Failed Executing

[Altera_Forum]

Hi all, 

 I Quartus Web Edition 10.1, I loaded a project nios FPGA. (Terasic DE1)  only with on-chip memory, the run goes well, When I put the sdram, I get:  Failed Executing: [nios2-download '- = USB-Blaster cable on localhost [USB-0]', - device = 1, - instance = 0, - g, -  An exception stack trace is not available.  Using cable "USB-Blaster [USB-0]", device 1, instance 0x00 Already processor is paused Reading System ID at address 0x01009878: verified Initializing CPU cache (if present) OK  Downloading 00800000 (0%) Downloading 008051D0 (98%) Downloading 01004000 (99%) Downloaded 21KB in 0.3s (70.0KB / s)  Verifying 00800000 (0%) Between verify failed address 0x800000 and 0x8050DB Leaving target processor paused  jtag my configuration is: USB-Blaster [USB-0] 020B30DD EP2C15/20 Node 19104600 Node 0C006E00 Node 00086E00  can anyone help me? Thank you all.

[Altera_Forum]

SDRAM has special clock skew requirements, therefore you can't use the same clock with NIOS. If I remember correctly, the SDRAM clock needs to lead the NIOS clock by 3 ns. 

 Use a PLL to generate a clock that leads the NIOS clock by 3 ns and use it for the SDRAM.

[Altera_Forum]

I did it but still does not work. 

 Thank you for answer!