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IXP45X and Intel® IXP46X Product Line of Network Process or s
1.0Introduction
This design guide provides recommendations for hardware and system designers who
are developing with the Intel
Processors. This document should be used in conjunction with the Intel
®
Intel
IXP46X Product Line of Network Processors Datasheet and sample schematics
provided for the Intel
®
®
IXP45X and Intel® IXP46X Product Line of Network
IXDP465 Development Platform in that platform’s
documentation kit.
Design Recommendations are necessary to meet the timing and signal quality
specifications.
The guidelines recommended in this document are based on experience and simulation
work done at Intel while developing the Intel
®
IXDP465 Development Platform. These
recommendations are subject to change.
Note:This document discusses all features supported on the Intel
Processor. A subset of these features is supported by certain processors in the IXP45X/
IXP46X product line, such as the Intel® IXP460 or Intel® IXP455 network processors.
For details on feature support listed by processor, see the IntelIXP46X Product Line of Network Processors Datasheet.
1.1Content Overview
Chapter NameDescription
Chapter 1.0, “Introduction”Conventions used in this manual and related documentation
Chapter 2.0, “System Architecture”System architectural block diagram and system memory map
Chapter 3.0, “General Hardware Design
Considerations”
Chapter 4.0, “General PCB Guide”General PCB design practice and layer stack-up description
Chapter 5.0, “General Layout and Routing
Guide”
Chapter 6.0, “PCI Interface Design
Considerations”
Chapter 7.0, “DDR-SDRAM”
Graphical representation of most common peripheral interfaces.
More specific layout and routing recommendations for board
designers
Board-design recommendations when implementing PCI
interface
Board-design recommendations when implementing
DDRI memory interface
®
IXP45X and
®
IXP465 Network
®
IXP45X and Intel®
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Intel® IXP45X and Intel® IXP46X Product Line of Network Processors—Introduction
1.2Related Documentation
The reader of this design guide should also be familiar with the material and concepts
presented in the following documents:
TitleDocument #
Hardware-Assisted IEEE 1588* Implementation in the Intel
Product Line White Paper
®
IXP45X and Intel® IXP46X Product Line of Network Processors
Intel
Developer’s Manual
®
Intel
IXP45X and Intel® IXP46X Product Line of Network Processors
Datasheet
®
IXP4XX Product Line of Network Processors Specification
The IXP45X/IXP46X network processors are highly integrated devices, capable of
interfacing with most common industry standard peripherals, required for highperformance control applications.
Note:This document discusses all features supported on the Intel
Processor. A subset of these features is supported by certain processors in the IXP45X/
IXP46X product line, such as the Intel
®
IXP460 or Intel® IXP455 network processors.
For details on feature support listed by processor, see the IntelIXP46X Product Line of Network Processors Datasheet.
Some of the key features of the IXP45X/IXP46X network processors, when used as a
single-chip solution for embedded applications, are as follows:
•Intel XScale
®
Processor (compliant with Intel® StrongARM* architecture) — Up to
667 MHz
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®
IXP465 Network
®
IXP45X and Intel®
Intel® IXP45X and Intel® IXP46X Product Line of Network Processors—Introduction
• 32-bit PCI interface Master/Target 33/66 MHz
• Device Universal Serial Bus (USB) Controller
• Host Universal Serial Bus (USB) Controller
• DDRI-266 SDRAM (133-MHz Clock, 266-Mbps per data line) — User-enabled ECC,
supports up to 1 Gbyte of external memory
• 32-bit Expansion Bus Interface — Master/Target interface
•Two UART ports
• Up to three Ethernet ports (consult device part number for enabled features) MII/
SMII
• Up to three NPEs
•UTOPIA Level 2 Interface
• Synchronous Serial PortInterface (SSP)
• Two High-Speed Serial Port Interfaces (HSS)
• Inter-Integrated Circuit (IIC or I2C) Interface
• 16 GPIO (General Purpose Input Output)
•Packaging
—544-pin PBGA package
— Commercial temperature (0° to +70° C)
— Extended temperature (-40° to +85° C)
®
For a complete features list and block diagram description, see the Intel
®
Intel
IXP46X Product Line of Network Processors Datasheet.
IXP45X and
Note:Some features require Intel-supplied software. T o determine if a feature is enabled in a
particular software release, refer to the Intel
®
IXP400 Software Specification Update.
A block diagram of all major internal hardware components of the IXP465 network
processor is given in Figure 1. The illustration also shows how the components
interface with each other through the various bus interfaces such as the North AHB,
South AHB, and APB.
®
IXP45X and Intel® IXP46X Product Line of Network Processors
IXP45X and Intel® IXP46X Product Line of Network Processors
2.0System Architecture
2.1System Architecture Description
The Intel® IXP45X and Intel® IXP46X Product Line of Network Processorsare multifunction processors that integrate the Intel XScale
compliant) with highly integrated peripheral controllers and intelligent network
processor engines.
The processor is a highly integrated design, manufactured with Intel’s 0.18-micron
production semiconductor process technology. This process technology — along with
numerous, dedicated-function peripheral interfaces and many features with the Intel
XScale processor — addresses the needs of many system applications and helps reduce
system costs. The processors can be configured to meet many system application and
implementation needs.
Figure 2 illustrates one of many applications for which the IXP45X/IXP46X network
processors can be implemented. For detailed functional descriptions, see the Intel
IXP45X and Intel
®
IXP46X Product Line of Network Processors Developer’s Manual.
2.2System Memory Map
For a complete memory map and register description of each individual module, refer
to the Intel
Developer’s Manual.
®
IXP45X and Intel® IXP46X Product Line of Network Processors
®
Processor (ARM* architecture
®
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Intel® IXP45X and Intel® IXP46X Product Line of Ne twork Processors—System Architecture
Figure 2.Intel® IXP465 Example System Block Diagram
JTAG
Header
Flash
32 Mbyte
Board
Configuration
Reset Logic
CS_N0
D[31:0]
A[24:0]
Ex pansion Bus
®
Intel
IXP46X Product
SDRAM Memory Bus
RAS, CAS, WE, CS,CLK
Line of Network
LCD/LED
Diagnostics
Display
Buff
Processors
DDR
CB[7:0]
D[31:0]
BA[1:0]
A[13:0]
HSS 1
SSPCODEC or
DDR
DDR
SDRAM
SDRAM
SDRAM
16Mx4x16
DDR
16Mx4x16
16Mx4x16
512 Mbyte
SDRAM
512 Mbyte
512 Mbyte
(Four Chips)
Max 1 Gbyt e
(Four Chips)
(Four Chips)
SLIC/CODEC or
T1/E1/J1 FramerHSS 0
A/D
DB9
DB9
RJ45
Port 0
RJ45
Port 2
RS 232
Serial Port 0
RS 232
Serial Port 1
10/100
PHYs
Up to 3Ports
USB Host
Connector
USB Device
Connector
I2C
UTOPIA Level 2
Clock Buff er
3-MII/
3-SMII/
PCI Bus
USB v2.03.3 V
USB v1.1
Transparent PCI Bridge
PCI Slots
Ether net
Clocks
I2C
cPCI Bus
cPCI J2
cPCI J1
2.5 V
1.3 V
xDSL
xDSL
PCI
Clock
Power Supply
xDSL
xDSL
PLL
OSC
B4835 -002
®
IXP45X and Intel® IXP46X Product Line of Network Processors
General Hardware Design Considerations—Intel
Network Processors
®
IXP45X and Intel® IXP46X Product Line of
3.0General Hardware Design Considerations
This chapter contains information for implementing and interfacing to major hardware
blocks of the Intel
®
IXP45X and Intel® IXP46X Product Line of Network Processors.
Such blocks include DDR SDRAM, Flash, SRAM, Ethernet PHYs, UART and most other
peripherals interfaces. Signal definition tables list resistor recommendations for pullups and pull-downs.
Features disabled by a specific part number, do not require pull-ups or pull-downs.
Therefore, all pins can be left unconnected. Features enabled by a specific part number
and required to be Soft Fuse-disabled, only require pull-ups or pull-downs in the clock-input signals. Other conditions may require pull-up or pull-down resistors for
configuration purposes at power on or reset. Likewise, open-collector outputs must be
pulled-high.
Warning:The IXP45X/IXP46X network processors’ I/O pins are 3.3 V only, except for DDR
SDRAM which is 2.5 V. None of the I/Os are 5-V tolerant.
Table 2gives the legend for interpreting the Type field used in this chapter’s signal-
definition tables.
Table 2.Signal Type Definition s
SymbolDescription
IInput pin only
OOutput pin only
I/OPin can be either an input or output
ODOpen-drain pin
TRITri-State pin
PWRPower pin
GNDGround pin
3.1Soft Fusible Features
Soft Fuse Enable/Disable is a method to enable or disable features in hardware,
virtually disconnecting the hardware modules from the processor.
Some of the features offered in the IXP45X/IXP46X product line can be Sof t Fus e
Enabled/Disabled during boot. It is recommended that if a feature is not used in the
design, the feature be Soft disabled. This helps reduce power and maintain the part
running at a cooler temperature. When Soft Fuse Disabled, a pull-up resistor must be
connected to each clock input pins of the disabled feature interface. All other signals
can be left unconnected.
Soft Fuse Enable/Disable can be done by writing to EXP_UNIT_FUSE_RESET register,
for more information refer to the IntelNetwork Processors Developer’s Manual and review the register description.
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®
IXP45X and Intel® IXP46X Product Line of
Intel® IXP45X and Intel® IXP46X Product Line of Network Processors
Intel® IXP45X and Intel® IXP46X Product Line of Network Processors—General Hardware
Table 3.Soft Fusible Features
NameDescription
PCIThe complete bus must be enabled or disable.
HSS0/1Can only be disable as a pair.
UTOPIA
ETHERNET
USB HostEach USB can be Enable separately.
USB DeviceEach USB can be Enable separately.
DDR ECCDDR can be disabled separately form the rest of the DDR interface.
If enabling UTOPIA, MACs on NPE A are disabled.
If enabling MACs on NPE A, UTOPIA are disabled.
Can Enable either MII MACs or SMII MACs, but not both at the same time. Enable of MACs
can be separately done per each NPE.
3.2DDR-266 SDRAM Interface
The IXP45X/IXP46X network processors support unbuffered, DDR-266 SDRAM
technology, capable of addressing two memory banks (one bank per CS). Each bank
can be configured to support 32/64/128/256/512-Mbyte for a total combined memory
support of 1 Gbyte.
Design Considerations
The device supports non-ECC and ECC for error correction, which can be enable or
disable by software as required. Banks have a bus width of 32 bits for non ECC or
40 bits for ECC enable (32-bit data + 8-bit ECC).
For a complete feature list, see the Intel
®
IXP45X and Intel® IXP46X Product Line of
Network Processors Datasheet.
General DDR SDRAM routing guidelines can be found in Section 7.1.7, “Routing
Guidelines” on page 88. For more detailed information, see the PC266 DDR SDRAM
specification.
3.2.1Signal Interface
Table 4.DDR SDRAM Interface Pin Description (Sheet 1 of 2)
Name
DDRI_CK[2:0]O
DDRI_CK_N[2:0]OSame as aboveNo
DDRI_CS_N[1:0]O
DDRI_RAS_NO
DDRI_CAS_NO
Input
Outpu
t
Device-Pin Connection
Connect a pair of differential clock
signals to every device; When
using both banks, daisy chain
devices with same data bit
sequence.
Use the same CS to control 32-bi t
data + 8-bit ECC, per bank
The RAS signal must be connected
to each device in a daisy chain
manner
The CAS signal must be connected
to each device in a daisy chain
manner
VTT
Terminatio
n
No
Yes
Yes
Yes
DDR SDRAM Clock Out — Provides the positive
differential clocks to the external SDRAM
memory subsystem.
DDR SDRAM Clock Out — Provides the
negative differential clocks to the external
SDRAM memory subsystem.
Chip Select — Must be asserted for all
transactions to the DDR SDRAM device. One
per bank.
Row Address Strobe — Indicates that the
current address on DDRI_MA[13:0] is the row.
Column Address Strobe — Indicates that the
current address on DDRI_MA[13:0] is the
column.
Description
®
IXP45X and Intel® IXP46X Product Line of Network Processors
General Hardware Design Considerations—Intel
Network Processors
®
IXP45X and Intel® IXP46X Product Line of
Table 4.DDR SDRAM Interface Pin Description (Sheet 2 of 2)
Name
DDRI_WE_NO
DDRI_DM[4:0]O
DDRI_BA[1:0]O
DDRI_MA[13:0]O
DDRI_DQ[31:0]I/O
DDRI_CB[7:0]I/OConnect to ECC memory devices.Yes
DDRI_DQS[4:0]I/O
DDRI_CKE[1:0]O
DDRI_RCVENOUT_NO
DDRI_RCVENIN_NISame as aboveNo
DDRI_RCOMPOTied off to a resistor
DDRI_VREFIVCCM/2VCCM/2
Input
Outpu
t
Device-Pin Connection
The WE signal must be connected
to each device in a daisy chain
manner
Connect to each DM device pin.
For the 8-bit devices connect one
DM signal per device.
For the 16-bit devices connect two
DM signal per device (depending
on how many data bits are being
used).
The BA signals must be connected
to each device in a daisy chain
manner.
All address signals need to be
connected to each device in a
daisy chain manner.
Need to be connected in parallel
to achieve a 32-bit bus width.
Connect DQS[3:0] to devices wi th
data signals and DQS[4] to
devices with ECC signals.
Use one CKE per bank, never mix
the CKE on the same bank. Use
CKE[0] for bank0 and CKE[1] for
bank1
Connect RCVEOUT to RCVENIN
and follow note on pin description
in this table.
VTT
Terminatio
n
Yes
Yes
Yes
Yes
YesData Bus — 32-bit wide data bus.
Yes
Yes
No
Tied off to a
resistor
Description
Write Strobe — Defines whether or not the
current operation by the DDR SDRAM is to be
a read or a write.
Data Bus Mask — Controls the DDR SDRAM
data input buffers. Asserting DDRI_WE_N
causes the data on DDRI_DQ[31:0] and
DDRI_CB[7:0] to be written into the DDR
SDRAM devices.
DDRI_DM[4:0] controls this operation on a
per-byte basis. DDRI_DM[3:0] are intended to
correspond to each byte of a word of data.
DDRI_DM[4] is intended to be utilized for the
ECC byte of data.
DDR SDRAM Bank Selects — Controls which of
the internal DDR SDRAM banks to read or
write. DDRI_BA[1:0] are used for all
technology types supported.
Address bits 13 through 0 — Indicates the row
or column to access depending on the state of
DDRI_RAS_N and DDRI_CAS_N.
ECC Bus — Eight-bit error correction code
which accompanies the data on
DDRI_DQ[31:0].
When ECC is disabled and not being used in a
system design, these signals can be left unconnected.
Data Strobes Differential — Strobes that
accompany the data to be read or written from
the DDR SDRAM devices. Data is sampled on
the negative and positive edges of these
strobes. DDRI_DQS[3:0] are intended to
correspond to each byte of a word of data.
DDRI_DQS4] is intended to be utilized for the
ECC byte of data.
Clock enables — One clock after
DDRI_CKE[1:0] is de-asserted, data is latched
on DQ[31:0] and DDRI_CB[7:0]. Burst
counters within DDR SDRAM device are not
incremented. De-asserting this signal places
the DDR SDRAM in self-refresh mode. For
normal operation, DDRI_CKE[1:0] must be
asserted.
RECEIVE ENABLE OUT must be connected to
DDRI_RCVENIN_N signal of the IXP45X/
IXP46X product line and the propagation delay
of the trace length must be matched to the
clock trace plus the average DQ Traces.
RECEIVE ENABLE IN provides delay
information for enabling the input receivers
and must be connected to the
DDRI_RCVENOUT_N signal
IXP46X network processors.
20 Ohm Resistor connected to ground used for
process/temperature adjustments.
DDR SDRAM Voltage Reference — is used to
supply the reference voltage to the di fferential
inputs of the memory controller pins.
of the IXP45X/
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Intel® IXP45X and Intel® IXP46X Product Line of Network Processors—General Hardware
3.2.2DDR SDRAM Memory Interface
The IXP45X/IXP46X network processors support compatible DDR-266 SDRAM, 8- and
16-bit wide devices, with a total bus width of 32 bits. Only 32-bit-wide accesses are
supported.
The maximum supported memory is 1 Gbyte, configured by enabling both physical
banks of DDR-266 SDRAM devices. Each bank can be composed of four 1-Gbit (32 Mbit
X 8 X 4) devices and use one chip-selects per bank. The minimum supported memory
is 32 Mbyte, configured by enabling a single physical bank of DDR-266 SDRAM devices.
The bank would consist of two 128-Mbit (2 Mbit X 16 X 4) devices and using a single
chip-select.
All supported memory configurations are listed in T able 28 on page 78. Remember that
these are all non-buffer devices, as the IXP45X/IXP46X network processors only
support non-buffer memory devices.
For a complete description on how the IXP45X/IXP46X network processors interface to
DDR SDRAM, see Chapter 7.0, “DDR-SDRAM”.
3.2.3DDR SDRAM Initialization
For instructions on DDR SDRAM initialization, refer to the Intel® IXP45X and Intel®
IXP46X Product Line of Network Processors Developer’s Manual and its section titled
“DDR SDRAM Initialization.”
Design Considerations
3.3Expansion Bus
The Expansion Bus of the IXP45X/IXP46X network processors is specifically designed
for compatibility with Intel- and Motorola*-style microprocessor interfaces and Texas
Instruments* DSP standard Host-Port Interfaces* (HPI).
The expansion bus controller includes a 25-bit address bus and a 32-bit wide data path,
running at a maximum speed of 80 MHz from an external clock oscillator. The bus can
be configure to support the following target devices:
• Intel multiplexed• Intel non-multiplexed
•Intel StrataFlash
• Micron* Flow-Through ZBT• Motorola multiplexed
• Motorola non multiplexed• Texas Instruments* Host Port Interface
The expansion bus controller also has an arbiter that supports up to four external
devices that can master the expansion bus. External masters can be used to access
external slave devices that reside on the expansion bus, including access to internal
memory mapped regions within the IXP45X/IXP46X network processors.
All supported modes are seamless and no additional glue logic is required. Other cycle
types may be supported by configuring the Timing and Control Register for Chip Select.
Applications having less than 32 data bits may connect to less than the full 32 bits.
Devices with wider than 32-bit data bus are not supported. A total of eight chip selects
are supported with an address space of up to 32 Mbytes per chip select.
®
• Synchronous Intel StrataFlash
®
Memory
(HPI)
®
IXP45X and Intel® IXP46X Product Line of Network Processors
General Hardware Design Considerations—Intel
Network Processors
®
IXP45X and Intel® IXP46X Product Line of
3.3.1Signal Interface
Table 5.Expansion Bus Signal Recommendations
Name
EX_CLKINoUse series termination resistor, 10Ω to 33Ω at the source.
EX_ALETRI ONoUse series termination resistor, 10Ω to 33Ω at the source.
EX_ADDR[24:0]I/OYes
EX_WR_NI/ONoUse series termination resistor, 10Ω to 33Ω at the source.
EX_RD_NI/ONoUse series termination resistor, 10Ω to 33Ω at the source.
EX_CS_N[7:0]I/OYes
EX_DATA[31:0]I/ONo
EX_BE_N[3:0]I/ONo
EX_IOWAIT_NIYesShould be pulled high through a 10-KΩ resistor when not being utilized in the system.
EX_RDY_N[3:0]IYesShould be pulled high through a 10-KΩ resistor when not being utilized in the system.
EX_PARITY[3:0]I/ONo
EX_REQ_N[3:1]IYesShould be pulled high through a 10-KΩ resistor when not being utilized in the system.
EX_REQ_GNT_NIYesShould be pulled high through a 10-KΩ resistor when not being utilized in the system.
EX_GNT_N[3:1]ONo
EX_GNT_REQ_NONo
EX_SLAVE_CS_NIYesShould be pulled high through a 10-KΩ resistor when not being utilized in the system.
EX_BURSTIYesShould be pulled high through a 10-KΩ resistor when not being utilized in the system.
EX_WAIT_NTRI ONo
Input
Output
Pull
Up
Down
Use 4.7-KΩ resistors for pull-downs; required for boot strapping for initial configuration of
Configuration Register 0. Pull-ups are not required as for when the system comes out of
reset, all bits are initially set HIGH. For more details, see Table 6.
For additional details on address strapping, see the IntelProduct Line of Network Processors Developer’s Manual.
Use series termination resistor, 10Ω to 33Ω at the source.
Use 10KΩ resistors pull-ups to ensure that the signal remains de-asserted.
Recommendations
®
IXP45X and Intel® IXP46X
3.3.2Reset Configuration Straps
At power up or whenever RESET_IN_N is asserted, the Expansion-bus address outputs
are switched to inputs and the state of the inputs are captured and stored in
Configuration Register 0, bits 24 through 0. This occurs when PLL_LOCKED is deasserted.
The strapping of Expansion-bus address pins can be done by placing external pull-down
resistors at the required address pin. It is not required to use external pull-up resistors,
by default upon reset all bits on Configuration Register 0 are set High, unless an
external pull down is used to set them Low. For example to register a bit low or high in
the Configuration Register 0, do the following:
Place an external 4.7-KΩ pull-down resistor to set a bit LOW.
No external pull-up is required, by default upon reset, bits are set HIGH.
The state of the boot-strapping resistor is register on the first cycle after the
synchronous de-assertion of the reset signal. These bits can be read or written as
needed for desired configurations. It is recommended that only Bit 31, Memory Map, be
changed from 1 to 0 after execution of boot code from external flash.
February 2007HDD
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Intel® IXP45X and Intel® IXP46X Product Line of Network Processors
Intel® IXP45X and Intel® IXP46X Product Line of Network Processors—General Hardware
For a complete bit description of Configuration Register 0, see the Intel® IXP45X and
®
Intel
IXP46X Product Line of Network Processors Developer’s Manual.
Design Considerations
Table 6.Boot/Reset Strapping Configuration (Sheet 1 of 2)
NameFunctionDescription
EX_ADDR[24](Reserved)(Reserved)
Intel XScale
EX_ADDR[23:21]
EX_ADDR[20:17]CustomerCustomer-defined bits. (Might be used for board revision.)
EX_ADDR[16:11](Reserved)(Reserved)
EX_ADDR[10]IOWAIT_CS0
EX_ADDR[9]EXP_MEM_DRIVERefer to table found in EX_ADDR[5].
EX_ADDR[8]USB Clock
EX_ADDR[7]32_FLASHRefer to table found in EX_ADDR[0]
EX_ADDR[6]EXP_ARB
EX_ADDR[5]EXP_DRIVE
EX_ADDR[4]PCI_CLK
EX_ADDR[3](Reserved)(Reserved). EX_ADDR[3] must not be pulled down during address strapping.
Processor
Clock Set[2:0]
®
Allows changing Intel XScale
settings. However cannot be used to over-clock core speed.
1 = EX_IOWAIT_N is sampled during the read/write expansion bus cycles for Chip
Select 0.
0 = EX_IOWAIT_N is ignored for read and write cycles to Chip select 0 if
EXP_TIMING_CS0 is configured to Intel mode.
Typically, IOWAIT_CS0 must be pulled down to Vss when attaching a Synchronous
Intel StrataFlash
Intel mode and EX_IOWAIT_N is an unknown value for Synchronous Intel
StrataFlash.
If the board does not connect the Synchronous Intel StrataFlash WAIT pin to
EX_WAIT_N (and the board guarantees EX_IOWAIT_N is pulled up), the value of
IOWAIT_CS0 is a don’t-care, since EX_IOWAIT_N will not be asserted.
When EXP_TIMING_CS0 is reconfigure to Intel Synchronous mode during boot-up
(for synchronous Intel chips), the expansion bus controller ignores EX_IOWAIT_N
during read and write cycles since the WAIT functionality is determined from the
EXP_SYNCINTEL_COUNT and EXP_TIMING_CS registers.
Controls the USB clock select.
1 = USB Host/Device clock is generated internally
0 = USB Device clock is generated from GPIO[0].
USB Host clock is generated from GPIO[1]. When generating a spread spectrum
clock on OSC_IN, GPIO[0] can be driven from the system board to generate a
48-MHz clock for the USB Device and GPIO[1] can be driven from the system board
to generate a 60-MHz clock for the USB Host.
Configures the Expansion bus arbiter.
0 = External arbiter for Expansion bus.
1 = Expansion bus controller arbiter enabled
Expansion bus low/medium/high drive strength. The drive strength depends on
EXP_DRIVE and EXP_MEM_DRIVE configuration bits.
The IXP45X/IXP46X network processors support 8-bit-wide data bus devices (byte
mode). For Intel interface cycles, the data lines and control signals can be connected as
shown in Figure 3 on page 25 and Figure 4 on page 26. During byte mode accesses,
the remaining data signals not being used EX_DAT A[31:8], are driven by the processor
to an unpredictable state on WRITE cycles and tri-stated during READ cycles.
When booting an 8-bit flash device, the expansion bus must be configured during reset
to the 8-bit mode (see Configuration Register 0). To accomplish this, boot-strapping is
required in certain address pins of the Expansion bus. For example, as in this case
when booting of an 8-bit flash device, bit 0 and 7 of Configuration Register 0 must be
set as follows:
Bit 0 = 1. By default this bit is set high when coming off reset or any time reset is
asserted.
Bit 7 = 0. This can be done by placing an external 4.7-KΩ pull-down resistor to pin
EX_ADDR[7].
If it is required to change access mode, after the system has booted, and during
normal operation; the Timing and Control Register for Chip Select must be configured
to perform the desired mode access. For a complete description on accomplishing this
refer to the “Expansion Bus” chapter in the IntelLine of Network Processors Developer’s Manual.
3.3.416-Bit Device Interface
The IXP45X/IXP46X network processors support 16-bit wide data bus devices (16-bit
word mode). For Intel interface cycles, the data lines and control signals can be
connected as shown in Figure 3 on page 25 and Figure 4 on page 26. During word
mode accesses, the remaining data signals not being used EX_DAT A[31:16], are driven
by the processor to an unpredictable state on WRITE cycles and tri-stated during READ
cycles.
When booting a 16-bit flash device, the expansion bus must be configured during reset
to the 16-bit mode (see Configuration Register 0). To accomplish this, boot-strapping is
required in certain address pins of the Expansion bus.
®
IXP45X and Intel® IXP46X Product
February 2007HDD
Document Number: 305261; Revision: 00423
Intel® IXP45X and Intel® IXP46X Product Line of Network Processors
Intel® IXP45X and Intel® IXP46X Product Line of Network Processors—General Hardware
For example, as in this case when booting of a 16-bit flash device, bit 0 and 7 of
Configuration Register 0 must be set as follows:
• Bit 0 = 0.
This can be done by placing an external 4.7-KΩ pull-down resistor to pin
EX_ADDR[0].
• Bit 7 = 0.
This can be done by placing an external 4.7-KΩ pull-down resistor to pin
EX_ADDR[7].
If it is required to change access mode, after the system has booted, and during
normal operation; the Timing and Control Register for Chip Select must be configured
to perform the desired mode access. For a complete description on accomplishing this
refer to the “Expansion Bus” chapter in the IntelLine of Network Processors Developer’s Manual.
3.3.532-Bit Device Interface
The IXP45X/IXP46X network processors support 32-bit wide data bus devices (32-bit
word mode). For Intel interface cycles, the data lines and control signals can be
connected as shown in Figure 3 on page 25 and Figure 4 on page 26.
When booting a 32-bit flash device, the expansion bus must be configured during reset
to the 32-bit mode (see Configuration Register 0). To accomplish this, boot-strapping is
required in certain address pins of the Expansion bus. For example, as in this case
when booting of a 32-bit flash device, bit 0 and 7 of Configuration Register 0 must be
set as follows:
• Bit 0 = 1.
By default this bit is set high when coming off reset or any time reset is asserted.
• Bit 7 = 1.
By default this bit is set high when coming off reset or any time reset is asserted.
Design Considerations
®
IXP45X and Intel® IXP46X Product
If it is required to change access mode, after the system has booted, and during
normal operation; the Timing and Control Register for Chip Select must be configured
to perform the desired mode access. For a complete description on accomplishing this
refer to the “Expansion Bus” chapter in the Intel
®
IXP45X and Intel® IXP46X Product
Line of Network Processors Developer’s Manual.
®
IXP45X and Intel® IXP46X Product Line of Network Processors
General Hardware Design Considerations—Intel
Network Processors
3.3.6Flash Interface
®
IXP45X and Intel® IXP46X Product Line of
Figure 5 illustrates how a boot ROM is connected to the expansion bus. The flash (ROM)
used in the block diagram is the Intel StrataFlash
32-Mbyte, 16-bit, flash in the 56-TSOP package. The Intel StrataFlash memory
TE28F256J3D is part of the 0.13-micron, 3.3-V Intel StrataFlash memory.
The E28F256J3D supports common flash interface (CFI). For information on migrating
from J3 to J3D Intel StrataFlash memory, see the Intel StrataFlash
(document 308555).
For information on migrating from J3 to P30 Intel StrataFlash memory, see the
Migration Guide for Intel StrataFlash
Memory (P30 and P33) - Application Note 835 (document 308555).
The example in Figure 5 shows a 16-bit flash memory device connected to the IXP45X/
IXP46X network processors. Boot-strapping is required in the address bus, both
EX_ADDR[0] and EX_ADDR[7] need external, 4.7-KΩ pull-down resistors (not shown
on diagram). The pull-down resistors sets Bits 0 and 7 low in the Configuration Register
0. This in turn sets the processor into a 16-bit-mode access.
Figure 5.Flash Interface Example
EX_DAT A[31:0]
Intel® IXP46X
Product Line of
Netw or k Pro cessor s
EX_ADDR[24:0]
®
Memory (J3) to Intel StrataFlash® Embedded
EX_DAT A[15:0]
2
[
X
E
_
4
R
D
:
D
A
®
memory device TE28F256J3D —
®
Memory J3 to
DATA[15:0]
16-Bit Device
16 -Bi t-Wo rd Access
0
]
ADDR[24:0]
EX_CS_N
EX_RD_N
EX_WR_N
4.7 KΩ4.7 KΩ
CS
OE
WR
3.3 V
RST#
CE0
OE_N
WR_N
Intel® Flash
RP_N
CE1
CE2
BYTE_N
VPEN_N
4. 7 KΩ
B4097- 003
February 2007HDD
Document Number: 305261; Revision: 00427
Intel® IXP45X and Intel® IXP46X Product Line of Network Processors
Intel® IXP45X and Intel® IXP46X Product Line of Network Processors—General Hardware
3.3.7SRAM Interface
A typical connection between an 8-bit SRAM memory device and the IXP45X/IXP46X
network processors expansion bus is shown in Figure 6 on page 28. When attempting
to communicate to this device, the Timing and Control Register for Chip Select must be
configured for proper access. For more information, see the Intel
.
Figure 6.Expansion Bus SRAM Interface
IXP46X Product Line of Network Processors Developer’s Manual.
Design Considerations
®
IXP45X and Intel®
Intel® IXP46X
Product Line of
N etwo rk Pro cesso rs
3.3.8Design Notes
Care must be taken when loading the bus with too many devices. As more devices are
added, the loading capacity adds up — to the point where timing can become critical.
To account for this, timing on the expansion bus may be adjusted in the Timing and
Control Register for Chip Select. If an edge rises slowly due to low drive strength, the
processors should wait an extra cycle before the value is read. For more information,
see the documentation on Timing and Control Register for Chip Select bits [29:16] in
the Intel
Manual.
®
IXP45X and Intel® IXP46X Product Line of Network Processors Developer’s
EX_DATA[31:0]
EX_ADDR[24:0]
EX_CS_N
EX_RD_N
EX_WR_N
EX_DATA[7:0]
EX_ADDR[18:0]
CS
OE
WR
DATA[7:0]
8-Bit Device
Byte Access
ADDR[18:0]
E#
G#
W#
512 Kbyte-x-8
SRAM
Inte rfa ce
B 4098-003
3.4UART Interface
The IXP45X/IXP46X network processors provide two dedicated, Universal
Asynchronous Receiver/Transmitter Serial Ports (UARTs). These are high-speed UART s,
capable of supporting baud rates from 1,200 Baud to 921.6 KBaud.
The hardware supports a four-wire interface:
• Transmit Data
• Receive Data
•Request to Send
•Clear to Send
®
IXP45X and Intel® IXP46X Product Line of Network Processors
General Hardware Design Considerations—Intel
Network Processors
®
IXP45X and Intel® IXP46X Product Line of
Note:The UART module does not support full modem functionality. However, this can be
implemented, by using GPIO ports to generate DTR, DSR, RI, and DCD and making
some changes to the driver.
3.4.1Signal Interface
Table 7.UART Signal Recommendations
Name
RXDATA0IYes
TXDATA0ONoSerial data output Port 0.
CTS0_NIYes
RTS0_NONoRequest-To-Send Port 0.
RXDATA1IYes
TXDATA1ONoSerial data output Port 1.
CTS1_NIYes
RTS1_NONoRequest-To-Send Port 1.
Input
Output
Pull
Up
Down
Serial data input Port 0.
When signal is not being used in the system, this pin should be pulled high with a 10-KΩ
resistor.
Clear-To-Send Port 0.
\When signal is not being used in the system, this pin should be pulled high with a 10-KΩ
resistor.
Serial data input Port 1.
When signal is not being used in the system, this pin should be pulled high with a 10-KΩ
resistor.
Clear-To-Send Port 1.
When signal is not being used in the system, this pin should be pulled high with a 10-KΩ
resistor.
The following figure contain a typical four signal interface between the UART and an
RS-232 transceiver driver, required to interface with external devices. Unused inputs to
the RS-232 driver can be connected to ground. This avoids signals floating to
undetermined states which can cause over heating of the driver leading to permanent
damage.
Recommendations
February 2007HDD
Document Number: 305261; Revision: 00429
Intel® IXP45X and Intel® IXP46X Product Line of Network Processors
Intel® IXP45X and Intel® IXP46X Product Line of Network Processors—General Hardware
Figure 7.UART Interface Example
CTS1_N
RTS1_N
UART
Interface
RXDATA1
TXDATA1
Intel® IXP46X
Intel® IXP46X
Product Line of
Product Line of
Netw or k P r ocesso r s
N etwo rk Pro cesso rs
OUT4
IN3
OUT3
OUT1
OUT2
IN2
RS-232
Transceiver
IN1
IN4
NC
DB9
Con nector
6
7
8
9
Design Considerations
1 DC D
1
2 RX
3 TX
2
4 DTR
3
5 GND
6 DSR
4
7 RTS
8 CTS
5
9 RI
3.5MII/SMII Interface
The IXP45X/IXP46X network processors support a maximum of three Ethernet MACs.
Depending on the IXP45X/IXP46X network processors part number used, various
combinations can be used. For the various features that can be enable a variety of
needs, see the IntelDatasheet.
All MACs contained in the NPEs are compliant to the IEEE 802.3 specification and
handle flow control for the IEEE 802.3Q VLAN specification.
The Management Data Interface (MDI) supports a maximum of 32 PHY addresses. MDI
signals are required to be connected to every PHY chip. Each PHY port is assign a
unique address in the external PHY chip from 0 to 31, totaling a maximum of 32 PHY
addresses. The maximum number of MACs supported by the IXP45X/IXP46X network
processors is three.
The MII interface supports clock rates of 25 MHz for 100-Mbps operation or 2.5 MHz for
10-Mbps operation.
SMII interface supports clock rate of 125 MHz for 10/100-Mbps operation.
General PHY Ethernet devices routing guidelines can be found in Section 5.2.3, “SMII
Signal Considerations” on page 67. For more detailed information, see the IEEE 802.3
specification.
®
IXP45X and Intel® IXP46X Product Line of Network Processors
B4099 -003
®
IXP45X and Intel® IXP46X Product Line of Network Processors