本文以XC7A35TFGG484-2这款芯片为例，采用米联客FPGA开发板，用MIG核驱动DDR3内存。FPGA外接的晶振大小为50MHz，DDR3内存的驱动频率（ddr3_ck_p和ddr3_ck_n）为400MHz。选用的DDR3内存型号为MT41K128M16，内存容量为256MB。

首先用Clocking Wizard配置时钟，由50MHz倍频到200MHz，作为MIG的系统时钟（sys_clk_i）和参考时钟（clk_ref_i）。

用MMCM倍频，输入的时钟为50MHz：

输出的时钟为200MHz：

点击OK，产生IP核，方式选择默认的Out of context per IP即可：

然后选择添加MIG核：

这些保持默认。代码中我们用的是默认的接口，不使用AXI4接口，不需要勾选AXI4 Interface：

这个也不用管：

选择驱动的是DDR3内存：

Clock Period设为2500ps，这样DDR3内存的驱动频率就是400MHz。后面还要选择DDR3内存的型号和位宽。
MIG核最关键的配置就是时钟的配置。这里的4:1表示DDR3内存的驱动频率，和用户程序代码运行的时钟频率之比为4:1，DDR3运行于400MHz，那么用户程序就运行于100MHz。

MIG内部PLL倍频器的输入时钟为200MHz：

（为了方便期间，MIG PLL输入时钟、系统时钟和参考时钟全部采用Clocking Wizard产生的200MHz时钟）

系统时钟和参考时钟要选择No Buffer。

这个保持默认：

从外部ucf文件读DDR3内存的引脚配置：

导入UCF文件，然后Validate，OK：

MA703-35T_MIG.ucf文件的内容如下：

NET "ddr3_dq[0]"                             LOC = "P6"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[1]"                             LOC = "R1"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[2]"                             LOC = "M5"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[3]"                             LOC = "N4"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[4]"                             LOC = "N5"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[5]"                             LOC = "N2"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[6]"                             LOC = "M6"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[7]"                             LOC = "P1"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[8]"                             LOC = "L3"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[9]"                             LOC = "J4"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[10]"                            LOC = "M3"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[11]"                            LOC = "K4"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[12]"                            LOC = "M2"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[13]"                            LOC = "K3"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[14]"                            LOC = "L4"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dq[15]"                            LOC = "L5"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dm[0]"                             LOC = "P2"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dm[1]"                             LOC = "J6"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_dqs_p[0]"                          LOC = "P5"      |   IOSTANDARD = DIFF_SSTL15           ;                                 
NET "ddr3_dqs_n[0]"                          LOC = "P4"      |   IOSTANDARD = DIFF_SSTL15           ;                                 
NET "ddr3_dqs_p[1]"                          LOC = "M1"      |   IOSTANDARD = DIFF_SSTL15           ;                                 
NET "ddr3_dqs_n[1]"                          LOC = "L1"      |   IOSTANDARD = DIFF_SSTL15           ;                                 
NET "ddr3_addr[13]"                          LOC = "W5"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_addr[12]"                          LOC = "AA5"     |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_addr[11]"                          LOC = "AB7"     |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_addr[10]"                          LOC = "Y9"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_addr[9]"                           LOC = "Y4"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_addr[8]"                           LOC = "AA8"     |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_addr[7]"                           LOC = "AA4"     |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_addr[6]"                           LOC = "Y7"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_addr[5]"                           LOC = "AA3"     |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_addr[4]"                           LOC = "AB6"     |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_addr[3]"                           LOC = "Y2"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_addr[2]"                           LOC = "Y3"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_addr[1]"                           LOC = "AA6"     |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_addr[0]"                           LOC = "AB3"     |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_ba[2]"                             LOC = "W2"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_ba[1]"                             LOC = "AB5"     |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_ba[0]"                             LOC = "AB2"     |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_ck_p[0]"                           LOC = "T5"      |   IOSTANDARD = DIFF_SSTL15           ;                                 
NET "ddr3_ck_n[0]"                           LOC = "U5"      |   IOSTANDARD = DIFF_SSTL15           ;                                 
NET "ddr3_ras_n"                             LOC = "V2"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_cas_n"                             LOC = "AA1"     |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_we_n"                              LOC = "W1"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_reset_n"                           LOC = "W4"      |   IOSTANDARD = LVCMOS15              ;                                 
NET "ddr3_cke[0]"                            LOC = "Y6"      |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_odt[0]"                            LOC = "AB1"     |   IOSTANDARD = SSTL15                ;                                 
NET "ddr3_cs_n[0]"                           LOC = "Y1"      |   IOSTANDARD = SSTL15                ;                                 

这些保持默认：

同意完所有的协议后，生成MIG IP核，综合选项仍然选择Out of context per IP：

生成IP核后，可以在IP核里面的mig_7series_0.v里面看到这个IP核究竟有哪些引脚：

每个引脚的格式一目了然。

最后，在综合完自己的代码后，进入Schematic一看，可以看到DDR3的引脚早已配置好了，我们只需要配置其他的引脚就可以了。

也就是说，保存的pins.xdc里面是不包含DDR3引脚的配置的。DDR3引脚配置是专门在MIG IP核的文件夹里面有一个xdc文件。

 

工程建好了，IP核也配置好了，接下来就是编写代码了：https://blog.csdn.net/ZLK1214/article/details/111085879

MIG核自带的那个example工程很复杂，里面参数也很多，阅读起来很难懂。我们不用那个example工程，自己写代码调用IP核，简单易懂。

最后编译代码产生bit文件的时候，是没有报任何错误的，直接成功：