论坛 › NFC近场通信技术 › NFC P2P（点对点）通信例子 C语言

peter 发表于 2015-1-10 13:47:07

NFC P2P（点对点）通信例子 C语言

功能效果：本实例达到的效果是：实现两个PN532开发板之间的P2P通信（点对点传一个字符串“P2P transmit Sameple – SmartFire.cn”），两台电脑，分别插一个SmartNFC --PN532 开发板，请从我们官方淘宝店购买：http://item.taobao.com/item.htm?&id=19307275283&
一、修改libNFC的接口修改LIBNFC，指定到某个UART口，例如COM3，请看另一个文章：http://smartfire.cn/bbs/thread-32472-1-1.html

二、C程序代码
发送端代码#ifdef HAVE_CONFIG_H
#include "config.h"
#endif // HAVE_CONFIG_H

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>

#include <nfc/nfc.h>

#include "utils/nfc-utils.h"

#define MAX_FRAME_LEN 264

static nfc_device *pnd;

static void stop_dep_communication(int sig)
{
(void) sig;
if (pnd)
    nfc_abort_command(pnd);
else
    exit(EXIT_FAILURE);
}

int
main(int argc, const char *argv[])
{
nfc_target nt;
uint8_tabtRx;
uint8_tabtTx[] = "P2P transmit Sample--SmartFire.cn";//发送的数据--风火轮团队

if (argc > 1) {
    printf("Usage: %s\n", argv);
    return EXIT_FAILURE;
}

nfc_context *context;
nfc_init(&context);

pnd = nfc_open(context, NULL);
if (!pnd) {
    printf("Unable to open NFC device.\n");
    return EXIT_FAILURE;
}
printf("NFC device: %s\n opened", nfc_device_get_name(pnd));

signal(SIGINT, stop_dep_communication);

if (nfc_initiator_init(pnd) < 0) {
    nfc_perror(pnd, "nfc_initiator_init");
    goto error;
}

if (nfc_initiator_select_dep_target(pnd, NDM_PASSIVE, NBR_212, NULL, &nt, 1000) < 0) {
    nfc_perror(pnd, "nfc_initiator_select_dep_target");
    goto error;
}
print_nfc_target(nt, false);

printf("Sending: %s\n", abtTx);
int res;
if ((res = nfc_initiator_transceive_bytes(pnd, abtTx, sizeof(abtTx), abtRx, sizeof(abtRx), 0)) < 0) {
    nfc_perror(pnd, "nfc_initiator_transceive_bytes");
    goto error;
}

abtRx = 0;
printf("Received: %s\n", abtRx);

if (nfc_initiator_deselect_target(pnd) < 0) {
    nfc_perror(pnd, "nfc_initiator_deselect_target");
    goto error;
}

error:
nfc_close(pnd);
nfc_exit(context);
return EXIT_SUCCESS;
}
接收端代码#ifdef HAVE_CONFIG_H
#include "config.h"
#endif // HAVE_CONFIG_H

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>

#include <nfc/nfc.h>

#include "utils/nfc-utils.h"

#define MAX_FRAME_LEN 264

static nfc_device *pnd;

static void stop_dep_communication(int sig)
{
(void) sig;
if (pnd)
    nfc_abort_command(pnd);
else
    exit(EXIT_FAILURE);
}

int
main(int argc, const char *argv[])
{
uint8_tabtRx;
intszRx;
uint8_tabtTx[] = "Hello Mars!";

nfc_context *context;
nfc_init(&context);
#define MAX_DEVICE_COUNT 2
nfc_connstring connstrings;
size_t szDeviceFound = nfc_list_devices(context, connstrings, MAX_DEVICE_COUNT);
// Little hack to allow using nfc-dep-initiator & nfc-dep-target from
// the same machine: if there is more than one readers opened
// nfc-dep-target will open the second reader
// (we hope they're always detected in the same order)
if (szDeviceFound == 1) {
    pnd = nfc_open(context, connstrings);
} else if (szDeviceFound > 1) {
    pnd = nfc_open(context, connstrings);
} else {
    printf("No device found.\n");
    return EXIT_FAILURE;
}

if (argc > 1) {
    printf("Usage: %s\n", argv);
    return EXIT_FAILURE;
}

nfc_target nt = {
    .nm = {
      .nmt = NMT_DEP,
      .nbr = NBR_UNDEFINED
    },
    .nti = {
      .ndi = {
      .abtNFCID3 = { 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xff, 0x00, 0x00 },
      .szGB = 4,
      .abtGB = { 0x12, 0x34, 0x56, 0x78 },
      .ndm = NDM_UNDEFINED,
      /* These bytes are not used by nfc_target_init: the chip will provide them automatically to the initiator */
      .btDID = 0x00,
      .btBS = 0x00,
      .btBR = 0x00,
      .btTO = 0x00,
      .btPP = 0x01,
      },
    },
};

if (!pnd) {
    printf("Unable to open NFC device.\n");
    return EXIT_FAILURE;
}
printf("NFC device: %s opened\n", nfc_device_get_name(pnd));

signal(SIGINT, stop_dep_communication);

printf("NFC device will now act as: ");
print_nfc_target(nt, false);

printf("Waiting for initiator request...\n");
if ((szRx = nfc_target_init(pnd, &nt, abtRx, sizeof(abtRx), 0)) < 0) {
    nfc_perror(pnd, "nfc_target_init");
    goto error;
}

printf("Initiator request received. Waiting for data...\n");
if ((szRx = nfc_target_receive_bytes(pnd, abtRx, sizeof(abtRx), 0)) < 0) {
    nfc_perror(pnd, "nfc_target_receive_bytes");
    goto error;
}
abtRx[(size_t) szRx] = '\0';
printf("Received: %s\n", abtRx);

printf("Sending: %s\n", abtTx);
if (nfc_target_send_bytes(pnd, abtTx, sizeof(abtTx), 0) < 0) {
    nfc_perror(pnd, "nfc_target_send_bytes");
    goto error;
}
printf("Data sent.\n");

error:
nfc_close(pnd);
nfc_exit(context);
return EXIT_SUCCESS;
}
三、实验步骤    第一步，按以上修改libnfc，然后编译，得到的exe文件和libnfc.dll，如果不会编译，请看我的另一篇文章：http://smartfire.cn/forum.php?mod=viewthread&tid=499&extra=page%3D1
   第二步,把exe文件和libnfc.dll放到同一个文件夹，然后在windows下，CMD命令行进到这个目录


   第三步：硬件连接    A电脑连接一块SmartNFC --PN532 开发板，扮演target模式（卡模式），接受B传过来的数据并显示，B电脑连接一块SmartNFC --PN532 开发板，扮演主机模式，发送数据

默认是UART连接如下图http://img03.taobaocdn.com/imgextra/i3/56843193/T2Fl6BXjdXXXXXXXXX_!!56843193.jpg注意：一定要记得RX与TX交叉，就是串口板上的TX要接PN532开发板的RX，串口板上的RX接PN532的TX

    第四步：命令先操作A电脑，把pn532模拟成卡
A电脑，进到CMD，输入：nfc-dep-target.exe
http://en.smartfire.cn/bbs/data/attachment/forum/201305/08/193345f3ox1sdlxsdq5bfl.png.thumb.jpg
它会显示：Waiting for initiator request …等主机发过来的数据
B电脑CMD命令行进行libnfc目录，然后运行nfc-dep-initiator.exehttp://en.smartfire.cn/bbs/data/attachment/forum/201305/08/19350249mf1f9nmdzazwyc.jpg.thumb.jpg

它就开始在COM3去操作PN532开发板，通过它去发送我们程序里预设的符串“P2P transmit Sample--SmartFire.cn”
实现效果实拍两个PN532开发板，放在一起，RF对射       http://en.smartfire.cn/bbs/data/attachment/forum/201305/08/193638befr2b3rer4lltj4.jpg.thumb.jpg

整套测试系统如下http://en.smartfire.cn/bbs/data/attachment/forum/201305/08/1938179yrmw0nt55yxthw0.jpg.thumb.jpghttp://en.smartfire.cn/bbs/data/attachment/forum/201305/08/193819ryoiioqr9b1mmeb8.jpg.thumb.jpg


       http://en.smartfire.cn/bbs/data/attachment/forum/201305/08/19420928kcrk2ik226phh2.jpg.thumb.jpg
下面附件，是风火轮科技编译好的可执行文件，方便童鞋们下载测试，
平台：WIN7 64bit

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