nvSRAM stores data into NV cell during STORE operation which is triggered either by automatically during power fail (AutoStore) or can be initiated by the software sequence (Software Store) or a hardware pin (HSB Store). Similarly, data is recalled to SRAM cell from NV cells during AutoRecall during power up cycle or through software command (Software Recall) during normal operation.
After the Recall due to power cycle or through Software command, the data in the SRAM and NV cell becomes identical. During normal operation, all write and in the SRAM cell of nvSRAM and data is not stored in NV cells until a STORE command is initiated by the controller. If user application writes some data in SRAM locations and then decided to overwrite it with the previous data from NV cell then s/he can issue a Software Recall command which will overwrite the newly written data of SRAM cell with the data stored in NV cells.
Since nvSRAM is offered with three different inter options such as parallel, Serial SPI and Serial I2C, initiating Software Recall command will vary according to interface type.
In Parallel interface – Software Recall is initiated by reading from six specified address locations in a sequence.
In Serial Interface (SPI & I2C) – There is specific command for initiating a Software Recall.