Datasheet

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 Ta ble 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 Ta ble 3- 1 3 provide an example of how the contents of a EEPROM are formatted. Tab le 3- 1 2 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