I have a project using lpc1343 and fm25l04 (an spi based FRAM memory). To keep the data safe during power off cycle its best to keep the CS signal high. Is there any routine in uC to invoke interrupt, when voltage goes below a certain threshold (e.g. 2.8V) ?
Check the user manual for BOD (brown out detection).
E.g. section 3.5.35 in UM10375.
Obviously, you code the specific details yourself.
It may vary slightly for specific 1300 family members, but that is the manual for the LPC1343.
However, it is better (IMNSHO) to have a pull up on the CS line in the hardware design in the first place.
Hope that helps, Mike.