STM32H750B-DK与Python TCP客户端连接失败问题求助

我尝试通过TCP从STM32H750B-DK发送字符串到Python程序并打印输出。STM32端作为TCP Server，Python端计划作为TCP客户端，但遇到以下问题：

• Python端绑定0.0.0.0时，程序显示已监听，但无法和STM32建立连接
• Python端绑定STM32的IP地址169.254.211.100时，抛出OSError: [WinError 10049]错误
• 使用Hercules工具可正常连接STM32并接收数据，特此求助问题原因及解决方法。

STM32端TCP Server代码 #

/*
 * tcpserver.c
 *
 *  Created on: Apr 20, 2022
 *      Author: controllerstech.com
 */


#include "lwip/opt.h"

#include "lwip/api.h"
#include "lwip/sys.h"

#include "tcpserver.h"
#include "string.h"
static struct netconn *conn, *newconn;
static struct netbuf *buf;
static ip_addr_t *addr;
static unsigned short port;
char msg[100];
char smsg[200];

char b[10] = {'0'};


/**** Send RESPONSE every time the client sends some data ******/
static void tcp_thread(void *arg)
{
    err_t err, accept_err, recv_error;

    /* Create a new connection identifier. */
    conn = netconn_new(NETCONN_TCP);

    if (conn!=NULL)
    {
        /* Bind connection to the port number 7. */
        err = netconn_bind(conn, IP_ADDR_ANY, 146);

        if (err == ERR_OK)
        {
            /* Tell connection to go into listening mode. */
            netconn_listen(conn);

            while (1)
            {
                /* Grab new connection. */
                accept_err = netconn_accept(conn, &newconn);

                /* Process the new connection. */
                if (accept_err == ERR_OK)
                {

                    /* receive the data from the client */
                    while (netconn_recv(newconn, &buf) == ERR_OK)
                    {
                        /* Extrct the address and port in case they are required */
                        addr = netbuf_fromaddr(buf);  // get the address of the client
                        port = netbuf_fromport(buf);  // get the Port of the client

                        /* If there is some data remaining to be sent, the following process will continue */
                        do
                        {

                            strncpy (msg, buf->p->payload, buf->p->len);   // get the message from the client
                            if (msg[0]==103){
                                b[0] = '1';
                            }
                            else{
                                b[0] = 'h';
                            }


                            // Or modify the message received, so that we can send it back to the client
                            int len = sprintf (smsg, "\"%s\" was sent by the Server\n", b);

                            netconn_write(newconn, smsg, len, NETCONN_COPY);  // send the message back to the client
                            memset (msg, '\0', 100);  // clear the buffer
                        }
                        while (netbuf_next(buf) >0);

                        netbuf_delete(buf);
                    }

                    /* Close connection and discard connection identifier. */
                    netconn_close(newconn);
                    netconn_delete(newconn);
                }
            }
        }
        else
        {
            netconn_delete(conn);
        }
    }
}



void tcpserver_init(void)
{
  sys_thread_new("tcp_thread", tcp_thread, NULL, DEFAULT_THREAD_STACKSIZE,osPriorityNormal);
}

原Python端代码（存在角色错误） #

import socket

SERVER_IP = "0.0.0.0"
SERVER_PORT = 146

# Create a socket
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.bind((SERVER_IP, SERVER_PORT))
server_socket.listen(1)

print("Server listening on", SERVER_IP, "port", SERVER_PORT)

while True:
    client_socket, client_address = server_socket.accept()
    print("Connection from:", client_address)

    data = client_socket.recv(1024)
    if data:
        received_variable = int(data.decode())
        print("Received variable:", received_variable)

    client_socket.close()

错误信息 #

line 43, in <module>
    server_socket.bind((SERVER_IP, SERVER_PORT))
OSError: [WinError 10049] The requested address is not valid in its context

问题分析 #

1. 核心错误：TCP角色完全混淆
   STM32代码已经实现为TCP Server（调用netconn_listen监听端口146，等待客户端连接），但你的Python代码却也实现了TCP Server的逻辑（bind+listen+accept），两者都在等待对方发起连接，自然无法建立会话。而Hercules是作为TCP Client主动连接STM32 Server，所以能正常工作。

2. WinError 10049错误原因
   绑定STM32的IP169.254.211.100时出错，是因为这个IP不属于你的Windows主机网卡，bind操作只能绑定本机已存在的IP地址或者0.0.0.0（代表监听本机所有网卡），绑定其他设备的IP地址必然会触发地址无效的错误。

3. 绑定0.0.0.0无法连接的原因
   此时Python处于Server模式，和STM32的Server模式形成“双等”状态，没有任何一方主动发起连接请求，因此永远无法建立连接。

解决方法 #

将Python代码修改为TCP Client逻辑，主动连接STM32 Server：

import socket

# STM32服务器的IP和端口
STM32_SERVER_IP = "169.254.211.100"
STM32_SERVER_PORT = 146

# 创建TCP客户端socket
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
    # 主动连接STM32服务器
    client_socket.connect((STM32_SERVER_IP, STM32_SERVER_PORT))
    print("已成功连接到STM32服务器")

    # 根据STM32代码逻辑，需要先发送数据才会触发回复
    # 发送字符'g'（ASCII码103），对应STM32中msg[0]==103的判断
    client_socket.send(b'g')

    # 接收STM32返回的数据
    data = client_socket.recv(1024)
    if data:
        print("收到STM32数据:", data.decode())
finally:
    # 关闭连接
    client_socket.close()

补充说明 #

• 确保Windows主机与STM32处于同一网络环境，且能正常ping通169.254.211.100
• 如果需要持续接收STM32的数据，可以将接收逻辑放入循环中
• STM32代码逻辑是收到客户端数据后才会回复，因此Python客户端必须先发送数据才能触发STM32的返回

内容的提问来源于stack exchange，提问作者AK16