LAN7500 datasheet(19/58 Pages) MICROCHIP

19 / 58 page

Hi-Speed USB 2.0 to 10/100/1000 Ethernet Controller

Datasheet

 2014 Microchip Technology Inc.

DS00001734A-page 19

Chapter 3 EEPROM Controller (EPC)

LAN7500/LAN7500i may use an external EEPROM to store the default values for the USB descriptors

and the MAC address. The EEPROM controller supports most “93C56 or 93C66” type 256/512 byte

EEPROMs. A total of nine address bits are used for connection to the device.

Note: A 3-wire style 2K/4K EEPROM that is organized for 256/512 x 8-bit operation must be used.

The MAC address is used as the default Ethernet MAC address and is loaded into the device’s MAC

address registers. If a properly configured EEPROM is not detected, it is the responsibility of the Host

LAN Driver to set the IEEE addresses.

After a system-level reset occurs, the device will load the default values from a properly configured

EEPROM. The device will not accept USB transactions from the Host until this process is completed.

The device’s EEPROM controller also allows the Host system to read, write and erase the contents of

the Serial EEPROM.

3.1

EEPROM Format

Table 3.1 illustrates the format in which data is stored inside of the EEPROM.

Note the EEPROM offsets are given in units of 16-bit word offsets. A length field with a value of zero

indicates that the field does not exist in the EEPROM. The device will use the field’s HW default value

in this case.

Note: For the device descriptor, the only valid values for the length are 0 and 18.

Note: For the configuration and interface descriptor, the only valid values for the length are 0 and 18.

Note: The EEPROM programmer must ensure that if a string descriptor does not exist in the

EEPROM, the referencing descriptor must contain 00h for the respective string index field.

Note: If all string descriptor lengths are zero, then a Language ID will not be supported.

Table 3.1 EEPROM Format

EEPROM ADDRESS

EEPROM CONTENTS

00h

A5h (EEPROM Programmed Indicator)

01h

MAC Address [7:0]

02h

MAC Address [15:8]

03h

MAC Address [23:16]

04h

MAC Address [31:24]

05h

MAC Address [39:32]

06h

MAC Address [47:40]

07h

Full-Speed Polling Interval for Interrupt Endpoint

08h

Hi-Speed Polling Interval for Interrupt Endpoint

09h

Configuration Flags 0

0Ah

Language ID Descriptor [7:0]

LAN7500 Datasheet(PDF) 19 Page - Microchip Technology

LAN7500 Datasheet(HTML) 19 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58

Datasheet Download

Link URL