Datasheet

35
AT30TSE752A/754A/758A [DATASHEET]
Atmel-8854G-DTS-AT30TSE752A-754A-758A-Datasheet_102014
Figure 9-2. Copy Nonvolatile Registers to Volatile Registers
9.2 Copy Volatile Registers to Nonvolatile Registers
The Copy Volatile Registers to Nonvolatile Registers command allows the contents of the Configuration Register, T
LOW
Limit Register, and T
HIGH
Limit Register to be copied into the Nonvolatile Configuration Register, Nonvolatile T
LOW
Limit
Register, and Nonvolatile T
HIGH
Limit Register. The Copy Volatile Registers to Nonvolatile Registers command can be
used in the event that the Volatile Data Registers are modified and it is desired for that newly modified data to become
the new power-up/reset defaults.
To copy the contents of the Volatile Data Registers into the Nonvolatile Data Registers, the Master must first initiate a
Start condition followed by the AT30TSE752A/754A/758A device address byte (1001AAA0 where “AAA” corresponds to
the hard-wired A
2-0
address pins). After the AT30TSE752A/754A/758A has received the proper address byte, the device
will send an ACK to the Master. The Master must then send the command byte of 48h for the Copy Volatile Registers to
Nonvolatile Registers operation. After the command byte of 48h has been sent, the AT30TSE752A/754A/758A will send
another ACK to the Master. After the Master has subsequently issued a Stop or repeated Start condition, the
AT30TSE752A/754A/758A will begin the internally self-timed copy operation. The copy process will take place in a
maximum time of t
COPYW
during which time the NVRBSY bit in the Configuration Register will indicate that the nonvolatile
registers are busy. If the Master issues a repeated Start condition instead of a Stop condition, the
AT30TSE752A/754A/758A will abort the copy operation and the contents of the Nonvolatile Data Registers will not be
changed.
The Copy Volatile Registers to Nonvolatile Registers command will be ignored and no operation will be performed under
the following conditions: the nonvolatile registers are already busy (the NVRBSY bit of the Configuration Register is in the
Logic 1 state), the volatile and nonvolatile registers are currently locked (the RLCK bit of the Nonvolatile Configuration
Register is in the Logic 1 state), or the volatile and nonvolatile registers are permanently locked down (the RLCKDWN bit
of the Nonvolatile Configuration Register is in the Logic 1 state); however, the device will still respond with an ACK to
indicate that it received the command byte even though the copy process will not be performed.
Care must be taken when copying the Volatile Data Registers to the Nonvolatile Data Registers in order to accommodate
the associated program time and finite program endurance limit. Power must not be removed from the device during the
internally self-timed copy/program cycle. If power is removed prior to the completion of the copy/program cycle, then the
contents of the nonvolatile registers cannot be guaranteed. In addition, the contents of the nonvolatile registers may
become corrupt if programmed more than the maximum allowed number of Writes.
Figure 9-3. Copy Volatile Registers to Nonvolatile Registers
SCL
SDA
Address Byte
Command Byte
Start
by
Master
ACK
from
Slave
ACK
from
Slave
Stop
by
Master
MSB MSB
1 0 0 1 A A A 0 0 1 0 1 1 1 0 0 0 0
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
SCL
SDA
Address Byte
Command Byte
Start
by
Master
ACK
from
Slave
ACK
from
Slave
Stop
by
Master
MSB MSB
1 0 0 1 A A A 0 0 0 1 0 0 1 0 0 0 0
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9