LAN9500 Datasheet, PDF (87/213 Pages) SMSC Corporation – USB 2.0 to 10/100 Ethernet Controller Promiscuous mode

LAN950x
FIGURE 5-27:
EEPROM WRAL CYCLE
EECS
EECLK
EEDIO (OUTPUT)
EEDIO (INPUT)
1
0
0
0
1
tCSL
D7
D0
Table 5-61, "Required EECLK Cycles", shown below, shows the number of EECLK cycles required for each EEPROM
operation.
TABLE 5-61: REQUIRED EECLK CYCLES
Operation
ERASE
ERAL
EWDS
EWEN
READ
WRITE
WRAL
Required EECLK Cycles
10
10
10
10
18
18
18
5.7.4.2 Host Initiated EEPROM Reload
The Host can initiate a reload of the EEPROM by issuing the RELOAD command via the E2P Command (E2P_CMD)
register. If the first byte read from the EEPROM is not 0xA5, it is assumed that the EEPROM is not present, or not pro-
grammed, and the reload will fail. The Data Loaded bit of the E2P_CMD register indicates a successful reload of the
EEPROM.
Note:
It is not recommended that the RELOAD command be used as part of normal operation, as race conditions
can occur with USB Commands that access descriptor data. It is best for the Host to issue a SRST to reload
the EEPROM data.
5.7.4.3 EEPROM Command and Data Registers
Refer to Section 7.3.12, "EEPROM Command Register (E2P_CMD)," on page 136 and Section 7.3.13, "EEPROM Data
Register (E2P_DATA)," on page 139 for a detailed description of these registers. Supported EEPROM operations are
described in these sections.
5.7.4.4 EEPROM Timing
Refer to Section 8.5.4, "EEPROM Timing," on page 198 for detailed EEPROM timing specifications.
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