External RAM Interface

 External RAM Interface

I am new to the ARM processor and Keil Realview environment. I am using STR912FA44W44 processor and ISSI64WV25616 as an external RAM.

I write a simple LED routine.
The GPIO 7.7 enables the external RAM as a chip select.
and I enable Bank1 of EMI for 16 bit mode.

In uVision3, the RAM base address 0x3c000000 is specified in the Options for Target -> Target.

After compiling and downloading the program into the internal flash of str912, the LED routine doesn't work. However, if I unmark the off-chip RAM at Options for Target and recompile the program and run it. The LED routine works.

I know I must miss something to use the external RAM. Highly appreciate if someone specifies in detail how to use the External RAM.