使用Cubemx配置UDP通信实验2

1、打开生成的文件，在while函数下添加此函数，暂时忽略主函数中的udp_echoserver_init(); ，不影响连接测试

2、我们已经配置生成好了程序文件，把程序下载到开发板中，下面开始配置电脑端的IP，重点是网段号一定要一样！！！！！！！！

3、接下来看看我们与电脑的连接状态，windows+r，输入cmd

ping成功，说明电脑与开发板已经建立了连接，下面，开始发送数据

7、在配置发送数据前，这里我们需要添加一个文件，这是ST自带的库文件，也就是上图主函数调用的 udp_echoserver_init();（对ping不影响，但是网络数据发送需要用到）
`/**

---

• @file udp_echoserver.c
• @author MCD Application Team
• @version V1.1.0
• @date 31-July-2013
• @brief UDP echo server

---

• @attention

• Licensed under MCD-ST Liberty SW License Agreement V2, (the “License”);

• You may not use this file except in compliance with the License.

• You may obtain a copy of the License at:

•    http://www.st.com/software_license_agreement_liberty_v2
  

• Unless required by applicable law or agreed to in writing, software

• distributed under the License is distributed on an “AS IS” BASIS,

• WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

• See the License for the specific language governing permissions and

• limitations under the License.

---

*/

/* Includes ------------------------------------------------------------------/
#include “main.h”
#include “lwip/pbuf.h”
#include “lwip/udp.h”
#include “lwip/tcp.h”
//#include “ip_addr.h”
#include
#include
#include “udp_echoserver.h”
/ Private typedef -----------------------------------------------------------/
/ Private define ------------------------------------------------------------/
#define UDP_SERVER_PORT 8080 / define the UDP local connection port /
#define UDP_CLIENT_PORT 8080 / define the UDP remote connection port */

/* Private macro -------------------------------------------------------------/
/ Private variables ---------------------------------------------------------/
/ Private function prototypes -----------------------------------------------*/
void udp_echoserver_receive_callback(void *arg, struct udp_pcb *upcb, struct pbuf *p, const struct ip4_addr *addr, u16_t port);

/* Private functions ---------------------------------------------------------*/

/**

• @brief Initialize the server application.
• @param None
• @retval None
  */
  void udp_echoserver_init(void)
  {
  struct udp_pcb *upcb;
  err_t err;

/* Create a new UDP control block */
upcb = udp_new();

if (upcb)
{
/* Bind the upcb to the UDP_PORT port /
/ Using IP_ADDR_ANY allow the upcb to be used by any local interface */
err = udp_bind(upcb, IP_ADDR_ANY, UDP_SERVER_PORT);

  if(err == ERR_OK)
  {
    /* Set a receive callback for the upcb */
		 HAL_GPIO_WritePin(LED0_GPIO_Port, LED0_Pin, GPIO_PIN_RESET);
    udp_recv(upcb, udp_echoserver_receive_callback, NULL);
			
  }
  else
  {
    udp_remove(upcb);
   // printf("can not bind pcb");
  }

}
else
{

// printf("can not create pcb");

}
}

/**

• @brief This function is called when an UDP datagrm has been received on the port UDP_PORT.
• @param arg user supplied argument (udp_pcb.recv_arg)
• @param pcb the udp_pcb which received data
• @param p the packet buffer that was received
• @param addr the remote IP address from which the packet was received
• @param port the remote port from which the packet was received
• @retval None
  */
  uint8_t receivebuf[2000];
  uint8_t send_buf[2] = {0xdd,0xcc};
  int receivelen = 0;
  void udp_echoserver_receive_callback(void *arg, struct udp_pcb *upcb, struct pbuf *p,const struct ip4_addr *addr, u16_t port)
  {
  struct pbuf *pq;
  if(p!=NULL)
  {
  memset(receivebuf,0,2000); //数据接收缓存区清0
  receivelen = p->len;
  memcpy(receivebuf,p->payload,p->len);
  pbuf_free§;

udp_connect(upcb, addr, UDP_CLIENT_PORT); //连接
// pq = pbuf_alloc(PBUF_TRANSPORT,2,PBUF_POOL);//allocate memory
// pbuf_take(pq,(char*)send_buf,2);//copy data to buf

pq=pbuf_alloc(PBUF_TRANSPORT,strlen((char*)receivebuf),PBUF_POOL); //申请内存
if(pq) // 如果成功，将接收到的数据寄存
{
	pq->payload=(void*)receivebuf; 

} 
	
udp_send(upcb,pq);//send udp data 将接收到的数据发送出去，做一个循环试验
udp_disconnect(upcb);
pbuf_free(pq);

}

}

/************************ © COPYRIGHT STMicroelectronics *END OF FILE/

下面是头文件

/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved. 
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 * 
 */
#ifndef __ECHO_H__
#define __ECHO_H__


void udp_echoserver_init(void);

#endif /* __MINIMAL_ECHO_H */

8、此时把程序下载到开发板后，就可以实现我在电脑端通过网络助手使用UDP协议向开发板发送数据，开发板接收到数据活就会回传过来在上位机显示