Intel
®
EP80579 Integrated Processor Product Line—Synchronous Peripheral Interface (SPI)
Intel
®
EP80579 Integrated Processor Product Line
Platform Design Guide May 2010
199 Order Number: 320068-005US
16.0 Synchronous Peripheral Interface (SPI)
The EP80579’s Serial Peripheral Interface (SPI) is a 4-pin interface that provides a
potentially lower-cost alternative for system flash versus the Firmware Hub on the LPC
bus. The Serial Peripheral Interface is used to support only one SPI compatible flash
device - only one chip select is available. The SPI flash device can be up to 16 MB
(128 Mbits). The SPI interface operates at 20 MHz clock frequency. See the Intel
®
EP80579 Integrated Processor Product Line Datasheet for additional SPI compatibility
requirements.
16.1 Terminating Unused SPI Port
If the SPI port is not implemented on the system, terminate the signals as follows:
— SPI_MOSI - Leave as no connect (NC)
— SPI_MIS0 - Pull-up with a 10 K-ohm resistor
— SPI_CLK - Leave as no connect (NC)
— SPI_CS# - Leave as no connect (NC)
16.2 SPI Interface General Routing Guidelines
This section contains preliminary information and details for layout and routing
guidelines for the SPI BIOS Flash interface. Also, see the Serial Flash vendor
documentation for additional Serial Flash specific design considerations.
Table 72. Serial Peripheral Interface Signal Description
Group Signal Name Description
Data SPI_MOSI SPI serial output data from EP80579 to SPI flash device
Data SPI_MISO SPI serial input data from the SPI Flash Device to EP80579
Clock SPI_CLK SPI Clock output from EP80579 to SPI Flash Device (20 MHz)
Chip Select SPI_CS#
SPI chip select from EP80579 to SPI Flash Device
Note: If SPI interface is used, pull-up with 10 K-ohm resistor
for signal stabilty during power up.
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