Disable DHCP renewal fallback, recover after short power loss

Author: budulinek

arduino-modbus-rtu-tcp-gateway/01-interfaces.ino

@@ -114,14 +114,24 @@ void startEthernet() {
 
 void (*resetFunc)(void) = 0;  //declare reset function at address 0
 
+void checkEthernet() {
+  static byte attempts = 0;
+  IPAddress tempIP = Ethernet.localIP();
+  if (tempIP[0] == 0) {
+    attempts++;
+    if (attempts >= 3) {
+      resetFunc();
+    }
+  } else {
+    attempts = 0;
+  }
+  checkEthTimer.sleep(CHECK_ETH_INTERVAL);
+}
+
 #ifdef ENABLE_DHCP
 void maintainDhcp() {
   if (data.config.enableDhcp && dhcpSuccess == true) {  // only call maintain if initial DHCP request by startEthernet was successfull
-    byte maintainResult = Ethernet.maintain();
-    if (maintainResult == 1 || maintainResult == 3) {  // renew failed or rebind failed
-      dhcpSuccess = false;
-      startEthernet();  // another DHCP request, fallback to static IP
-    }
+    Ethernet.maintain();
   }
 }
 #endif /* ENABLE_DHCP */
@@ -208,7 +218,7 @@ void manageSockets() {
   byte webListening = MAX_SOCK_NUM;
   byte dataAvailable = MAX_SOCK_NUM;
   byte socketsAvailable = 0;
-  // SPI.beginTransaction(SPI_ETHERNET_SETTINGS);								// begin SPI transaction
+  SPI.beginTransaction(SPI_ETHERNET_SETTINGS);  // begin SPI transaction
   // look at all the hardware sockets, record and take action based on current states
   for (byte s = 0; s < maxSockNum; s++) {            // for each hardware socket ...
     byte status = W5100.readSnSR(s);                 //  get socket status...
@@ -294,8 +304,8 @@ void manageSockets() {
     disconSocket(oldest);
   }
 
-  // SPI.endTransaction();	// Serves to o release the bus for other devices to access it. Since the ethernet chip is the only device
-  // we do not need SPI.beginTransaction(SPI_ETHERNET_SETTINGS) or SPI.endTransaction()
+  SPI.endTransaction();  // Serves to o release the bus for other devices to access it. Since the ethernet chip is the only device
+  // we do not need SPI.beginTransaction(SPI_ETHERNET_SETTINGS) or SPI.endTransaction() ??
 }
 
 void disconSocket(byte s) {

arduino-modbus-rtu-tcp-gateway/advanced_settings.h

@@ -20,6 +20,7 @@ const uint16_t SCAN_TIMEOUT = 200;       // Timeout (ms) for Modbus scan request
 
 const byte MAC_START[3] = { 0x90, 0xA2, 0xDA };  // MAC range for Gheo SA
 const byte ETH_RESET_PIN = 7;                    // Ethernet shield reset pin (deals with power on reset issue on low quality ethernet shields)
+const uint16_t CHECK_ETH_INTERVAL = 2000;               // Interval (ms) to check SPI connection with ethernet shield
 const uint16_t ETH_RESET_DELAY = 500;            // Delay (ms) during Ethernet start, wait for Ethernet shield to start (reset issue on low quality ethernet shields)
 const uint16_t WEB_IDLE_TIMEOUT = 400;           // Time (ms) from last client data after which webserver TCP socket could be disconnected, non-blocking.
 const uint16_t TCP_DISCON_TIMEOUT = 500;         // Timeout (ms) for client DISCON socket command, non-blocking alternative to https://www.arduino.cc/reference/en/libraries/ethernet/client.setconnectiontimeout/

arduino-modbus-rtu-tcp-gateway/arduino-modbus-rtu-tcp-gateway.ino

@@ -22,9 +22,10 @@
   v6.1 2023-04-12 Code optimization
   v7.0 2023-07-21 Manual MAC, better data types
   v7.1 2023-08-25 Simplify EEPROM read and write, Tools page
+  v7.2 2023-XX-XX Disable DHCP renewal fallback, recover after short power loss
 */
 
-const byte VERSION[] = { 7, 1 };
+const byte VERSION[] = { 7, 2 };
 
 #include <SPI.h>
 #include <Ethernet.h>
@@ -167,7 +168,8 @@ void Timer::sleep(uint32_t sleepTimeMs) {
 
 MicroTimer recvMicroTimer;
 MicroTimer sendMicroTimer;
-Timer eepromTimer;  // timer to delay writing statistics to EEPROM
+Timer eepromTimer;    // timer to delay writing statistics to EEPROM
+Timer checkEthTimer;  // timer to check SPI connection with ethernet shield
 
 #define RS485_TRANSMIT HIGH
 #define RS485_RECEIVE LOW
@@ -242,6 +244,10 @@ void loop() {
     updateEeprom();
   }
 
+  if (CHECK_ETH_INTERVAL > 0 && checkEthTimer.isOver() == true) {
+    checkEthernet();
+  }
+
   if (rollover()) {
     resetStats();
     updateEeprom();