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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—Expansion Bus
Controller
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
712
Order Number: 306262-004US
Under software control, bits 0 and 1 allow interrupts to be generated to the Interrupt
Controller.
When byte swapping is enabled, byte 3 of a a word is swapped with byte 0, and byte 1
is swapped with byte 2.
10
EXP_BYTE_SWAP_EN
Enables byte swapping for EXP inbound transfers. This swapping
occurs regardless of the Intel XScale processor endianism.
0 = byte swapping disabled
1 = byte swapping enabled
9
FORCE_BYTE_SWAP
Forces byte swapping on Intel XScale processor initiated accesses
in little-endian mode regardless of the P-attribute bit.
0 = do not force byte swapping
1 = force byte swapping on all transfers regardless of the P-
attribute bit in little-endian mode. When this bit is set,
BYTE_SWAP_EN is ignored and byte swapping always happens in
little-endian mode.
8
BYTE_SWAP_EN
Sets byte swapping at the on Intel XScale processor initiated
accesses
0 = byte swapping disabled
1 = byte swapping enabled
Note:
See note, below.
7:2
(Reserved)
(Reserved)
1
SW_INT1
0 = Disable interrupt
1 = Generate interrupt
0
SW_INT0
0 = Disable interrupt
1 = Generate interrupt
Table 231.
Expansion Bus Configuration Register 1-Bit Definition (Sheet 3 of 3)
Bit
Name
Description
Note:
For transactions initiated by the Intel XScale
®
Processor, the selection between address or data
coherency is controlled by a software-programmable, P-attribute bit in the Intel
®
IXP4XX Product
Line Memory Management Unit (MMU) and the BYTE_SWAP_EN bit. The BYTE_SWAP_EN bit will be
from Expansion bus controller Configuration Register 1, Bit 8. This bit will reset to 0.
The default endian conversion method for IXP45X/IXP46X network processors is address coherency.
This was selected to enable backward compatible with the Intel
®
IXP425 processor.
The BYTE_SWAP_EN bit is an enable bit that enables data coherency to be performed, based on the
P-attribute bit.
When the bit is 0, address coherency is always performed.
When the bit is 1, the type of coherency depends on the P-attribute bit.
The P-attribute bit is associated with each 1-Mbyte page. The P-attribute bit is output, from the Intel
XScale processor, with any store or load access associated with that page.
Note:
When enabling SMII mode for the NPE’s during boot-up, the NPE’s will need to be reset in software
to ensure a clean transition into SMII mode. Software must execute the following code when
entering SMII mode:
1.
Write the Expansion EXP_UNIT_FUSE_RESET register to turn ON the reset for the NPE's.
2.
If the PCI interface is not used, the PCI RCOMP bit of the EXP_UNIT_FUSE_RESET register must be
set to a ‘1’. If the PCI interface is used, the PCI RCOMP bit must be left unchanged at logic ‘0’.
3.
Read the SMII_RCOMP_CSR register, set bit 16 to ‘1’, and write value back to SMII_RCOMP_CSR
register.
4.
Write the EXP_SMIIDLL register to enable the DLL.
5.
Write the Expansion EXP_CNFG1 register to turn on SMII mode for the appropriate NPE's (SMII
mode for NPE-B must be enabled for SMII mode to work on NPE-A or NPE-C)
6.
Read the Expansion EXP_CNFG1 register to ensure previous write has occurred
7.
Wait at least 1000 ns
8.
Write the Expansion EXP_UNIT_FUSE_RESET register to turn OFF the reset for the NPE's.
9.
Resume normal boot-up
10.
Wait at least 12ms before starting Ethernet traffic on ports that have SMII enabled, since it takes 12
ms for the SMII pins to stabilize.