Question about RAM.

In my CC2430 datasheet it says:
"The CC2430 contains static RAM.
At power-on the contents of RAM is undefined.
The RAM size is 8 KB in total. The upper 4 KB of the RAM (XDATA memory locations 0xF000-0xFFFF) retains data in all power modes (see exception below)."


Does it mean that the upper 4 KB of the RAM store their data while MCU is powered off?

Thanks.

No.
If what you need is ram in power off mode you're looking for non-volitile memory.

What that is saying is the first 4kb are fully volatile all power down modes will invalidate it's contents, the last 4kb are static in all supported power down modes of the ram, except whatever (see exception bellow) refers to. Power down modes does NOT mean removing power from the IC.

Other power down modes they would be talking about are things like IDLE, SLEEP, plus others. The names are usually specific to the MCUs involved, but they almost all translate into just a few different common modes.

Full Power
Idle Mode
Sleep mode
Possible ability to shut down individual modules on the chip.