<div id="readability-page-1" class="page"><div id="SE-bcf6738e-8f87-4907-a649-4e86f91dde12">
                            <p id="SE-3a1ba160-a8c8-4e27-bb5d-59888bbf8c8b"><span id="SE-fcc35396-6144-4ab1-afee-7ae6cf60e32e">이전에 CRC-8/MAXIM 을 구현해 봤고 이번엔 CRC-16/MODBUS를 파이썬과 C로 작성해 봤다.</span></p>
                        </div><div id="SE-79573d78-ec1e-498b-9ca3-033c8bd88058">
                                    <p>crc16_table = [0x0000, 0xc0c1, 0xc181, 0x0140, 0xc301, 0x03c0, 0x0280, 0xc241, 
    0xc601, 0x06c0, 0x0780, 0xc741, 0x0500, 0xc5c1, 0xc481, 0x0440, 
    0xcc01, 0x0cc0, 0x0d80, 0xcd41, 0x0f00, 0xcfc1, 0xce81, 0x0e40, 
    0x0a00, 0xcac1, 0xcb81, 0x0b40, 0xc901, 0x09c0, 0x0880, 0xc841, 
    0xd801, 0x18c0, 0x1980, 0xd941, 0x1b00, 0xdbc1, 0xda81, 0x1a40, 
    0x1e00, 0xdec1, 0xdf81, 0x1f40, 0xdd01, 0x1dc0, 0x1c80, 0xdc41, 
    0x1400, 0xd4c1, 0xd581, 0x1540, 0xd701, 0x17c0, 0x1680, 0xd641, 
    0xd201, 0x12c0, 0x1380, 0xd341, 0x1100, 0xd1c1, 0xd081, 0x1040, 
    0xf001, 0x30c0, 0x3180, 0xf141, 0x3300, 0xf3c1, 0xf281, 0x3240, 
    0x3600, 0xf6c1, 0xf781, 0x3740, 0xf501, 0x35c0, 0x3480, 0xf441, 
    0x3c00, 0xfcc1, 0xfd81, 0x3d40, 0xff01, 0x3fc0, 0x3e80, 0xfe41, 
    0xfa01, 0x3ac0, 0x3b80, 0xfb41, 0x3900, 0xf9c1, 0xf881, 0x3840, 
    0x2800, 0xe8c1, 0xe981, 0x2940, 0xeb01, 0x2bc0, 0x2a80, 0xea41, 
    0xee01, 0x2ec0, 0x2f80, 0xef41, 0x2d00, 0xedc1, 0xec81, 0x2c40, 
    0xe401, 0x24c0, 0x2580, 0xe541, 0x2700, 0xe7c1, 0xe681, 0x2640, 
    0x2200, 0xe2c1, 0xe381, 0x2340, 0xe101, 0x21c0, 0x2080, 0xe041, 
    0xa001, 0x60c0, 0x6180, 0xa141, 0x6300, 0xa3c1, 0xa281, 0x6240, 
    0x6600, 0xa6c1, 0xa781, 0x6740, 0xa501, 0x65c0, 0x6480, 0xa441, 
    0x6c00, 0xacc1, 0xad81, 0x6d40, 0xaf01, 0x6fc0, 0x6e80, 0xae41, 
    0xaa01, 0x6ac0, 0x6b80, 0xab41, 0x6900, 0xa9c1, 0xa881, 0x6840, 
    0x7800, 0xb8c1, 0xb981, 0x7940, 0xbb01, 0x7bc0, 0x7a80, 0xba41, 
    0xbe01, 0x7ec0, 0x7f80, 0xbf41, 0x7d00, 0xbdc1, 0xbc81, 0x7c40, 
    0xb401, 0x74c0, 0x7580, 0xb541, 0x7700, 0xb7c1, 0xb681, 0x7640, 
    0x7200, 0xb2c1, 0xb381, 0x7340, 0xb101, 0x71c0, 0x7080, 0xb041, 
    0x5000, 0x90c1, 0x9181, 0x5140, 0x9301, 0x53c0, 0x5280, 0x9241, 
    0x9601, 0x56c0, 0x5780, 0x9741, 0x5500, 0x95c1, 0x9481, 0x5440, 
    0x9c01, 0x5cc0, 0x5d80, 0x9d41, 0x5f00, 0x9fc1, 0x9e81, 0x5e40, 
    0x5a00, 0x9ac1, 0x9b81, 0x5b40, 0x9901, 0x59c0, 0x5880, 0x9841, 
    0x8801, 0x48c0, 0x4980, 0x8941, 0x4b00, 0x8bc1, 0x8a81, 0x4a40, 
    0x4e00, 0x8ec1, 0x8f81, 0x4f40, 0x8d01, 0x4dc0, 0x4c80, 0x8c41, 
    0x4400, 0x84c1, 0x8581, 0x4540, 0x8701, 0x47c0, 0x4680, 0x8641, 
    0x8201, 0x42c0, 0x4380, 0x8341, 0x4100, 0x81c1, 0x8081, 0x4040]

def crc16_modbus(init_crc, dat, len):
    crc = [init_crc &gt;&gt; 8, init_crc &amp; 0xFF]    
    for b in dat:
        tmp = crc16_table[crc[0] ^ b]
        crc[0] = (tmp &amp; 0xFF) ^ crc[1]
        crc[1] = tmp&gt;&gt;8
    
    return (crc[0]|crc[1]&lt;&lt;8)</p>
                                </div><div id="SE-1177bde0-2b74-4e50-b2f3-8bc007ba0423">
                                    <p>dat = bytes([0x11, 0x22, 0x33, 0x44, 0x55])
crc = hex(crc16_modbus(0xFFFF, dat, len(dat)))
print(f'crc-16/modbus : {crc}')</p>
                                </div><div id="SE-70380bef-79a1-4cda-9b2a-be834821b9a4">
                                    <p id="SE-1cb6bc2c-016d-4dfd-b962-bb91b95597a0"><span id="SE-098b5623-c36d-44f9-b297-24e7f2f976a6">​</span></p><p id="SE-5514e7bf-5847-452f-9f83-a668cdd6dbb2"><span id="SE-4d921ac8-d0d4-49b1-80aa-594fc0b4efb6">아래의 코드는 위와 동일한 기능을 C언어로 작성한 것이다.</span></p>
                            </div><div id="SE-8130f2e5-d826-4947-8c90-db4ca4e3e7ed">
                                    <p>static uint16_t crc_16_table[] = {
    0x0000, 0xc0c1, 0xc181, 0x0140, 0xc301, 0x03c0, 0x0280, 0xc241,
    0xc601, 0x06c0, 0x0780, 0xc741, 0x0500, 0xc5c1, 0xc481, 0x0440,
    0xcc01, 0x0cc0, 0x0d80, 0xcd41, 0x0f00, 0xcfc1, 0xce81, 0x0e40,
    0x0a00, 0xcac1, 0xcb81, 0x0b40, 0xc901, 0x09c0, 0x0880, 0xc841,
    0xd801, 0x18c0, 0x1980, 0xd941, 0x1b00, 0xdbc1, 0xda81, 0x1a40,
    0x1e00, 0xdec1, 0xdf81, 0x1f40, 0xdd01, 0x1dc0, 0x1c80, 0xdc41,
    0x1400, 0xd4c1, 0xd581, 0x1540, 0xd701, 0x17c0, 0x1680, 0xd641,
    0xd201, 0x12c0, 0x1380, 0xd341, 0x1100, 0xd1c1, 0xd081, 0x1040,
    0xf001, 0x30c0, 0x3180, 0xf141, 0x3300, 0xf3c1, 0xf281, 0x3240,
    0x3600, 0xf6c1, 0xf781, 0x3740, 0xf501, 0x35c0, 0x3480, 0xf441,
    0x3c00, 0xfcc1, 0xfd81, 0x3d40, 0xff01, 0x3fc0, 0x3e80, 0xfe41,
    0xfa01, 0x3ac0, 0x3b80, 0xfb41, 0x3900, 0xf9c1, 0xf881, 0x3840,
    0x2800, 0xe8c1, 0xe981, 0x2940, 0xeb01, 0x2bc0, 0x2a80, 0xea41,
    0xee01, 0x2ec0, 0x2f80, 0xef41, 0x2d00, 0xedc1, 0xec81, 0x2c40,
    0xe401, 0x24c0, 0x2580, 0xe541, 0x2700, 0xe7c1, 0xe681, 0x2640,
    0x2200, 0xe2c1, 0xe381, 0x2340, 0xe101, 0x21c0, 0x2080, 0xe041,
    0xa001, 0x60c0, 0x6180, 0xa141, 0x6300, 0xa3c1, 0xa281, 0x6240,
    0x6600, 0xa6c1, 0xa781, 0x6740, 0xa501, 0x65c0, 0x6480, 0xa441,
    0x6c00, 0xacc1, 0xad81, 0x6d40, 0xaf01, 0x6fc0, 0x6e80, 0xae41,
    0xaa01, 0x6ac0, 0x6b80, 0xab41, 0x6900, 0xa9c1, 0xa881, 0x6840,
    0x7800, 0xb8c1, 0xb981, 0x7940, 0xbb01, 0x7bc0, 0x7a80, 0xba41,
    0xbe01, 0x7ec0, 0x7f80, 0xbf41, 0x7d00, 0xbdc1, 0xbc81, 0x7c40,
    0xb401, 0x74c0, 0x7580, 0xb541, 0x7700, 0xb7c1, 0xb681, 0x7640,
    0x7200, 0xb2c1, 0xb381, 0x7340, 0xb101, 0x71c0, 0x7080, 0xb041,
    0x5000, 0x90c1, 0x9181, 0x5140, 0x9301, 0x53c0, 0x5280, 0x9241,
    0x9601, 0x56c0, 0x5780, 0x9741, 0x5500, 0x95c1, 0x9481, 0x5440,
    0x9c01, 0x5cc0, 0x5d80, 0x9d41, 0x5f00, 0x9fc1, 0x9e81, 0x5e40,
    0x5a00, 0x9ac1, 0x9b81, 0x5b40, 0x9901, 0x59c0, 0x5880, 0x9841,
    0x8801, 0x48c0, 0x4980, 0x8941, 0x4b00, 0x8bc1, 0x8a81, 0x4a40,
    0x4e00, 0x8ec1, 0x8f81, 0x4f40, 0x8d01, 0x4dc0, 0x4c80, 0x8c41,
    0x4400, 0x84c1, 0x8581, 0x4540, 0x8701, 0x47c0, 0x4680, 0x8641,
    0x8201, 0x42c0, 0x4380, 0x8341, 0x4100, 0x81c1, 0x8081, 0x4040
};

uint16_t crc16_modbus(uint16_t init_crc, uint8_t* dat, uint16_t len) {
    uint8_t crc[2];
    uint16_t tmp;
    crc[0] = init_crc &gt;&gt; 8;
    crc[1] = init_crc &amp; 0xFF;
    for (uint16_t i = 0; i &lt; len; i++) {
        tmp = crc_16_table[crc[0] ^ dat[i]];
        crc[0] = (tmp &amp; 0xFF) ^ crc[1];
        crc[1] = tmp &gt;&gt; 8;
    }
    return crc[0] | ((uint16_t)crc[1] &lt;&lt; 8);
}</p>
                                </div><div id="SE-961fd527-cf1e-4549-94ed-b3dd35429b25">
                                    <p>uint8_t dat[] = { 0x11, 0x22, 0x33, 0x44, 0x55 };
uint16_t crc = crc16_modbus(0xFFFF, dat, sizeof(dat));
printf("crc-16/modbus : 0x%04X\n", crc);  </p>
                                </div><div id="SE-c325df18-d5ec-4ed1-aa7b-79b040d19a9f">
                            <p id="SE-7a1f96af-a846-4a41-961b-ed02c3b81875"><span id="SE-0cfadb1f-2af1-4e3e-a1d5-eaac0be098fe">C 코드 테스트는 Visual Studio로!!</span></p>
                        </div></div>

하이! 제니스

이전에 CRC-8/MAXIM 을 구현해 봤고 이번엔 CRC-16/MODBUS를 파이썬과 C로 작성해 봤다. 사용 방법은 다음과 같다. 아래의 코드는 위와 동일한 기능을 C언어로 작성한 것이다. C 코드 테스트는 Visual Studio로!!

파이썬 - CRC-16/Modbus 구현하기 그리고 C 언어로 구현

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