SMSC LAN9420, LAN9420i EECS, Note:, EECLK, EEDIO (INPUT), EEDIO (OUTPUT), EWEN (Erase/Write Enable):, EWDS (Erase/Write Disable):, Figure 3.10 EEPROM EWDS Cycle

Single-Chip Ethernet Controller with HP Auto-MDIX Support and PCI Interface

Datasheet

EWDS (Erase/Write Disable): After issued, the EEPROM will ignore erase and write commands. To re-enable erase/write operations issue the EWEN command.

tCSL

EECS

EECLK

EEDIO (OUTPUT) 1 0 0 0 0

EEDIO (INPUT)

Figure 3.10 EEPROM EWDS Cycle

EWEN (Erase/Write Enable): Enables the EEPROM for erase and write operations. The EEPROM will allow erase and write operations until the “Erase/Write Disable” command is sent, or until power is cycled.

Note: The EEPROM device will power-up in the erase/write-disabled state. Any erase or write operations will fail until an Erase/Write Enable command is issued.

tCSL

EECSEECLK

EEDIO (OUTPUT) 1 0 0 1 1

EEDIO (INPUT)Figure 3.11 EEPROM EWEN Cycle

SMSC LAN9420/LAN9420i	35	Revision 1.22 (09-25-08)
	DATASHEET