LAN9514 datasheet(32/54 Pages) MICROCHIP

32 / 54 page

LAN9514/LAN9514I

DS00002306A-page 32

 2009-2016 Microchip Technology Inc.

3.2

EEPROM Defaults

The signature value of 0xA5 is stored at address 0. A different signature value indicates to the EEPROM controller that

no EEPROM or an un-programmed EEPROM is attached to the device. In this case, the hardware default values are

used, as shown in Table 3-11.

3.3

EEPROM Auto-Load

Certain system level resets (USB reset, POR, nRESET, and SRST) cause the EEPROM contents to be loaded into the

device. After a reset, the EEPROM controller attempts to read the first byte of data from the EEPROM. If the value 0xA5

is read from the first address, then the EEPROM controller will assume that the external Serial EEPROM is configured

for auto-loading. If a value other than 0xA5 is read from the first address, the EEPROM auto-load will not commence.

Note:

The EEPROM contents are loaded for both the Hub and the Ethernet Controller as a result of a POR or

nRESET. The USB reset results only in the loading of the MAC address from the EEPROM. A software reset

(SRST) or a EEPROM Reload Command causes the EEPROM contents related solely to the Ethernet Con-

troller to be loaded.

3.4

An Example of EEPROM Format Interpretation

Table 3-12 and Table 3-13 provide an example of how the contents of a EEPROM are formatted. Table 3-12 is a dump

of the EEPROM memory (256-byte EEPROM), while Table 3-13 illustrates, byte by byte, how the EEPROM is formatted.

TABLE 3-11:

EEPROM DEFAULTS

Field

Default Value

Ethernet Controller

MAC Address

FFFFFFFFFFFFh

Ethernet Controller

Full-Speed Polling Interval

(mS)

01h

Ethernet Controller

Hi-Speed Polling Interval

(mS)

04h

Ethernet Controller Con-

figuration Flags

05h

Ethernet Controller Maxi-

mum Power (mA)

01h

Ethernet Controller Ven-

dor ID

0424h

Ethernet Controller Prod-

uct ID

EC00h

TABLE 3-12:

DUMP OF EEPROM MEMORY

Offset

Byte

Value

0000h

A5 12 34 56 78 9A BC 01

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