Using cable "USB-Blaster [USB-0]", device 1, instance 0x00
Pausing target processor: not responding.
Resetting and trying again: FAILED
Leaving target processor paused
网上总结三点原因致使这个问题的发生：
1、复位键的管脚没有对应好，导致报错；
2、给sdram的clk，与cpu的clk没有滞后-75的相位；
3、如果用锁相环输出clk的话不要直接飞线到锁相环的输入端口，不然也会报错。
这种通信错误的情况基本上是由于PIN定义错误或者是复位错误。
我总结这主要看两方面：reset和clk：
（一）reset管脚绑定是否正确，以及芯片型号是否正确。
（二）clk对应的时钟频率是否正确，比较移植过来的是20M，倍频ration：相位之后-75。实际用的是50M。
网上有说芯片修正版本为第4版，速度是7.5ns（PC133 CL=3）。50M时PLL偏移是-40。低速条件下不偏移也可以。
其次，Nios II在Win中开发有几个文件要设置兼容模式，不用的引脚要设置为三态也是经常引起错误的小原因。
Using cable "USB-Blaster [USB-0]", device 1, instance 0x00
Pausing target processor: OK
Reading System ID at address 0x00001800: verified
Initializing CPU cache (if present)
OK
Downloading 01000020 ( 0%)
Downloaded 57KB in 1.3s (43.8KB/s)
Verifying 01000020 ( 0%)
Verify failed between address 0x1000020 and 0x100E0CB
Leaving target processor paused
结果SOPC里面的器件型号没改过来，改完一些之后还是有版本不匹配的问题。
Pausing target processor: OK
Reading System ID at address 0x00001800:
ID value verified
Timestamp value does not match: image on board is older than expected
Read timestamp 13:51:51 2015/10/19; expected 20:23:41 2015/10/19
The software you are downloading may not run on the system which is currently
configured into the device. Please download the correct SOF or recompile.
Restarting target processor
默认的Timestamp是1445258994，实际上要改为1445258956
Using cable "USB-Blaster [USB-0]", device 1, instance 0x00
Pausing target processor: OK
Reading System ID at address 0x00001800: verified
Initializing CPU cache (if present)
OK
Downloading 04000020 ( 0%)
Downloaded 57KB in 1.3s (43.8KB/s)
Verifying 04000020 ( 0%)
Verify failed between address 0x4000020 and 0x400E0CB
Leaving target processor paused