/****************************************************************************** * Name: CRC-4/ITU x4+x+1 * Poly: 0x03 * Init: 0x00 * Refin: True * Refout: True * Xorout: 0x00 * Note: *****************************************************************************/ uint8_t crc4_itu(uint8_t *data, uint_len length) { uint8_t i; uint8_t crc = 0; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; ++i) { if (crc & 1) crc = (crc >> 1) ^ 0x0C;// 0x0C = (reverse 0x03)>>(8-4) else crc = (crc >> 1); } } return crc; } /****************************************************************************** * Name: CRC-5/EPC x5+x3+1 * Poly: 0x09 * Init: 0x09 * Refin: False * Refout: False * Xorout: 0x00 * Note: *****************************************************************************/ uint8_t crc5_epc(uint8_t *data, uint_len length) { uint8_t i; uint8_t crc = 0x48; // Initial value: 0x48 = 0x09<<(8-5) while(length--) { crc ^= *data++; // crc ^= *data; data++; for ( i = 0; i < 8; i++ ) { if ( crc & 0x80 ) crc = (crc << 1) ^ 0x48; // 0x48 = 0x09<<(8-5) else crc <<= 1; } } return crc >> 3; } /****************************************************************************** * Name: CRC-5/ITU x5+x4+x2+1 * Poly: 0x15 * Init: 0x00 * Refin: True * Refout: True * Xorout: 0x00 * Note: *****************************************************************************/ uint8_t crc5_itu(uint8_t *data, uint_len length) { uint8_t i; uint8_t crc = 0; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; ++i) { if (crc & 1) crc = (crc >> 1) ^ 0x15;// 0x15 = (reverse 0x15)>>(8-5) else crc = (crc >> 1); } } return crc; } /****************************************************************************** * Name: CRC-5/USB x5+x2+1 * Poly: 0x05 * Init: 0x1F * Refin: True * Refout: True * Xorout: 0x1F * Note: *****************************************************************************/ uint8_t crc5_usb(uint8_t *data, uint_len length) { uint8_t i; uint8_t crc = 0x1F; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; ++i) { if (crc & 1) crc = (crc >> 1) ^ 0x14;// 0x14 = (reverse 0x05)>>(8-5) else crc = (crc >> 1); } } return crc ^ 0x1F; } /****************************************************************************** * Name: CRC-6/ITU x6+x+1 * Poly: 0x03 * Init: 0x00 * Refin: True * Refout: True * Xorout: 0x00 * Note: *****************************************************************************/ uint8_t crc6_itu(uint8_t *data, uint_len length) { uint8_t i; uint8_t crc = 0; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; ++i) { if (crc & 1) crc = (crc >> 1) ^ 0x30;// 0x30 = (reverse 0x03)>>(8-6) else crc = (crc >> 1); } } return crc; } /****************************************************************************** * Name: CRC-7/MMC x7+x3+1 * Poly: 0x09 * Init: 0x00 * Refin: False * Refout: False * Xorout: 0x00 * Use: MultiMediaCard,SD,ect. *****************************************************************************/ uint8_t crc7_mmc(uint8_t *data, uint_len length) { uint8_t i; uint8_t crc = 0; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for ( i = 0; i < 8; i++ ) { if ( crc & 0x80 ) crc = (crc << 1) ^ 0x12; // 0x12 = 0x09<<(8-7) else crc <<= 1; } } return crc >> 1; } /****************************************************************************** * Name: CRC-8 x8+x2+x+1 * Poly: 0x07 * Init: 0x00 * Refin: False * Refout: False * Xorout: 0x00 * Note: *****************************************************************************/ uint8_t crc8(uint8_t *data, uint_len length) { uint8_t i; uint8_t crc = 0; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for ( i = 0; i < 8; i++ ) { if ( crc & 0x80 ) crc = (crc << 1) ^ 0x07; else crc <<= 1; } } return crc; } /****************************************************************************** * Name: CRC-8/ITU x8+x2+x+1 * Poly: 0x07 * Init: 0x00 * Refin: False * Refout: False * Xorout: 0x55 * Alias: CRC-8/ATM *****************************************************************************/ uint8_t crc8_itu(uint8_t *data, uint_len length) { uint8_t i; uint8_t crc = 0; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for ( i = 0; i < 8; i++ ) { if ( crc & 0x80 ) crc = (crc << 1) ^ 0x07; else crc <<= 1; } } return crc ^ 0x55; } /****************************************************************************** * Name: CRC-8/ROHC x8+x2+x+1 * Poly: 0x07 * Init: 0xFF * Refin: True * Refout: True * Xorout: 0x00 * Note: *****************************************************************************/ uint8_t crc8_rohc(uint8_t *data, uint_len length) { uint8_t i; uint8_t crc = 0xFF; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; ++i) { if (crc & 1) crc = (crc >> 1) ^ 0xE0; // 0xE0 = reverse 0x07 else crc = (crc >> 1); } } return crc; } /****************************************************************************** * Name: CRC-8/MAXIM x8+x5+x4+1 * Poly: 0x31 * Init: 0x00 * Refin: True * Refout: True * Xorout: 0x00 * Alias: DOW-CRC,CRC-8/IBUTTON * Use: Maxim(Dallas)'s some devices,e.g. DS18B20 *****************************************************************************/ uint8_t crc8_maxim(uint8_t *data, uint_len length) { uint8_t i; uint8_t crc = 0; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; i++) { if (crc & 1) crc = (crc >> 1) ^ 0x8C; // 0x8C = reverse 0x31 else crc >>= 1; } } return crc; } /****************************************************************************** * Name: CRC-16/IBM x16+x15+x2+1 * Poly: 0x8005 * Init: 0x0000 * Refin: True * Refout: True * Xorout: 0x0000 * Alias: CRC-16,CRC-16/ARC,CRC-16/LHA *****************************************************************************/ uint16_t crc16_ibm(uint8_t *data, uint_len length) { uint8_t i; uint16_t crc = 0; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; ++i) { if (crc & 1) crc = (crc >> 1) ^ 0xA001; // 0xA001 = reverse 0x8005 else crc = (crc >> 1); } } return crc; } /****************************************************************************** * Name: CRC-16/MAXIM x16+x15+x2+1 * Poly: 0x8005 * Init: 0x0000 * Refin: True * Refout: True * Xorout: 0xFFFF * Note: *****************************************************************************/ uint16_t crc16_maxim(uint8_t *data, uint_len length) { uint8_t i; uint16_t crc = 0; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; ++i) { if (crc & 1) crc = (crc >> 1) ^ 0xA001; // 0xA001 = reverse 0x8005 else crc = (crc >> 1); } } return ~crc; // crc^0xffff } /****************************************************************************** * Name: CRC-16/USB x16+x15+x2+1 * Poly: 0x8005 * Init: 0xFFFF * Refin: True * Refout: True * Xorout: 0xFFFF * Note: *****************************************************************************/ uint16_t crc16_usb(uint8_t *data, uint_len length) { uint8_t i; uint16_t crc = 0xffff; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; ++i) { if (crc & 1) crc = (crc >> 1) ^ 0xA001; // 0xA001 = reverse 0x8005 else crc = (crc >> 1); } } return ~crc; // crc^0xffff } /****************************************************************************** * Name: CRC-16/MODBUS x16+x15+x2+1 * Poly: 0x8005 * Init: 0xFFFF * Refin: True * Refout: True * Xorout: 0x0000 * Note: *****************************************************************************/ uint16_t crc16_modbus(uint8_t *data, uint_len length) { uint8_t i; uint16_t crc = 0xffff; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; ++i) { if (crc & 1) crc = (crc >> 1) ^ 0xA001; // 0xA001 = reverse 0x8005 else crc = (crc >> 1); } } return crc; } /****************************************************************************** * Name: CRC-16/CCITT x16+x12+x5+1 * Poly: 0x1021 * Init: 0x0000 * Refin: True * Refout: True * Xorout: 0x0000 * Alias: CRC-CCITT,CRC-16/CCITT-TRUE,CRC-16/KERMIT *****************************************************************************/ uint16_t crc16_ccitt(uint8_t *data, uint_len length) { uint8_t i; uint16_t crc = 0; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; ++i) { if (crc & 1) crc = (crc >> 1) ^ 0x8408; // 0x8408 = reverse 0x1021 else crc = (crc >> 1); } } return crc; } /****************************************************************************** * Name: CRC-16/CCITT-FALSE x16+x12+x5+1 * Poly: 0x1021 * Init: 0xFFFF * Refin: False * Refout: False * Xorout: 0x0000 * Note: *****************************************************************************/ uint16_t crc16_ccitt_false(uint8_t *data, uint_len length) { uint8_t i; uint16_t crc = 0xffff; //Initial value while(length--) { crc ^= (uint16_t)(*data++) << 8; // crc ^= (uint6_t)(*data)<<8; data++; for (i = 0; i < 8; ++i) { if ( crc & 0x8000 ) crc = (crc << 1) ^ 0x1021; else crc <<= 1; } } return crc; } /****************************************************************************** * Name: CRC-16/X25 x16+x12+x5+1 * Poly: 0x1021 * Init: 0xFFFF * Refin: True * Refout: True * Xorout: 0XFFFF * Note: *****************************************************************************/ uint16_t crc16_x25(uint8_t *data, uint_len length) { uint8_t i; uint16_t crc = 0xffff; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; ++i) { if (crc & 1) crc = (crc >> 1) ^ 0x8408; // 0x8408 = reverse 0x1021 else crc = (crc >> 1); } } return ~crc; // crc^Xorout } /****************************************************************************** * Name: CRC-16/XMODEM x16+x12+x5+1 * Poly: 0x1021 * Init: 0x0000 * Refin: False * Refout: False * Xorout: 0x0000 * Alias: CRC-16/ZMODEM,CRC-16/ACORN *****************************************************************************/ uint16_t crc16_xmodem(uint8_t *data, uint_len length) { uint8_t i; uint16_t crc = 0; // Initial value while(length--) { crc ^= (uint16_t)(*data++) << 8; // crc ^= (uint16_t)(*data)<<8; data++; for (i = 0; i < 8; ++i) { if ( crc & 0x8000 ) crc = (crc << 1) ^ 0x1021; else crc <<= 1; } } return crc; } /****************************************************************************** * Name: CRC-16/DNP x16+x13+x12+x11+x10+x8+x6+x5+x2+1 * Poly: 0x3D65 * Init: 0x0000 * Refin: True * Refout: True * Xorout: 0xFFFF * Use: M-Bus,ect. *****************************************************************************/ uint16_t crc16_dnp(uint8_t *data, uint_len length) { uint8_t i; uint16_t crc = 0; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; ++i) { if (crc & 1) crc = (crc >> 1) ^ 0xA6BC; // 0xA6BC = reverse 0x3D65 else crc = (crc >> 1); } } return ~crc; // crc^Xorout } /****************************************************************************** * Name: CRC-32 x32+x26+x23+x22+x16+x12+x11+x10+x8+x7+x5+x4+x2+x+1 * Poly: 0x4C11DB7 * Init: 0xFFFFFFF * Refin: True * Refout: True * Xorout: 0xFFFFFFF * Alias: CRC_32/ADCCP * Use: WinRAR,ect. *****************************************************************************/ uint32_t crc32(uint8_t *data, uint_len length) { uint8_t i; uint32_t crc = 0xffffffff; // Initial value while(length--) { crc ^= *data++; // crc ^= *data; data++; for (i = 0; i < 8; ++i) { if (crc & 1) crc = (crc >> 1) ^ 0xEDB88320;// 0xEDB88320= reverse 0x04C11DB7 else crc = (crc >> 1); } } return ~crc; } /****************************************************************************** * Name: CRC-32/MPEG-2 x32+x26+x23+x22+x16+x12+x11+x10+x8+x7+x5+x4+x2+x+1 * Poly: 0x4C11DB7 * Init: 0xFFFFFFF * Refin: False * Refout: False * Xorout: 0x0000000 * Note: *****************************************************************************/ uint32_t crc32_mpeg_2(uint8_t *data, uint_len length) { uint8_t i; uint32_t crc = 0xffffffff; // Initial value while(length--) { crc ^= (uint32_t)(*data++) << 24;// crc ^=(uint32_t)(*data)<<24; data++; for (i = 0; i < 8; ++i) { if ( crc & 0x80000000 ) crc = (crc << 1) ^ 0x04C11DB7; else crc <<= 1; } } return crc; }
使用方法:
首先,根据输入数据长度定义合适的uint_len类型,
因为是逐位运算,所以不推荐用在实时性较高的的情况下,而且数据也不宜太长.
大多数嵌入式开发过程中需要校验的寄存器数据也不会太多.
这里使用:
typedef uint16_t uint_len;
//定义一组测试数据: uint8_t serno[] = { 0x91, 0xA3, 0xB5, 0xC7, 0x8D, 0xEB, 0x2D, 0x4E }; //输出测试数据的crc32校验码 printf("%x\n",crc32(serno, sizeof(serno))); //输出测试数据的crc8校验码 printf("%x\n",crc8(serno, sizeof(serno))); //....其它的不写了
有几个crc函数( 注意!并是不所有的)可以把校验码直接放在数据流后面一同输入,如果返回值为0,则校验通过
比如上面的serno的crc8校验码是 0X23
令
uint8_t serno2[] = { 0x91, 0xA3, 0xB5, 0xC7, 0x8D, 0xEB, 0x2D, 0x4E, 0x23 };
则执行printf("%x\n",crc8(serno2, sizeof(serno2)));
得到的输出即为0.
有的函数不为0的原因是最后一步进行了异或操作(return crc^Xorout)
其实crc校验都是一个套路,在写crc8的时候,写着写着就把所有的都写出来了.
crc64其实根据crc32也能很简单的写出来,用的不多,就不写了.