使用VisualStudio读写NI FPGA板卡实例(基于FPGA Interface C API Generator）

实验平台说明：安装了NI LabVIEW 2015 32bit版本，安装了NI FPGA Interface C API Generator，安装了硬件PCIe-7842R；安装了Visual Studio 2015(下载的C API Generator说明是针对VS2013，不过实验测试发现vs2015可以使用)；按照官网给的例子进行实验http://www.ni.com/tutorial/8638/en/，只测试了FPGA板卡模拟输入功能，没有写模拟输出功能。官网例子是采用NI公司的LabWindows/CVI上位机软件。

实验步骤：

在LabVIEW中新建FPGA工程，命名为FPGA.vi

此工程中，FPGA和上位机有四个接口：3个参数输入接口（Samples等等），1个数据读取接口（FIFO），接口通信通过PCIe进行。编译该工程，得到bitfile文件

　　2.打开FPGA Interface C API Generator，导入之前用LabVIEW编译生成的FPGA bitfile，点击generate，生成了几个个文件：1.FPGA bitfile; 2.NiFpga.c;3.NiFpga.h;4.NiFpga_FPGA.h；

其中NiFpga_FPGA.h包含了应用程序中函数调用需要的常量，和上述读写结构的地址信息

NiFpga.c和NiFpga.h对所有工程都是一样的，包含了调用NI FPGA的各种系统函数。

3.新建visual studio控制台应用程序，添加上述几个文件

　　4.NiFpga.c设置编译属性，选择No Precompile,如下。（如果不这样设置，编译的时候会因C/C++编译问题而报错）

5.编译上位机程序，主要是打开FPGA(完成下载bitfile到FPGA的任务)，按照地址读写FPGA中的接口，关闭FPGA等操作。测试程序如下：

 1 // ConsoleApplication1.cpp : Defines the entry point for the console application.
 2 //
 3 // NIFPGATest.cpp : Defines the entry point for the console application.
 4 //
 5 #include "stdafx.h"
 6 #include "NiFpga_FPGA.h"
 7 #include <malloc.h>
 8 
 9 int main()
10 {
11     /* must be called before any other calls */
12     printf("Initializing...
");
13     NiFpga_Status status = NiFpga_Initialize();
14     if (NiFpga_IsNotError(status))
15     {
16         NiFpga_Session session;
17         /* opens a session, downloads the bitstream, and runs the FPGA */
18         printf("Opening a session...
");
19         /* opens a session, downloads the bitstream, but does not run the FPGA */
20         NiFpga_MergeStatus(&status, NiFpga_Open(NiFpga_FPGA_Bitfile, NiFpga_FPGA_Signature,
21             "RIO0", NiFpga_OpenAttribute_NoRun, &session));
22         if (NiFpga_IsNotError(status))
23         {
24             /* declare variables for output and input */
25             double numSamples, aorate, airate;
26             uint16_t threshold = 0;
27             uint32_t r, timeout = 10000/* 10 seconds */;
28             NiFpga_Bool overLimit;
29             int16_t *data = NULL;
30             numSamples = 10;
31             airate = 1000;
32             /* allocate size for the samples to read */
33             data = (int16_t*)malloc(sizeof(int16_t) * numSamples);
34 
35             /* write the number of samples and loop rate to the FPGA VI */
36             NiFpga_MergeStatus(&status, NiFpga_WriteI32(session, NiFpga_FPGA_ControlI32_Samples, numSamples));
37             NiFpga_MergeStatus(&status, NiFpga_WriteU32(session, NiFpga_FPGA_ControlU32_LoopPeriod, airate));
38             NiFpga_MergeStatus(&status, NiFpga_WriteI16(session, NiFpga_FPGA_ControlI16_Threshold, threshold));
39 
40             /* run the FPGA application */
41             printf("Running the FPGA...
");
42             NiFpga_MergeStatus(&status, NiFpga_Run(session, 0));
43 
44             /* read the DMA FIFO */
45             NiFpga_MergeStatus(&status, NiFpga_ReadFifoI16(session, NiFpga_FPGA_TargetToHostFifoI16_FIFO,
46                 data, numSamples, timeout, &r));
47 
48             /* read the Over Limit? boolean */
49             NiFpga_MergeStatus(&status, NiFpga_ReadBool(session, NiFpga_FPGA_IndicatorBool_OverLimit,
50                 &overLimit));
51 
52             /* close the session now that we're done */
53             printf("Closing the session...
");
54             NiFpga_MergeStatus(&status, NiFpga_Close(session, 0));
55         }
56         /* must be called after all other calls */
57         printf("Finalizing...
");
58         NiFpga_MergeStatus(&status, NiFpga_Finalize());
59     }
60     /* check if anything went wrong */
61     if (NiFpga_IsError(status))
62     {
63         printf("Error %d!
", status);
64         printf("Press <Enter> to quit...
");
65         getchar();
66     }
67 
68     return status;
69 }

参考文献：

官网给出的R系列FPGA的C API用法说明http://www.ni.com/tutorial/8638/en/
电脑上给出的FPGA Interface C API Generator的example