Datasheet

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AT30TSE004A [DATASHEET]
Atmel-8868C-DTS-AT30TSE004A-Datasheet_122013
7.2.3 Acknowledge (ACK) Polling
An ACK polling routine can be implemented to optimize time sensitive applications that would not prefer waiting
the fixed maximum write cycle time and would prefer to know immediately when the Serial EEPROM write cycle
has completed to start a subsequent operation. Once the internally self timed write cycle has started (the Stop
condition during the 10
th
clock cycle at the end of the Write sequence), the Serial EEPROM inputs are disabled
and ACK polling can be initiated (see Figure 7-5). An ACK polling routine involves sending a valid Start
condition followed by the device address byte. While the write cycle is in progress, the device will not respond
with an ACK indicating the Serial EEPROM is busy writing data. Once complete, the device will ACK and the
next device operation can be started.
Note: The temperature sensor operations can be accessed during the write cycle to read the Temperature Register or
perform any other user desired temperature sensor operation.
Figure 7-5. Acknowledge Polling Flow Chart
7.2.4 Write Cycle Timing
The length of the self timed write cycle, or t
WR
, is defined as the amount of time from a valid Stop condition that
begins the internal write sequence to the Start condition of the first device address byte sent to the
AT30TSE004A that it subsequently responds to with an ACK. Figure 7-6 has been included to show this
measurement.
Figure 7-6. Write cycle Timing
Did
the Device
ACK?
Send Any
Write
Protocol
Send
Stop
Condition
to Initiate
Write Cycle
Send Start
Condition
Followed
by Valid
Device Address
Byte
Continue to
Next Operation
NO
YES
t
WR
Stop
Condition
Start
Condition
Data Word n
ACKD0
SDA
Stop
Conditio
n
SCL
89
ACK
First Acknowledge from the device
to a valid device address sequence after
write cycle is initiated. The minumum t
WR
can only be determined through
the use of an ACK Polling routine.
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