Local Expansion Bus (Leb) Interface; Leb Chip Select Assignment - Intel EP80579 Manual

22.0

Local Expansion Bus (LEB) Interface

The EP80579 Local Expansion Bus (LEB) is a flexible, general purpose communication
interface between the EP80579 and external peripherals. LEB is specifically designed
for compatibility with Intel and Motorola*-style microprocessor interfaces, as well as
Texas Instruments* DSP standard Host-Port Interfaces* (HPI).
The LEB controller supports 25-bit address bus and 16-bit data bus, running at a
maximum speed of 80 MHz feed in from an external clock oscillator. At 80 MHz, the
maximum load on the bus is limited to a max of two devices. At lower speeds the
number of devices can be increased as shown in the Development Board, which runs at
33 MHz.
The LEB is a flexible and multifunction bus, which can support various modes of
operation, such as target devices shown in the following table:
Intel multiplexed
Intel StrataFlash
Micron* Flow-Through ZBT
Motorola non multiplexed
The LEB controller has an address decoder, which can generate up to 8 programmable
Chip Selects (CS); each one of them able to support up to 32Mbyte of address space.
All supported modes are seamless and no additional glue logic is required. Other cycles,
such as 8-bit access or 16-bit types, may be supported by configuring the Timing and
Control Register for Chip Select. There is no support for 32-bit or wider transaction
accesses.
22.1

LEB Chip Select Assignment

Each Chip Select is connected to a device that can be independently mapped into a
contiguous IA-32 address space in blocks of 1 K to 32 MB. The eight Chip Selects can
address up to 256 MB of contiguous IA-32 address space. The start address of these
blocks is hard-coded on the 32 MB boundaries and no other device may be inserted into
the address space occupied by the particular CS.
The Development Board makes full use of all eight CS signals EX_CS[7:0]#. The
assignment of all CS signals to the various peripherals on board appears below.
EX_CS[7:0]#
EX_CS0#
EX_CS[2:1]#
EX_CS3#
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Intel EP80579 Integrated Processor Product Line
Platform Design Guide
237
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Intel EP80579 Integrated Processor Product Line—Local Expansion Bus (LEB) Interface
Intel non-multiplexed
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Synchronous Intel StrataFlash
Motorola multiplexed
Texas Instruments* Host Port Interface (HPI)
Chip Select Signal
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Memory
Peripheral
FPGA
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Flash 1, Intel StrataFlash P30
Compact Flash
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Flash 2, Intel StrataFlash P30
May 2010
Order Number: 320068-005US