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Intel
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IXP43X Product Line of Network Processors—Hardware Design Guidelines
Intel
®
IXP43X Product Line of Network Processors
HDG April 2007
44 Document Number: 316844; Revision: 001US
3.10.1 Signal Interface
3.10.2 Device Connection
There are a number of devices available that can interface to SSP or SPI ports, these
can range from RTC (Real-Time Clock), LCD (Liquid Crystal Displays), Digital Thermal
Sensor to Flash memory devices.
One of the most common usage for SSP or SPI port, is serial flash code storage. Serial
flash devices can be used to store board revision, serial numbers, or assembly
information. Figure 12 provides an example of a Serial Flash device interface to the
SSP port in the IXP43X network processors. For an additional example of SPI interface,
refer to Figure 11, where a SLIC is connected to the SSP and HSS ports.
Table 16. Synchronous Serial Peripheral Port Interface
Name
Type
Field
Pull
Up/
Down
Recommendations
SSP_SCLK O No Serial bit clock.
SSP_SFRM O No Serial frame indicator.
SSP_TXD O No Transmit data (serial data out).
SSP_RXD I Yes
Receive data (serial data in).
Should be pulled high through a 10-KΩ resistor when not being utilized in the system.
SSP_EXTCLK I Yes
External clock input.
Should be pulled high through a 10-KΩ resistor when not being utilized in the system.