High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface

Datasheet

BITS

 

DESCRIPTION

 

TYPE

DEFAULT

 

 

 

 

 

 

 

 

30:28 EEPROM Controller Command (EPC_COMMAND)

 

R/W

000b

This field is used to issue commands to the EEPROM controller. The

 

EEPROM controller will execute a command when the EPC_BUSY bit is set.

 

A new command must not be issued until the previous command completes.

 

The field is encoded as follows:

 

 

 

 

 

 

 

 

 

 

 

[30]

[29]

[28]

 

Operation

 

 

 

 

 

 

 

 

 

 

 

0

0

0

 

READ

 

 

 

 

 

 

 

 

 

 

 

0

0

1

 

EWDS

 

 

 

 

 

 

 

 

 

 

 

0

1

0

 

EWEN

 

 

 

 

 

 

 

 

 

 

 

0

1

1

 

WRITE

 

 

 

 

 

 

 

 

 

 

 

1

0

0

 

WRAL

 

 

 

 

 

 

 

 

 

 

 

1

0

1

 

ERASE

 

 

 

 

 

 

 

 

 

 

 

1

1

0

 

ERAL

 

 

 

 

 

 

 

 

 

 

 

1

1

1

 

RELOAD

 

 

 

 

 

 

 

 

 

 

Note: Only the READ, WRITE and RELOAD commands are valid for I2C mode. If an unsupported command is attempted, the EPC_BUSY bit will be cleared and EPC_TIMEOUT will be set.

The EEPROM operations are defined as follows:

READ (Read Location)

This command will cause a read of the EEPROM location pointed to by the

EPC_ADDRESS bit field. The result of the read is available in the EEPROM Data

Register (E2P_DATA).

EWDS (Erase/Write Disable)

(Microwire mode only) - When this command is issued, the EEPROM will ignore erase and write commands. To re-enable erase/writes operations, issue the EWEN command.

EWEN (Erase/Write Enable)

(Microwire mode only) - Enables the EEPROM for erase and write operations. The EEPROM will allow erase and write operations until the EWDS command is sent, or until the power is cycled. The Microwire EEPROM device will power-up in the erase/write disabled state. Any erase or write operations will fail until an EWEN command is issued.

WRITE (Write Location)

If erase/write operations are enabled in the EEPROM, this command will cause the contents of the EEPROM Data Register (E2P_DATA) to be written to the EEPROM location selected by the EPC_ADDRESS field. For Microwire, erase/write operations must be enabled in the EEPROM.

WRAL (Write All)

(Microwire mode only) - If erase/write operations are enabled in the EEPROM, this command will cause the contents of the EEPROM Data Register (E2P_DATA) to be written to every EEPROM memory location.

ERASE (Erase Location)

(Microwire mode only) - If erase/write operations are enabled in the EEPROM, this command will erase the location selected by the EPC_ADDRESS field.

ERAL (Erase All)

(Microwire mode only) - If erase/write operations are enabled in the EEPROM, this command will initiate a bulk erase of the entire EEPROM.

RELOAD (EEPROM Loader Reload)

Instructs the EEPROM Loader to reload the device from the EEPROM. If a value of A5h is not found in the first address of the EEPROM, the EEPROM is assumed to be un-programmed and the RELOAD operation will fail. The CFG_LOADED bit indicates a successful load. Following this command, the device will enter the not ready state. The READY bit in the Hardware Configuration Register (HW_CFG) should be polled to determine then the RELOAD is complete.

27:19 RESERVED

RO

-

Revision 1.4 (08-19-08)

198

SMSC LAN9312

 

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