Launching Hello NiosII HW Config has Encountered a Problem

Hi,

I build a simple FPGA system: NiosII CPU, DDR Rame, SSRAM (Both are external), and other IP components. The sytem passed compilation and Runs Nios II Hello world program, if CPU exception and reset address space is assigned to DDR RAM, and program runs from DDR RAM.

But If I specifies the CPU exception and reset, and want to run program from SSRAM, then I got the following Error:

Launching Hello NiosII Hardware configuration has encountered a problem. Downloading ELF Process Failed.

Anyone has any ideas that what might be wrong?

Thank you,

David