tcp_server.ino

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#include <ELClient.h>
#include <ELClientSocket.h>
 
// IP address for this demo is a local IP.
// Replace it with the IP address where you have a TCP socket server running
char * const tcpServer PROGMEM = "192.168.0.102";
// Port for this demo is the port used by the TCP socket server.
// Replace it with the port that your TCP socket server is listening to
uint16_t const tcpPort PROGMEM = 7002;
 
//###########################################################
// For ARDUINO UNO WIFI with I2C to serial chip!
//###########################################################
// Serial port to ESP8266
#include <SC16IS750.h>
SC16IS750 i2cuart = SC16IS750(SC16IS750_PROTOCOL_I2C,SC16IS750_ADDRESS_AA);
 
// Initialize a connection to esp-link using the I2Cuart chip of the Arduino Uno WiFi board for
// SLIP messages.
ELClient esp(&i2cuart);
 
//###########################################################
// For boards using the hardware serial port!
//###########################################################
// Initialize a connection to esp-link using the normal hardware serial port both for
// SLIP and for debug messages.
//ELClient esp(&Serial, &Serial);
 
// Initialize a TCP socket client on the connection to esp-link
ELClientSocket tcp(&esp);
// Connection number for tcp
int tcpConnNum;
 
// Timer value to send out data 
uint32_t wait;
// Time to wait between sending out data
uint32_t waitTime;
// Flag for wifi connection
boolean wifiConnected = false;
 
// Parse error codes and returns error message as char *
// Definitions from error values from espconn.h (Espressif SDK)
// #define ESPCONN_OK           0  /**< No error, everything OK.   */
// #define ESPCONN_MEM         -1  /**< Out of memory.             */
// #define ESPCONN_TIMEOUT     -3  /**< Timeout.                   */
// #define ESPCONN_RTE         -4  /**< Routing problem.           */
// #define ESPCONN_INPROGRESS  -5  /**< Operation in progress.     */
// #define ESPCONN_MAXNUM      -7  /**< Total number exceeds the maximum limitation. */
 
// #define ESPCONN_ABRT        -8  /**< Connection aborted.    */
// #define ESPCONN_RST         -9  /**< Connection reset.      */
// #define ESPCONN_CLSD       -10  /**< Connection closed.     */
// #define ESPCONN_CONN       -11  /**< Not connected.         */
 
// #define ESPCONN_ARG        -12  /**< Illegal argument.      */
// #define ESPCONN_IF         -14  /**< UDP send error.        */
// #define ESPCONN_ISCONN     -15  /**< Already connected.     */
 
char* const errTxt[] PROGMEM = {"No error, everything OK.","Out of memory.","Unknown code.","Timeout.","Routing problem.","Operation in progress.",
                    "Unknown code.","Total number exceeds the maximum limitation.","Connection aborted.","Connection reset.","Connection closed.",
                    "Not connected.","Illegal argument.","Unknown code.","UDP send error.","Already connected."};
char * getErrTxt(int16_t commError) {
    commError = commError*-1;
    if (commError <= 15) {
        return (char *) pgm_read_word (&errTxt[commError]);
    } else {
        return (char *) pgm_read_word (&errTxt[2]); // Unknown code
    }
}
 
// Callback for TCP socket, called if data was sent or received
// Receives socket client number, can be reused for all initialized TCP socket connections
void tcpCb(uint8_t resp_type, uint8_t client_num, uint16_t len, char *data) {
    Serial.println("tcpCb connection #"+String(client_num));
    if (resp_type == USERCB_SENT) {
        Serial.println("\tSent " + String(len) + " bytes over client#" + String(client_num));
    } else if (resp_type == USERCB_RECV) {
        char recvData[len+1]; // Prepare buffer for the received data
        memcpy(recvData, data, len); // Copy received data into the buffer
        recvData[len] = '\0'; // Terminate the buffer with 0 for proper printout!
 
        Serial.println("\tReceived " + String(len) + " bytes over the server on connection #" + String(client_num));
        Serial.println("\tReceived: " + String(recvData));
        // TODO add some functions to react to the received data
        char respData[len+11]; // Prepare buffer for the response data
        char *respHdr = "Received: ";
        memcpy (respData, respHdr, 10);
        memcpy(&respData[10], recvData, len); // Copy received data into the buffer
        respData[len+10] = '\0';
        Serial.println("\tSend response: " + String(respData));
        tcp.send(respData);
    } else if (resp_type == USERCB_RECO) {
        if (len != -11) { // ignore "not connected" error, handled in USERCB_CONN
            Serial.print("\tConnection problem: ");
            Serial.println(getErrTxt(len));
        }
    } else if (resp_type == USERCB_CONN) {
        if (len == 0) {
            Serial.println("\tDisconnected");
        } else {
            Serial.println("\tConnected");
        }
    } else {
        Serial.println("Received invalid response type");
    }
}
 
// Callback made from esp-link to notify of wifi status changes
// Here we print something out and set a global flag
void wifiCb(void *response) {
    ELClientResponse *res = (ELClientResponse*)response;
    if (res->argc() == 1) {
        uint8_t status;
        res->popArg(&status, 1);
 
        if(status == STATION_GOT_IP) {
            Serial.println(F("WIFI CONNECTED"));
            wifiConnected = true;
        } else {
            Serial.print(F("WIFI NOT READY: "));
            Serial.println(status);
            wifiConnected = false;
        }
    }
}
 
void setup() {
    Serial.begin(115200);
//###########################################################
// For ARDUINO UNO WIFI with I2C to serial chip!
//###########################################################
    i2cuart.begin(9600);
 
    Serial.println(F("EL-Client starting!"));
 
    // Sync-up with esp-link, this is required at the start of any sketch and initializes the
    // callbacks to the wifi status change callback. The callback gets called with the initial
    // status right after Sync() below completes.
    esp.wifiCb.attach(wifiCb); // wifi status change callback, optional (delete if not desired)
    bool ok;
    do {
        ok = esp.Sync();            // sync up with esp-link, blocks for up to 2 seconds
        if (!ok) Serial.println(F("EL-Client sync failed!"));
    } while(!ok);
    Serial.println(F("EL-Client synced!"));
 
    // Wit for WiFi to be connected. 
    esp.GetWifiStatus();
    ELClientPacket *packet;
    Serial.print(F("Waiting for WiFi "));
    if ((packet=esp.WaitReturn()) != NULL) {
        Serial.print(F("."));
        Serial.println(packet->value);
    }
    Serial.println("");
 
    // Set up the TCP socket server to wait for a client on port <>,
    // it just sets-up stuff on the esp-link side and waits until a client sends some data
    tcpConnNum = tcp.begin(tcpServer, tcpPort, SOCKET_TCP_SERVER, tcpCb); // SOCKET_SERVER ==> accept connections
    if (tcpConnNum < 0) {
        Serial.println(F("TCP socket setup failed, try again in 10 seconds after reboot"));
        delay(10000);
        asm volatile ("  jmp 0");
    } else {
        Serial.println(String(tcpServer)+":"+String(tcpPort)+" is served over connection number # = "+String(tcpConnNum));
    }
    Serial.println(F("EL-TCP ready"));
}
 
void loop() {
    // process any callbacks coming from esp_link
    esp.Process();
}