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]
0
[29]
0
[28]
0
Operation
READ
0
0
1
EWDS
0
1
0
EWEN
WRITE
WRAL
0
1
1
1
0
0
1
0
1
ERASE
ERAL
1
1
0
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 1.2 (04-08-08)
198
SMSC LAN9312
DATASHEET
SMSC [ SMSC CORPORATION ]
