How to store file from RS232 to SDRAM/FLASH/SRAM ?

The lrvrl converter may be the following:

http://focus.ti.com/lit/ds/symlink/trsf3221e.pdf

for UART.... you should write it or get something like this:

http://soursecodes.blogspot.com/

You need only the RX part and the modules which serve it...

For writing into SRAM look at the DPR specification. It is usually like this:

CLK: ____________|--------------

_________

xxxxxxxxxx WR DATA xxxxxxxxxxx

-------------

_________

xxxxxxxxxxx WR ADDR xxxxxxxxxxx

-------------

WR_EN ____|-----------|__________