Set MX_SOCK_NUM to 8

Set maximum sockets to 8 as default. Set 4 sockets for W5200.

Author: budulinek

README.md

@@ -36,9 +36,7 @@ Screenshots of the web interface:
 * supports all Modbus function codes
 * settings can be changed via web interface, stored in EEPROM
 * diagnostics and Modbus RTU scan via web interface
-* optimized queue for Modbus requests
-  - prioritization of requests to responding slaves
-  - queue will accept only one requests to non-responding slaves
+* optimized queue for Modbus requests (queue will accept only one requests to non-responding slaves)
 
 ## How can I build it myself?
 Get the hardware (cheap clones from China are sufficient) and connect together:

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

@@ -83,10 +83,8 @@ void startEthernet() {
   Udp.begin(localConfig.udpPort);
   modbusServer.begin();
   webServer.begin();
-  // Ethernet library determines MAX_SOCK_NUM by Microcontroller RAM (not by Ethernet chip type).
-  // Therefore, for Arduino Mega + W5100, MAX_SOCK_NUM is wrongly set to 8
   if (Ethernet.hardwareStatus() == EthernetW5100) {
-    maxSockNum = 4;
+    maxSockNum = 4;  // W5100 chip never supports more than 4 sockets
   }
   dbg(F("[arduino] Server available at http://"));
   dbgln(Ethernet.localIP());
@@ -122,14 +120,15 @@ void maintainCounters() {
   // synchronize roll-over of data counters to zero, at 0xFFFFFF00 or 0xFF00 respectively
 #ifdef ENABLE_EXTRA_DIAG
   const unsigned long rollover = 0xFFFFFF00;
+  if (serialTxCount > rollover || serialRxCount > rollover || ethTxCount > rollover || ethRxCount > rollover) {
+    ethRxCount = 0;
+    ethTxCount = 0;
 #else
   const unsigned int rollover = 0xFF00;
+  if (serialTxCount > rollover || serialRxCount > rollover) {
 #endif /* ENABLE_EXTRA_DIAG */
-  if (serialTxCount > rollover || serialRxCount > rollover || ethTxCount > rollover || ethRxCount > rollover) {
     serialRxCount = 0;
     serialTxCount = 0;
-    ethRxCount = 0;
-    ethTxCount = 0;
   }
 }
 
@@ -139,29 +138,25 @@ void generateMac() {
   seed1 = 36969L * (seed1 & 65535L) + (seed1 >> 16);
   seed2 = 18000L * (seed2 & 65535L) + (seed2 >> 16);
   uint32_t randomBuffer = (seed1 << 16) + seed2; /* 32-bit random */
-
   for (byte i = 0; i < 3; i++) {
     localConfig.macEnd[i] = randomBuffer & 0xFF;
     randomBuffer >>= 8;
   }
 }
 
+// https://sites.google.com/site/astudyofentropy/project-definition/timer-jitter-entropy-sources/entropy-library/arduino-random-seed
 void CreateTrulyRandomSeed() {
   seed1 = 0;
-  nrot = 32;  // Must be at least 4, but more increased the uniformity of the produced
-  // seeds entropy.
-
+  nrot = 32;  // Must be at least 4, but more increased the uniformity of the produced seeds entropy.
   // The following five lines of code turn on the watch dog timer interrupt to create
   // the seed value
   cli();
   MCUSR = 0;
   _WD_CONTROL_REG |= (1 << _WD_CHANGE_BIT) | (1 << WDE);
   _WD_CONTROL_REG = (1 << WDIE);
   sei();
-
   while (nrot > 0)
     ;  // wait here until seed is created
-
   // The following five lines turn off the watch dog timer interrupt
   cli();
   MCUSR = 0;

arduino-modbus-rtu-tcp-gateway/02-modbus-tcp.ino

@@ -48,7 +48,9 @@ CircularBuffer<byte, reqQueueCount> queueRetries;    // queue of retry counters
 void recvUdp() {
   unsigned int packetSize = Udp.parsePacket();
   if (packetSize) {
+#ifdef ENABLE_EXTRA_DIAG
     ethRxCount += packetSize;
+#endif /* ENABLE_EXTRA_DIAG */
     byte udpInBuffer[modbusSize + 4];  // Modbus TCP frame is 4 bytes longer than Modbus RTU frame
     // Modbus TCP/UDP frame: [0][1] transaction ID, [2][3] protocol ID, [4][5] length and [6] unit ID (address).....
     // Modbus RTU frame: [0] address.....
@@ -98,7 +100,9 @@ void recvTcp() {
   EthernetClient client = modbusServer.available();
   if (client) {
     unsigned int packetSize = client.available();
+#ifdef ENABLE_EXTRA_DIAG
     ethRxCount += packetSize;
+#endif /* ENABLE_EXTRA_DIAG */
     byte tcpInBuffer[modbusSize + 4];  // Modbus TCP frame is 4 bytes longer than Modbus RTU frame
     // Modbus TCP/UDP frame: [0][1] transaction ID, [2][3] protocol ID, [4][5] length and [6] unit ID (address).....
     // Modbus RTU frame: [0] address.....

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

@@ -65,19 +65,14 @@ const int modbusSize = 256;          // size of a MODBUS RTU frame (determines s
 #define mySerial Serial              // define serial port for RS485 interface, for Arduino Mega choose from Serial1, Serial2 or Serial3         
 #define RS485_CONTROL_PIN 6          // Arduino Pin for RS485 Direction control, disable if you have module with hardware flow control
 const byte ethResetPin = 7;          // Ethernet shield reset pin (deals with power on reset issue of the ethernet shield)
-const byte scanCommand[] = {0x03, 0x00, 0x00, 0x00, 0x01};  // Command sent during Modbus RTU Scan. Slave is detected if any response (even error) is received.
+const byte scanCommand[] = { 0x03, 0x00, 0x00, 0x00, 0x01 };  // Command sent during Modbus RTU Scan. Slave is detected if any response (even error) is received.
 
 // #define DEBUG            // Main Serial (USB) is used for printing some debug info, not for Modbus RTU. At the moment, only web server related debug messages are printed.
 #define debugSerial Serial
 
-#ifdef MAX_SOCK_NUM           //if the macro MAX_SOCK_NUM is defined 
-// #undef MAX_SOCK_NUM           //un-define it
-// #define MAX_SOCK_NUM 8        //redefine it with the new value
-#endif 
-
 /****** EXTRA FUNCTIONS ******/
 
-// these do not fit into the limited flash memory of Arduino Uno/Nano, uncomment if you have board with more memory
+// these do not fit into the limited flash memory of Arduino Uno/Nano, uncomment if you have a board with more memory
 // #define ENABLE_DHCP            // Enable DHCP (Auto IP settings)
 // #define ENABLE_EXTRA_DIAG      // Enable per socket diagnostics, run time counter
 
@@ -137,6 +132,11 @@ const byte configStart = 128;
 #define UDP_TX_PACKET_MAX_SIZE modbusSize   //redefine it with the new value
 #endif 
 
+#ifdef MAX_SOCK_NUM     // Ethernet.h library determines MAX_SOCK_NUM by Microcontroller RAM (not by Ethernet chip type).
+#undef MAX_SOCK_NUM     // Ignore the RAM-based limitation on the number of sockets.
+#define MAX_SOCK_NUM 8  // Use all sockets supported by the ethernet chip.
+#endif
+
 byte maxSockNum = MAX_SOCK_NUM;
 
 bool dhcpSuccess = false;
@@ -199,9 +199,11 @@ uint16_t crc;
 #define RS485_TRANSMIT    HIGH
 #define RS485_RECEIVE     LOW
 byte scanCounter = 0;
-enum state : byte
-{
-  IDLE, SENDING, DELAY, WAITING
+enum state : byte {
+  IDLE,
+  SENDING,
+  DELAY,
+  WAITING
 };
 enum state serialState;
 unsigned int charTimeout;
@@ -228,14 +230,13 @@ unsigned long ethRxCount = 0;
 #else
 unsigned int serialTxCount = 0;
 unsigned int serialRxCount = 0;
-unsigned int ethTxCount = 0;
-unsigned int ethRxCount = 0;
+// unsigned int ethTxCount = 0;
+// unsigned int ethRxCount = 0;
 #endif /* ENABLE_EXTRA_DIAG */
 
 /****** SETUP: RUNS ONCE ******/
 
-void setup()
-{
+void setup() {
   CreateTrulyRandomSeed();
 
   // is config already stored in EEPROM?
@@ -262,8 +263,7 @@ void setup()
 
 /****** LOOP ******/
 
-void loop()
-{
+void loop() {
   recvUdp();
   recvTcp();
   processRequests();