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LAN9311 Datasheet, PDF (144/461 Pages) SMSC Corporation – Two Port 10/100 Managed Ethernet Switch with 16-Bit Non-PCI CPU Interface
Two Port 10/100 Managed Ethernet Switch with 16-Bit Non-PCI CPU Interface
Datasheet
10.2.2.5
I2C 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
slave and the I2C 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.
Following the data byte write cycle, the I2C 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
respond with an acknowledge. Otherwise, it will respond with a no-acknowledge and the I2C master
will repeat the poll. If the acknowledge does not occur within 30mS, a time-out occurs. Once the I2C
master receives the acknowledge, it concludes by sending a start condition, followed by a stop
condition, which will place the EEPROM into standby.
Figure 10.4 illustrates typical I2C EEPROM byte write.
Data Cycle
Poll Cycle
Poll Cycle
Poll Cycle
Conclude
... Data Byte
Control Byte
Control Byte
A
C
K
D
7
D
6
D
5
D
4
D
3
D
2
D
1
D
0
A
C
K
P
S
1
0
1
0
0
0
0
0
A
C
K
S
1
0
1
0
0
0
0
0
A
C
K
Control Byte
A
S1 0 1 0 0 0 0 0C SP
K
Chip / Block R/~W
Select Bits
Chip / Block R/~W
Select Bits
Figure 10.6 I2C EEPROM Byte Write
Chip / Block R/~W
Select Bits
For a register level description of a write operation, refer to Section 10.2.1, "EEPROM Controller
Operation," on page 139.
Revision 2.0 (02-14-13)
144
DATASHEET
SMSC LAN9311/LAN9311i