EP80579 Datasheet, PDF (1412/1916 Pages) Intel Corporation – Intel® EP80579 Integrated Processor Product Line

Intel^® EP80579 Integrated Processor
37.5.11
Serial EEPROM
The GbE controller uses an EEPROM device for storing product configuration
information. The EEPROM is divided into two general regions:
• Hardware accessed - loaded by GbE controller after power-up, Unit Reset
deassertion, D3>D0 transition, or software commanded EEPROM read
(CTRL_EXT.EE_RST).
• Software accessed - used by software only. The meaning of these registers as listed
here is a convention for the software only and is ignored by the controller.
37.5.11.1 EEPROM Device
The EEPROM interface supports a MicroWire* interface. It expects the EEPROM to be
capable of 1MHz operation.
The EP80579 is compatible with a 4096 bit 4-wire serial EEPROM such as is compatible
with a NM93C66 EEPROM. This EEPROM is accessed in 16-bit words, containing 256
words.
The EP80579 will automatically determine whether an EEPROM is connected.
Note:
The EP80579 will ONLY detect presence of the EEPROM during power-up.
37.5.11.2 Software Accesses
The MAC provides two different methods for software access to the EEPROM. It can
either use the built-in controller to read the EEPROM, or access the EEPROM directly
using the EEPROM's 4-wire interface.
Software can use the EEPROM Read register (EERD) to cause the GbE controller to read
a word from the EEPROM that the software can then use. To do this, software writes the
address to read to the Read Address (EERD.ADDR) field and simultaneously writes a 1
to the Start Read bit (EERD.START). The controller will read the word from the
EEPROM, set the Read Done bit (EERD.DONE), and put the data in the Read Data field
(EERD.DATA). Software can poll the EEPROM Read register until it sees the Read Done
bit set, then use the data from the Read Data field. Any words read this way are not
written to internal registers.
Software can also directly access the EEPROM's 4-wire interface through the EEPROM
Control Register (EEC). It can use this for reads, writes, or other EEPROM operations.
To directly access the EEPROM, software should follow these steps:
• Write a 1 to the EEPROM Request bit (EEC.EE_REQ)
• Read the EEPROM Grant bit (EEC.EE_GNT) until it becomes 1. It will remain 0 as
long as the hardware is accessing the EEPROM.
• Write or read the EEPROM using the direct access to the 4-wire interface as defined
in the EEPROM Control & Data Register (EEC). The exact protocol used depends on
the EEPROM placed on the board and can be found in the appropriate datasheet.
• Write a 0 to the EEPROM Request bit (EEC.EE_REQ).
Finally, software can cause the controller to re-read the hardware accessed fields of the
EEPROM (setting the MAC's internal registers appropriately) by writing a 1 to the
EEPROM Reset bit of the Extended Device Control Register (CTRL_EXT.EE_RST).
Note:
This will only cause the EEPROM to be re-read. The Gbe will NOT attempt to re-detect
the presence of an EEPROM.
Intel^® EP80579 Integrated Processor Product Line Datasheet
1412
August 2009
Order Number: 320066-003US