Download But Verify Failed

Hi All,

I am using Nios Dev Board with MT48LC2M32B2 SDRAM(It is the only execute memory). When I make a software example and download it to sdram, it displays in nios IDE console:

<div class='quotetop'>QUOTE </div>

--- Quote Start ---

Using cable "ByteBlasterII [LPT1]", device 1, instance 0x00

Pausing target processor: OK

Reading System ID at address 0x02000880: verified

Downloading 00800000 ( 0%)

Downloaded 1KB in 0.0s

Verifying 00800000 ( 0%)

Verify failed

Leaving target processor paused[/b]

--- Quote End ---

I find it is so popular problem with nios. Almost all designs using sdram will have the problem. Now, I only know that it has to do with Synchronization of sdram_clock and nios_system_clock, and can deal with the right phase shift value setting.

But here I also have questions to ask about the problem.

1. About the verify failed problem, what&#39;s problem on earth? How many problems it should include?

2. I have sealed a new cyclone board with MT sdram, but I do not know clearly about how to set phase shift correctly in PLL setting. Can someone tell me how to alleviate clock skew between the SDRAM controller core and the SDRAM chip.

3. Can I simulate the timing in QUARTUS II of them? Or, can I use oscillograph(I use oscillograph, but can not observe)?

I want the answer.

Thank you,

LiangYi