PRIXP423ABD Intel, PRIXP423ABD Datasheet - Page 22



Manufacturer Part Number

Specifications of PRIXP423ABD

Core Operating Frequency
Package Type
Pin Count
Surface Mount
Operating Temperature (max)
Operating Temperature (min)
Operating Temperature Classification
Lead Free Status / Rohs Status
IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
of Network Processors and IXC1100 Control Plane Processor Developer’s Manual.)
SDRAM Controller
The memory controller manages the interface to external SDRAM memory chips. The
The memory controller only supports 32-bit memory. If a x16 memory chip is used, a
minimum of two memory chips would be required to facilitate the 32-bit interface
required by the IXP42X product line and IXC1100 control plane processors. A maximum
of four SDRAM memory chips may be attached to the processors. For more information
on SDRAM support and configuration see the Intel
Processors and IXC1100 Control Plane Processor Developer’s Manual.
The memory controller internally interfaces to the North AHB and South AHB with
independent interfaces. This architecture allows SDRAM transfers to be interleaved and
pipelined to achieve maximum possible efficiency.
The maximum burst size supported to the SDRAM interface is eight 32-bit words. This
burst size allows the best efficiency/fairness performance between accesses from the
North AHB and the South AHB.
Expansion Bus
The expansion interface allows easy and — in most cases — glue-less connection to
peripheral devices. It also provides input information for device configuration after
reset. Some of the peripheral device types are flash, ATM control interfaces, and DSPs
used for voice applications. (Some voice configurations can be supported by the HSS
interfaces and the Intel XScale
The expansion bus interface is a 16-bit interface that allows an address range of
512 bytes to 16 Mbytes, using 24 address lines for each of the eight independent chip
Accesses to the expansion bus interface consists of five phases. Each of the five phases
can be lengthened or shortened by setting various configuration registers on a
per-chip-select basis. This feature allows the IXP42X product line and IXC1100 control
plane processors to connect to a wide variety of peripheral devices with varying speeds.
The expansion bus interface supports Intel or Motorola* microprocessor-style bus
cycles. The bus cycles can be configured to be multiplexed address/data cycles or
separate address/data cycles for each of the eight chip-selects.
Additionally, Chip Selects 4 through 7 can be configured to support Texas Instruments
HPI-8 or HPI-16 style accesses for DSPs.
The expansion bus interface is an asynchronous interface to externally connected
chips. However, a clock must be supplied to the IXP42X product line and IXC1100
control plane processors’ expansion bus interface for the interface to operate. This
clock can be driven from GPIO 15 or an external source. The maximum clock rate that
the expansion bus interface can accept is 66.66 MHz.
At the de-assertion of reset, the 24-bit address bus is used to capture configuration
information from the levels that are applied to the pins at this time. External pull-up/
pull-down resistors are used to tie the signals to particular logic levels. For additional
details, refer to Section 8 (Expansion Bus Controller) of the Intel
• Operates at 133.32 MHz (which is 4 * OSC_IN input pin.)
• Supports eight open pages simultaneously
• Has two banks to support memory configurations from 8 Mbyte to 256 Mbyte
IXP42X product line and IXC1100 control plane processors—Datasheet
processor, implementing voice-compression
IXP42X Product Line of Network
Document Number:
IXP42X Product Line
June 2007

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