High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface
Datasheet
Sequential reads are used by the EEPROM Loader. Refer to Section 10.2.4, "EEPROM Loader" for
additional information.
For a register level description of a read operation, refer to Section 10.2.1, "EEPROM Controller
Operation," on page 138.
2
10.2.2.5
I C EEPROM Byte Writes
Following the device addressing, a data byte may be written to the EEPROM by outputting the data
after receiving the acknowledge from the EEPROM. The data byte is acknowledged by the EEPROM
2
slave and the I C master finishes the write cycle with a stop condition. If the EEPROM slave fails to
send an acknowledge, then the sequence is aborted and the EPC_TIMEOUT bit in the EEPROM
Command Register (E2P_CMD) is set.
2
Following the data byte write cycle, the I C master will poll the EEPROM to determine when the byte
write is finished. A start condition is sent followed by a control byte with a control code of 1010b,
chip/block select bits low, and the R/~W bit low. If the EEPROM is finished with the byte write, it will
2
respond with an acknowledge. Otherwise, it will respond with a no-acknowledge and the I C master
2
will repeat the poll. If the acknowledge does not occur within 30mS, a time-out occurs. Once the I C
master receives the acknowledge, it concludes by sending a start condition, followed by a stop
condition, which will place the EEPROM into standby.
2
Figure 10.4 illustrates typical I C EEPROM byte write.
Conclude
Data Cycle
Data Byte
Poll Cycle
Poll Cycle
Poll Cycle
Control Byte
Control Byte
Control Byte
A
C
K
A
C
K
A
C
K
A
C
K
A
C
K
D
7
D
6
D
5
D
4
D
3
D
2
D
1
D
0
... S
P
S
1
0
1
0
0
0
0
0
S
1
0
1
0
0
0
0
0
1
0
1
0
0
0
0
0
S P
R/~W
R/~W
R/~W
Chip / Block
Select Bits
Chip / Block
Select Bits
Chip / Block
Select Bits
Figure 10.6 I2C EEPROM Byte Write
For a register level description of a write operation, refer to Section 10.2.1, "EEPROM Controller
Operation," on page 138.
SMSC LAN9312
143
Revision 1.2 (04-08-08)
DATASHEET
SMSC [ SMSC CORPORATION ]
