LAN9730 Datasheet, PDF (86/222 Pages) SMSC Corporation – High-Speed Inter-Chip (HSIC) USB 2.0

LAN9730/LAN9730i
4.7 EEPROM Controller (EPC)
The device may use an external EEPROM to store the default values for the USB descriptors and the MAC address.
The EEPROM controller supports most 256/512 byte “93C46” type EEPROMs.
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 MAC’s ADDRH and ADDRL reg-
isters. 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 EEPROM controller also allows the host system to read, write and erase the contents of the serial EEPROM.
4.7.1 EEPROM FORMAT
Table 4-56 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 ref-
erencing 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 4-56: EEPROM FORMAT
EEPROM Address
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Ah
0Bh
0Ch
0Dh
0Eh
0Fh
10h
11h
12h
13h
14h
15h
EEPROM Contents
0xA5
MAC Address [7:0]
MAC Address [15:8]
MAC Address [23:16]
MAC Address [31:24]
MAC Address [39:32]
MAC Address [47:40]
Full-Speed Polling Interval for Interrupt Endpoint
Hi-Speed Polling Interval for Interrupt Endpoint
Configuration Flags
Language ID Descriptor [7:0]
Language ID Descriptor [15:8]
Manufacturer ID String Descriptor Length (bytes)
Manufacturer ID String Descriptor EEPROM Word Offset
Product Name String Descriptor Length (bytes)
Product Name String Descriptor EEPROM Word Offset
Serial Number String Descriptor Length (bytes)
Serial Number String Descriptor EEPROM Word Offset
Configuration String Descriptor Length (bytes)
Configuration String Descriptor Word Offset
Interface String Descriptor Length (bytes)
Interface String Descriptor Word Offset
DS00001946A-page 86
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