Question

利用教程中的提示，我编写了一个简单的wifi服务器和客户端，该服务器和客户端仅将通过wifi从串行线（使用USB连接到PC的连接）接收的字符中继到另一个对等方，并相应地使用inc / dec变量（请参见下面的代码）。我使用Arduino IDE（1.8.9）用纯C / C ++编写了此代码。我遇到的问题是该代码仅在重启后才能正常工作（我必须从模块上拔下USB电缆，然后再次插回）。如果仅按模块上的硬件复位按钮，或者在发送新版本的代码后（大多数情况下），一切正常，除了Serial.available（）或Serial.read（）函数。他们只是看不到通过USB /串行线从PC接收到任何东西。但是重新插入USB并重新连接Putty终端程序（即重新打开电源）可以解决该问题，然后一切又恢复了。重启电源后，它始终可以正常工作，但大多数情况下，在按下RST按钮（或上载新版本）后，该失败。当重置模块而没有完全断电时，ESP串行模块会以某种方式保持卡住或无法正确初始化。服务器和客户端上的行为相同。将模块替换为其他模块-结果相同。我使用昨天通过Arduino开发板管理器下载的最新NodeMCU / ESP开发板设置。请问您有什么解决办法的提示吗？

代码：

服务器：

#include <ESP8266WiFi.h>

const char* ssid = "my ssid"; //replace this with your WiFi network name
const char* password = "my passwd"; //replace this with your WiFi network password

WiFiServer server(12345);
int a;

void setup()
{
  a = 0;
  pinMode(D5, OUTPUT);  // piezo spkr
  delay(1000);
  Serial.begin(115200);
  delay(1000);
  tone(D5, 1720);

  Serial.flush();  //irrelevant whether this is here or not
  Serial.print("Wifi.begin()");
  WiFi.begin(ssid, password);

  Serial.println();
  Serial.print("Connecting");
  while (WiFi.status() != WL_CONNECTED)
  {
    delay(500);
    Serial.print(".");
  }
  tone(D5, 220);

  Serial.println("success!");
  Serial.print("Server IP Address is: ");
  Serial.println(WiFi.localIP());

  delay(1000);
  noTone(D5);

  server.begin();
}

int read_and_process_packet(WiFiClient *client)
{
  char packet_type = client->read();
  switch (packet_type)
  {
    case 'a': a--; Serial.println(a); break;
    case 'q': a++; Serial.println(a); break;
    case '-': return 0;
  }
  return 1;
}

void loop() {
  WiFiClient client = server.available();
  if (client) {

    if (client.connected()) {
      Serial.println("Connected to client");

      while (client.connected())
      {
        if (!read_and_process_packet(&client)) break;
        if (Serial.available())
        {
          char c = Serial.read();
          client.write(c);
        }
        delay(50);
      }
      client.stop();
      Serial.println("Client left");
    }
  }
  delay(1);
}

客户端：

#include <ESP8266WiFi.h>

// Replace these with your WiFi network settings
const char* ssid = "my ssid"; //replace this with your WiFi network name
const char* password = "my passwd"; //replace this with your WiFi network password

int a;

WiFiClient client;
char server_ip[20];

void setup()
{
  a = 0;
  pinMode(D5, OUTPUT);
  delay(1000);

  Serial.begin(115200);
  delay(1000);
  Serial.flush();  //irrelevant whether this is here or not

  Serial.print("Enter server IP: ");

  char *p = server_ip;
  for (int i = 0; i < 4; i++)
  {
    int ip = read_number();
    p = print_num(p, ip);  
    if (i < 3) 
      p = print_char(p, '.');
  }
  Serial.println();

  tone(D5, 1720);

  Serial.print("Wifi.begin()");
  WiFi.begin(ssid, password);

  Serial.println();
  Serial.print("Connecting");
  while (WiFi.status() != WL_CONNECTED)
  {
    delay(500);
    Serial.print(".");
  }
  tone(D5, 220);

  Serial.println("success!");
  Serial.print("IP Address is: ");
  Serial.println(WiFi.localIP());

  delay(100);
  noTone(D5);

  Serial.print("connecting to ");
  Serial.print(server_ip);
  Serial.print(":");
  Serial.println(12345);

  if (!client.connect(server_ip, 12345))
  {
    Serial.println("Could not connect to the server.");
    while (1);
  }
  tone(D5, 440, 50); 
}

int read_number()
{
  int x = 0;
  while (1) {
    if (Serial.available())
    {
      int c = Serial.read();
      Serial.write(c);
      if ((c >= '0') && (c <= '9'))
        x = x * 10 + (c - '0');
      else return x;
    }
    delay(100);
  }
}

char *print_num(char *p, int num)
{
  if (num == 0) *(p++) = '0'; 
  else 
  {
    if (num < 0) { *(p++) = '-'; num = -num; }
    long q = 1;
    while (q <= num) q *= 10;
    while (q > 1)
    {
      q /= 10;
      *(p++) = (num / q) + '0';
      num %= q;
    }
  }
  *p = 0;
  return p;
}

char * print_char(char *p, int c)
{
  *(p++) = c;
  *p = 0;
  return p;
}

int read_and_process_packet(WiFiClient *client)
{
  char packet_type = client->read();
  switch (packet_type)
  {
    case 'a': a--; Serial.println(a); break;
    case 'q': a++; Serial.println(a); break;
    case '-': return 0;
  }
  return 1;
}

void loop() 
{
  if (client.connected()) {
      Serial.println("Connected to server");

      while (client.connected())
      {
        if (Serial.available())
        {
          char c = Serial.read();
          client.write(c);
        }
        if (!read_and_process_packet(&client)) break;
        delay(1);
      }
      client.stop();
  }
  delay(1);
}

NodeMCU（ESP-12E）需要重启后才能使Serial.read（）工作

0 个答案: