest 256 MB
of address address space
In both cases, regardless of the value of MEM_MAP, the SDRAM occupies the 768MB (1000_0000 to
2FFF_FFFF) immediately following the lowest 256 MB and the Expansion Bus can be accessed starting
at address 5000_0000.
The largest SDRAM memory size supported by the Intel® IXP42X product line and IXC1100 control
plane processors is 256MB. The actual memory implemented in any given configuration will be aliased
(repeated) to fill the 1 GB SDRAM address space. Due to aliasing, all of the SDRAM will be accessible
even when the Expansion Bus occupies the lowest 256MB of address space. On reset, bit 31
(MEM_MAP) of configuration register #0 (EXP_CNFG0) in the Expansion Bus will be set to logic 1. This
setting is required because the dedicated boot memory is flash memory located on the Expansion Bus.
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