fstab もトラップ

糞設計のsystemdが軌道を途中で止めるのでなにもできなくなる
ESP32 のシリアルサーバー繋げと言うのか・。

とりあえず/etc/fstabはこうする

proc /proc proc defaults 0 0
/dev/mmcblk0p1 /boot vfat defaults 0 0
/dev/mmcblk0p2 / ext4 defaults,noatime 0 0

しかたねーので、esp32devモジュールでtelnetシリアルサーバー作って繋げておくことにする。
ほんとらずぱいくそくそ...

/*
  WiFiTelnetToSerial - Example Transparent UART to Telnet Server for ESP32

  Copyright (c) 2017 Hristo Gochkov. All rights reserved.
  This file is part of the ESP32 WiFi library for Arduino environment.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/
#include <WiFi.h>
#include <WiFiMulti.h>
#include <WiFi.h>
#include <ESPmDNS.h>
#include <WiFiUdp.h>
#include <ArduinoOTA.h>

WiFiMulti wifiMulti;

//how many clients should be able to telnet to this ESP32
#define MAX_SRV_CLIENTS 1
const char* ssid = "xxxxxxxx";
const char* password = "xxxxxxxx";

WiFiServer server(23);
WiFiClient serverClients[MAX_SRV_CLIENTS];

HardwareSerial Serial1(2);  // UART1/Serial1 pins 16,17
// 17 tx
// 16 rx

void setup() {
  
  //start UART and the server
  Serial1.begin(115200);
  Serial.begin(115200);

  Serial.println("Booting");
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  while (WiFi.waitForConnectResult() != WL_CONNECTED) {
    Serial.println("Connection Failed! Rebooting...");
    delay(5000);
    ESP.restart();
  }
  
  ArduinoOTA.setHostname("myesp32");
  ArduinoOTA
    .onStart([]() {
      String type;
      if (ArduinoOTA.getCommand() == U_FLASH)
        type = "sketch";
      else // U_SPIFFS
        type = "filesystem";

      // NOTE: if updating SPIFFS this would be the place to unmount SPIFFS using SPIFFS.end()
      Serial.println("Start updating " + type);
    })
    .onEnd([]() {
      Serial.println("\nEnd");
    })
    .onProgress([](unsigned int progress, unsigned int total) {
      Serial.printf("Progress: %u%%\r", (progress / (total / 100)));
    })
    .onError([](ota_error_t error) {
      Serial.printf("Error[%u]: ", error);
      if (error == OTA_AUTH_ERROR) Serial.println("Auth Failed");
      else if (error == OTA_BEGIN_ERROR) Serial.println("Begin Failed");
      else if (error == OTA_CONNECT_ERROR) Serial.println("Connect Failed");
      else if (error == OTA_RECEIVE_ERROR) Serial.println("Receive Failed");
      else if (error == OTA_END_ERROR) Serial.println("End Failed");
    });

  ArduinoOTA.begin();
   
  server.begin();
  server.setNoDelay(true);
  
  Serial.print("Ready! Use 'telnet ");
  Serial.print(WiFi.localIP());
  Serial.println(" 23' to connect");
  
}

void loop() {
  uint8_t i;
  
  ArduinoOTA.handle();
  
  if (wifiMulti.run() == WL_CONNECTED) {
    //check if there are any new clients
    if (server.hasClient()){
      for(i = 0; i < MAX_SRV_CLIENTS; i++){
        //find free/disconnected spot
        if (!serverClients[i] || !serverClients[i].connected()){
          if(serverClients[i]) serverClients[i].stop();
          serverClients[i] = server.available();
          if (!serverClients[i]) Serial.println("available broken");
          Serial.print("New client: ");
          Serial.print(i); Serial.print(' ');
          Serial.println(serverClients[i].remoteIP());
          break;
        }
      }
      if (i >= MAX_SRV_CLIENTS) {
        //no free/disconnected spot so reject
        server.available().stop();
      }
    }
    //check clients for data
    for(i = 0; i < MAX_SRV_CLIENTS; i++){
      if (serverClients[i] && serverClients[i].connected()){
        if(serverClients[i].available()){
          //get data from the telnet client and push it to the UART
          while(serverClients[i].available()) Serial1.write(serverClients[i].read());
        }
      }
      else {
        if (serverClients[i]) {
          serverClients[i].stop();
        }
      }
    }
    //check UART for data
    if(Serial1.available()){
      size_t len = Serial1.available();
      uint8_t sbuf[len];
      Serial1.readBytes(sbuf, len);
      //push UART data to all connected telnet clients
      for(i = 0; i < MAX_SRV_CLIENTS; i++){
        if (serverClients[i] && serverClients[i].connected()){
          serverClients[i].write(sbuf, len);
          delay(1);
        }
      }
    }
  }
  else {
    Serial.println("WiFi not connected!");
    for(i = 0; i < MAX_SRV_CLIENTS; i++) {
      if (serverClients[i]) serverClients[i].stop();
    }
    delay(1000);
  }
}

HiLetgo ESP32 ESP-32S NodeMCU開発ボード2.4GHz WiFi + Bluetoothデュアルモード