STTS424E02BDA3E STMICROELECTRONICS [STMicroelectronics], STTS424E02BDA3E Datasheet - Page 32

• Manufacturer Part Number: STTS424E02BDA3E
• Description: Memory module temperature sensor with a 2 Kb SPD EEPROM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

SPD EEPROM operation
5.5.1
5.5.2
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Byte write
After the Device Select Code and the address byte, the bus master sends one data byte. If
the addressed location is hardware write-protected, the device replies to the data byte with
NoAck, and the location is not modified. If, instead, the addressed location is not Write-
protected, the device replies with Ack. The bus master terminates the transfer by generating
a Stop condition, as shown in
Page write
The Page Write mode allows up to 16 bytes to be written in a single Write cycle, provided
that they are all located in the same page in the memory: that is, the most significant
memory address bits are the same. If more bytes are sent than will fit up to the end of the
page, a condition known as ‘roll-over’ occurs. This should be avoided, as data starts to
become overwritten in an implementation dependent way.
The bus master sends from 1 to 16 bytes of data, each of which is acknowledged by the
device if Write Control (WC) is Low. After each byte is transferred, the internal byte address
counter (the 4 least significant address bits only) is incremented. The transfer is terminated
by the bus master generating a Stop condition.
Figure 12. Write mode sequences in a non write-protected area of SPD
BYTE WRITE
PAGE WRITE
Figure
DEV SEL
DEV SEL
ACK
12.
DATA IN N
R/W
R/W
ACK
ACK
BYTE ADDR
BYTE ADDR
ACK
ACK
ACK
DATA IN 1
DATA IN
ACK
ACK
DATA IN 2
STTS424E02
AI01941