Single-Chip Ethernet Controller with HP Auto-MDIX Support and PCI Interface

Datasheet

3.2.4PCI Target Interface

The PCI target interface implements the address spaces listed in Table 3.1.

 

 

Table 3.1 PCI Address Spaces

 

 

 

SPACE

SIZE

RESOURCE

 

 

 

Configuration

256 bytes

PCI standard and PCIB-specific registers

 

 

 

BAR0...BAR2

 

RESERVED

 

 

 

BAR3

1 KB

Control and Status Registers (Non-prefetchable area)

 

 

 

BAR4

256B

Control and Status Registers (I/O area)

 

 

 

BAR5

 

RESERVED

 

 

 

Expansion ROM

-

RESERVED

 

 

 

The PCI Configuration space is used to identify PCI Devices, configure memory ranges, and manage interrupts. The Host initializes and configures the PCI Device during a plug-and-play process.

The PCI Target Interface supports 32-bit slave accesses only. Non 32-bit PCI target reads to LAN9420/LAN9420i will result in a full 32-bit read. Non 32-bit PCI target writes to LAN9420/LAN9420i will be silently discarded.

3.2.4.1PCI Configuration Space Registers

PCI Configuration Space Registers include the standard PCI header registers and PCIB extensions to implement power management control/status registers. See Section 4.6, "PCI Configuration Space CSR (CONFIG CSR)," on page 149 for further details. These registers exist in the configuration space.

3.2.4.2Control and Status Registers (CSR)

The PCI Target Interface allows PCI bus masters to directly access the LAN9420/LAN9420i Control and Status registers via memory or I/O operations. Each set of operations has an associated address range that defines it as follows:

„The non-prefetchable (NP) address range is mapped in BAR3. No data prefetch is performed when serving PCI transactions targeting this address range.

„The I/O address range is mapped in BAR4.

3.2.4.2.1CSR ENDIANNESS

The Non-Prefetchable address range contains a double mapping of the CSR. These mappings allow the registers to be accessed in little endian or big endian order. Figure 3.3, "CSR Double Endian Mapping" illustrates the mapping. BA is the base address, as specified by BAR3.

Revision 1.22 (09-25-08)

26

SMSC LAN9420/LAN9420i

 

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