General Hardware Design Considerations—Intel®IXP45X and Intel® IXP46X Product Line of Network Processors

3.11.1Signal Interface

Table 19.

Synchronous Serial Peripheral Port Interface

 

 

 

 

 

Input/

Pull

 

Name

Up/

Recommendations

Output

 

Down

 

 

 

 

 

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-KΩresistor when not being utilized in the system.

 

 

 

 

 

 

 

SSP_EXTCLK

I

Yes

External clock input.

Should be pulled high through a 10-KΩresistor when not being utilized in the system.

 

 

 

 

 

 

 

3.11.2Device 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 15 provides an example of a Serial Flash device interface to the SSP port in the IXP45X/IXP46X network processors. For an additional example of SPI interface, refer to Figure 14, in which a SLIC is connected to the SSP and HSS ports.

Figure 15. Serial Flash and SSP Port (SPI) Interface Example

Intel® IXP46X

 

Product Line

 

Network Processors

SPI Flash

SSP_SCLK

 

 

 

CLK

 

 

SSP_SFRM

 

 

 

CS_N

 

 

SSP_TXD

 

 

 

 

 

D I

 

 

 

SSP_RXD

 

DO

 

 

 

 

 

 

 

 

SSP_EXTCLK

7.2 KHz to 3.6864 MHz

SSP Interface

External Oscillator

B4109-001

 

Intel® IXP45X and Intel® IXP46X Product Line of Network Processors

February 2007

HDD

Document Number: 305261; Revision: 004

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Intel IXP45X, IXP46X manual Synchronous Serial Peripheral Port Interface