Changes

  }

  }

CRC (Cyclic Redundancy Check) is an error-detecting code using for detect accidental changes to RAW data. The algorithm how to calculate CRC-16 (also known as CRC-16/IBM) you will find below.

RC(Cyclic Redundancy Check) is an error - detecting code using for detect accidental changes to RAW data.

The algorithm how to calculate CRC - 16(also known as CRC - 16 / IBM) you will find below.

var crc = {

var crc = {

    extractCRC: function(message){

    extractCRC: function (message) {

        crcData = message.slice(message.length-2,message.length);

        crcData = message.slice(message.length - 2, message.length);

        return crcData[0] * 256 + crcData[1];

        return crcData[0] * 256 + crcData[1];

    },<br>

    },

    crcCam: function(message, previous_crc){

    calculateCRC: function(message, previous_crc) {

        payload = message.slice(2, message.length-2);

        crc = 0x0000;

        let idx = 0;

        let crc = 0x0000;

        crcpoly = 0x8408;

 

        /*At this point you should start with the init value for CRC calculation. Init value for

        let payload_length = message.length - 6;  

        * the first packet is zero and for the upcoming packets it is the CRC value of the previous package

 

        */

        /* the payload is separated from the message header and CRC (4 bytes ofset + length)*/

        crc = previous_crc<br>

        let payload = message.slice(4, 4 + payload_length);

        while (idx < payload.length) {

 

            /* Use XOR operation for initial value and payload */

        /* Init value for the first message is zero and for the upcoming messages it is the CRC value of the previous message */

            crc ^= payload[idx];

        crc = previous_crc;

            bitcounter = 0;<br>

            while (bitcounter < 8) {

        for (idx = 0; idx < payload_length; idx++) {

                crcFirstBit = crc & bitOne;

                crc >>= 1;<br>

 

                if (crcFirstBit) {

            /* Use XOR operation for initial value and payload */

                    crc ^= crcpoly;

            crc ^= payload[idx];

                }

 

            }

            for (bit = 0; bit < 8; bit++) {

                let carry_bit = crc & 0x01;

                crc >>= 0x01;

        return crc;

                if (carry_bit != 0) {

    }

                    crc ^= crc_poly;

};

                }

exports.crc = crc;

            }

        return crc;

    }

};

exports.crc = crc;

==File transfer visual flow==

==File transfer visual flow==