Post edited by ST moderator mainly for the code sharing.
i want to use simple socket based communication . using socket API.
nucleo-F746ZG connected directly to the linux laptop through ethernet cable (Orange led is ON , on both side). i make controller as client and laptop as server . my server is always listen mode but my controller not able to send any data .
In Freertos option i didnt changes anything . enabled as CMSIS_v2.
LWIP enables . in that DHCP disabled
Ethernet is enabled . didnt changed anything .
Clock configuration
tcp_clinet.c
/*
* tcp_client.c
*
* Created on: 02-Jun-2026
* Author: sawati
*/
#include "lwip/sockets.h" /* socket, connect, send, recv */
#include "lwip/netdb.h" /* inet_addr */
#include "cmsis_os.h" /* osDelay */
#include <string.h>
#include <stdio.h>
#include "tcp_client.h"
#define SERVER_IP "169.254.0.220" /* your laptop IP */
#define SERVER_PORT 5000
void TCP_Client_Task(void)
{
/* client code here */
HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_2); // or your LED pin
HAL_Delay(500);
int sock;
struct sockaddr_in server_addr;
char msg[] = "Hello Laptop";
sock = socket(AF_INET,SOCK_STREAM,0);
if(sock < 0)
{
return;
}
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(5001);
server_addr.sin_addr.s_addr = inet_addr(SERVER_IP);
if(connect(sock,(struct sockaddr *)&server_addr,sizeof(server_addr)) < 0)
{
closesocket(sock);
return;
}
while(1)
{
send(sock, msg, strlen(msg), 0);
HAL_Delay(1000);
}
}
server.c
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
int main()
{
int server_fd;
int client_fd;
struct sockaddr_in server_addr;
struct sockaddr_in client_addr;
char buffer[100];
socklen_t len;
server_fd = socket(AF_INET, SOCK_STREAM, 0);
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = INADDR_ANY;
server_addr.sin_port = htons(5001);
bind(server_fd,
(struct sockaddr *)&server_addr,sizeof(server_addr));
listen(server_fd, 1);
printf("Waiting for STM32...\n");
len = sizeof(client_addr);
client_fd = accept(server_fd,(struct sockaddr *)&client_addr,&len);
printf("STM32 Connected\n");
while(1)
{
memset(buffer,0,sizeof(buffer));
int n = recv(client_fd,buffer,sizeof(buffer)-1,0);
if(n > 0)
{
printf("Received: %s\n",buffer);
}
}
}
[Part Number] :
STM32-NUCLEO-F746ZG
Ethernet cable
Linux laptop :
PRETTY_NAME="Ubuntu 22.04.3 2024.11.13 LTS (Cubic 2024-11-14 12:23)"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.5 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy
[Environment] :
STM32_MX : 6.17.0
STM32_IDE : 2.1.1
[Schematics] : Refer from google.
What i am trying to do : TCP/IP Socket communication .
I have NUCLEO-F746 controller and linux laoptop .
Both connected through Ethernet cable.
i want NUCLEO-F746ZG as client and laptop as server .
[Details] : I want to use socket API .
socket() , bind() , listen() , accept() , connect() , send() , recv() ,close()
For use above API's i enabled FREERTOS in MX and then LWIP_SOCKET option is automatically enabled.
but i added USART3 for debugging , so on minicom terminal print is not coming.
But when i disable FREERTOS that time USART3 print is displyed on minicom terminal , but not able to enable LWIP_SOCKET option in MX .
[Expected behavior] : simple socket based communication
Server is in listen mode . client can be connect and simple communication is done .
[How to reproduce] : above i shared steps to" what i trying to do" you can follow those steps.
client .c
int sock;
struct sockaddr_in server_addr;
char tx_buffer[100];
char rx_buffer[100];
strcpy (msg , "before Socket created\r\n");
HAL_UART_Transmit(&huart3,
(uint8_t*)msg,
strlen(msg),
HAL_MAX_DELAY);
sock = socket(AF_INET, SOCK_STREAM, 0);
strcpy (msg , "after Socket created\r\n");
HAL_UART_Transmit(&huart3,
(uint8_t*)msg,
strlen(msg),
HAL_MAX_DELAY);
if(sock < 0)
{
char msg[] = "Socket Failed\r\n";
HAL_UART_Transmit(&huart3,(uint8_t*)msg,strlen(msg),HAL_MAX_DELAY);
}
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(5000);
inet_aton("169.254.0.220",&server_addr.sin_addr);
strcpy (msg ,"before connect created\r\n");
HAL_UART_Transmit(&huart3,
(uint8_t*)msg,
strlen(msg),
HAL_MAX_DELAY);
if(connect(sock,(struct sockaddr*)&server_addr,sizeof(server_addr)) < 0)
{
char msg[] = "Connect Failed\r\n";
HAL_UART_Transmit(&huart3,
(uint8_t*)msg,
strlen(msg),
HAL_MAX_DELAY);
}
else
{
char msg[] = "Connected\r\n";
HAL_UART_Transmit(&huart3,
(uint8_t*)msg,
strlen(msg),
HAL_MAX_DELAY);
}
while(1)
{
strcpy(tx_buffer, "Hello From STM32");
send(sock,
tx_buffer,
strlen(tx_buffer),
0);
int len = recv(sock,
rx_buffer,
sizeof(rx_buffer)-1,
0);
if(len > 0)
{
rx_buffer[len] = '\0';
HAL_UART_Transmit(&huart3,
(uint8_t*)rx_buffer,
strlen(rx_buffer),
HAL_MAX_DELAY);
HAL_UART_Transmit(&huart3,
(uint8_t*)"\r\n",
2,
HAL_MAX_DELAY);
}
HAL_Delay(1000);
}
server.py
# server.py
import socket
HOST = "169.254.0.220" # listen on all interfaces
PORT = 5000
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((HOST, PORT))
s.listen(5)
print(f"Listening on port {PORT} ...")
while True:
conn, addr = s.accept()
with conn:
print(f"Connected from {addr}")
while True:
data = conn.recv(1024)
if not data:
break
print(f"Received: {data.decode(errors='replace')}", end="")
conn.sendall(b"ACK\r\n") # optional reply
want to know :
I read we can use 3 types of API's
Socket()
Netconn
Raw
How can i identify which one will select ??
