From 9fab2428230e5bfdc985c4a4e210170e0523b7af Mon Sep 17 00:00:00 2001
From: Ole Artz <ole.artz@t-online.de>
Date: Tue, 14 Jul 2020 10:27:03 +0200
Subject: [PATCH] E_UART: Create Telnet Server

---
 .../LANTelnetToSerial_Board.ino               | 171 ++++++++++++++++++
 1 file changed, 171 insertions(+)
 create mode 100644 esp32/EthernetUART/LANTelnetToSerial_Board/LANTelnetToSerial_Board.ino

diff --git a/esp32/EthernetUART/LANTelnetToSerial_Board/LANTelnetToSerial_Board.ino b/esp32/EthernetUART/LANTelnetToSerial_Board/LANTelnetToSerial_Board.ino
new file mode 100644
index 0000000..fc939c4
--- /dev/null
+++ b/esp32/EthernetUART/LANTelnetToSerial_Board/LANTelnetToSerial_Board.ino
@@ -0,0 +1,171 @@
+/*
+#####################################################
+# ###                                           ### #
+# ### CODE for ESP32 of LANToSerial_Board_264   ### #
+# ### for START TELNET SERVER                   ### #
+# ### for LAN to Serial Connection              ### #
+# ###                                           ### #
+# ### author: O.Artz                            ### #
+# ###                                           ### #
+# ###                                           ### #
+# ### UPDATE 2020-07-10                         ### #
+# ###                                           ### #
+#####################################################
+
+ETH MAC: 24:6F:28:1E:C5:57 
+IPv4: 192.168.8.64
+Telnet: 192.168.8.64 23
+
+Visual Status via Board LEDs:
+ETH Start                 -> Green LED blink for 1 sec
+Telnet work               -> Green LED on
+ETH Disconnected/stopped  -> Orange LED on
+*/
+
+//load needed Libaries
+#include <ETH.h>
+#include <WiFi.h>
+
+//how many clients should be able to telnet to this ESP32
+#define MAX_SRV_CLIENTS 1
+
+WiFiServer server(23);
+WiFiClient serverClients[MAX_SRV_CLIENTS];
+
+//used to check the number every time, cause could changed
+volatile static bool eth_connected = false;
+
+void WiFiEvent(WiFiEvent_t event)
+{
+  switch (event){
+    case SYSTEM_EVENT_ETH_START:
+      Serial.println("ETH Started");
+      //set eth hostname here
+      digitalWrite(2,LOW);
+      digitalWrite(15,HIGH);
+      delay(500);
+      digitalWrite(15, LOW); 
+      ETH.setHostname("esp32-ethernet");
+      break;
+      
+    case SYSTEM_EVENT_ETH_CONNECTED:
+      Serial.println("ETH Connected");
+      break;
+      
+    case SYSTEM_EVENT_ETH_GOT_IP:
+      Serial.print("ETH MAC: ");
+      Serial.print(ETH.macAddress());
+      Serial.print(", IPv4: ");
+      Serial.print(ETH.localIP());
+      if (ETH.fullDuplex()) {
+        Serial.print(", FULL_DUPLEX");
+      }
+      Serial.print(", ");
+      Serial.print(ETH.linkSpeed());
+      Serial.println("Mbps");
+      eth_connected = true;
+      break;
+      
+    case SYSTEM_EVENT_ETH_DISCONNECTED:
+      Serial.println("ETH Disconnected");
+      digitalWrite(15,LOW);
+      digitalWrite(2,HIGH);
+      eth_connected = false;
+      break;
+      
+    case SYSTEM_EVENT_ETH_STOP:
+      Serial.println("ETH Stopped");
+      digitalWrite(15,LOW);
+      digitalWrite(2,HIGH);
+      eth_connected = false;
+      break;
+      
+    default:
+      break;
+  }
+}
+
+void setup()
+{
+  pinMode(2, OUTPUT); // yellow LED
+  pinMode(15, OUTPUT); // green LED 
+  Serial.begin(115200);
+  Serial.println("\nConnecting");
+  WiFi.onEvent(WiFiEvent);
+  delay(1000);
+  //start UART and the server
+  ETH.begin(1,17,23,18,ETH_PHY_LAN8720,ETH_CLOCK_GPIO0_IN);
+  server.begin();
+  server.setNoDelay(true);
+
+  while (eth_connected == false);
+
+  Serial.print("Ready! Use 'telnet ");
+  Serial.print(ETH.localIP());
+  Serial.println(" 23' to connect");
+  //visual status for telnet work
+  digitalWrite(2,LOW);
+  digitalWrite(15,HIGH);
+  Serial.print(WiFi.status());
+}
+
+void loop()
+{
+  uint8_t i;
+  if (WiFi.status() == 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()) Serial.write(serverClients[i].read());
+        }
+      }
+      else {
+        if (serverClients[i]) {
+          serverClients[i].stop();
+        }
+      }
+    }
+    //check UART for data
+    if(Serial.available()) {
+      size_t len = Serial.available();
+      uint8_t sbuf[len];
+      Serial.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();
+    }
+    setup();
+  }*/
+}
-- 
2.43.0