exception when trying to write to certain memory locations.

Good afternoon,

I am writing code for a OMAP3530 EVM board useing CCSv5.3 with SYS/BIOS support.  When I try to write to or read from any of the registers assosiated with the general purpose memory controller (GPMC) in debug I get exceptions.  My suspition is that this is more to do with ccs and the gel file being used than the actual device hence posting here. 

In the gel file the memory for the GPMC lives inside this part of the memory map

 /* !! FOLLOWING MEM SPACE TO BE CONFIGURED PROPERLY !!*/    

GEL_MapAddStr(0x68000000, 0, 0x98000000, "R|W|AS4"    , 0);  /* TO BE CONFIGURED */

The gel file that sets up the SDRAM writes to registers inside this area without any issues but my code cannot when I am trying to setup and access the NAND memory.  Can anyone suggest what I need to change to fix this?

Many thanks

Sean