LAN9217 Datasheet, PDF (31/134 Pages) SMSC Corporation – 16-bit High-Performance Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX

16-bit High-Performance Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX
Datasheet
Note: The EEPROM device powers-up in the erase/write disabled state. To modify the contents of
the EEPROM the host must first issue the EWEN command.
If an operation is attempted, and an EEPROM device does not respond within 30mS, the LAN9217
will timeout, and the EPC timeout bit (EPC_TO) in the E2P_CMD register will be set.
Figure 3.2, "EEPROM Access Flow Diagram" illustrates the host accesses required to perform an
EEPROM Read or Write operation.
EEPROM Write
Idle
Write Data
Regis ter
W r ite
Command
Regis ter
Busy Bit = 0
Read
Command
Regis ter
EEPROM Read
Idle
Write
Command
Re gis te r
Read
Command
Re gis te r
Busy Bit = 0
Read Data
Re gis te r
Figure 3.2 EEPROM Access Flow Diagram
The host can disable the EEPROM interface through the GPIO_CFG register. When the interface is
disabled, the EEDIO and ECLK signals can be used as general-purpose outputs, or they may be used
to monitor internal MII signals.
3.10.2.1
Supported EEPROM Operations
The EEPROM controller supports the following EEPROM operations under host control via the
E2P_CMD register. The operations are commonly supported by “93C46” EEPROM devices. A
description and functional timing diagram is provided below for each operation. Please refer to the
E2P_CMD register description in Section 5.3.23, "E2P_CMD – EEPROM Command Register," on
page 95 for E2P_CMD field settings for each command.
ERASE (Erase Location): If erase/write operations are enabled in the EEPROM, this command will
erase the location selected by the EPC Address field (EPC_ADDR). The EPC_TO bit is set if the
EEPROM does not respond within 30ms.
SMSC LAN9217
31
DATASHEET
Revision 1.5 (07-18-06)