Paul van der Wielen
1-Wire implementation, using DS2480B controller interfaced with serial port, working example to read DS18B20, based on work already in progress / Dallas - Public domain code
crcutil.cpp@0:1193dbfe28e2, 2011-03-24 (annotated)
- Committer:
- pwheels
- Date:
- Thu Mar 24 17:21:29 2011 +0000
- Revision:
- 0:1193dbfe28e2
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| pwheels | 0:1193dbfe28e2 | 1 | //--------------------------------------------------------------------------- |
| pwheels | 0:1193dbfe28e2 | 2 | // Copyright (C) 2000 Dallas Semiconductor Corporation, All Rights Reserved. |
| pwheels | 0:1193dbfe28e2 | 3 | // |
| pwheels | 0:1193dbfe28e2 | 4 | // Permission is hereby granted, free of charge, to any person obtaining a |
| pwheels | 0:1193dbfe28e2 | 5 | // copy of this software and associated documentation files (the "Software"), |
| pwheels | 0:1193dbfe28e2 | 6 | // to deal in the Software without restriction, including without limitation |
| pwheels | 0:1193dbfe28e2 | 7 | // the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| pwheels | 0:1193dbfe28e2 | 8 | // and/or sell copies of the Software, and to permit persons to whom the |
| pwheels | 0:1193dbfe28e2 | 9 | // Software is furnished to do so, subject to the following conditions: |
| pwheels | 0:1193dbfe28e2 | 10 | // |
| pwheels | 0:1193dbfe28e2 | 11 | // The above copyright notice and this permission notice shall be included |
| pwheels | 0:1193dbfe28e2 | 12 | // in all copies or substantial portions of the Software. |
| pwheels | 0:1193dbfe28e2 | 13 | // |
| pwheels | 0:1193dbfe28e2 | 14 | // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS |
| pwheels | 0:1193dbfe28e2 | 15 | // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| pwheels | 0:1193dbfe28e2 | 16 | // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| pwheels | 0:1193dbfe28e2 | 17 | // IN NO EVENT SHALL DALLAS SEMICONDUCTOR BE LIABLE FOR ANY CLAIM, DAMAGES |
| pwheels | 0:1193dbfe28e2 | 18 | // OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, |
| pwheels | 0:1193dbfe28e2 | 19 | // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR |
| pwheels | 0:1193dbfe28e2 | 20 | // OTHER DEALINGS IN THE SOFTWARE. |
| pwheels | 0:1193dbfe28e2 | 21 | // |
| pwheels | 0:1193dbfe28e2 | 22 | // Except as contained in this notice, the name of Dallas Semiconductor |
| pwheels | 0:1193dbfe28e2 | 23 | // shall not be used except as stated in the Dallas Semiconductor |
| pwheels | 0:1193dbfe28e2 | 24 | // Branding Policy. |
| pwheels | 0:1193dbfe28e2 | 25 | //-------------------------------------------------------------------------- |
| pwheels | 0:1193dbfe28e2 | 26 | // |
| pwheels | 0:1193dbfe28e2 | 27 | // crcutil.c - Keeps track of the CRC for 16 and 8 bit operations |
| pwheels | 0:1193dbfe28e2 | 28 | // version 2.00 |
| pwheels | 0:1193dbfe28e2 | 29 | |
| pwheels | 0:1193dbfe28e2 | 30 | // Include files |
| pwheels | 0:1193dbfe28e2 | 31 | #include "ownet.h" |
| pwheels | 0:1193dbfe28e2 | 32 | |
| pwheels | 0:1193dbfe28e2 | 33 | // Local global variables |
| pwheels | 0:1193dbfe28e2 | 34 | unsigned short utilcrc16[MAX_PORTNUM]; |
| pwheels | 0:1193dbfe28e2 | 35 | uchar utilcrc8[MAX_PORTNUM]; |
| pwheels | 0:1193dbfe28e2 | 36 | static short oddparity[16] = { 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 }; |
| pwheels | 0:1193dbfe28e2 | 37 | static uchar dscrc_table[] = { |
| pwheels | 0:1193dbfe28e2 | 38 | 0, 94,188,226, 97, 63,221,131,194,156,126, 32,163,253, 31, 65, |
| pwheels | 0:1193dbfe28e2 | 39 | 157,195, 33,127,252,162, 64, 30, 95, 1,227,189, 62, 96,130,220, |
| pwheels | 0:1193dbfe28e2 | 40 | 35,125,159,193, 66, 28,254,160,225,191, 93, 3,128,222, 60, 98, |
| pwheels | 0:1193dbfe28e2 | 41 | 190,224, 2, 92,223,129, 99, 61,124, 34,192,158, 29, 67,161,255, |
| pwheels | 0:1193dbfe28e2 | 42 | 70, 24,250,164, 39,121,155,197,132,218, 56,102,229,187, 89, 7, |
| pwheels | 0:1193dbfe28e2 | 43 | 219,133,103, 57,186,228, 6, 88, 25, 71,165,251,120, 38,196,154, |
| pwheels | 0:1193dbfe28e2 | 44 | 101, 59,217,135, 4, 90,184,230,167,249, 27, 69,198,152,122, 36, |
| pwheels | 0:1193dbfe28e2 | 45 | 248,166, 68, 26,153,199, 37,123, 58,100,134,216, 91, 5,231,185, |
| pwheels | 0:1193dbfe28e2 | 46 | 140,210, 48,110,237,179, 81, 15, 78, 16,242,172, 47,113,147,205, |
| pwheels | 0:1193dbfe28e2 | 47 | 17, 79,173,243,112, 46,204,146,211,141,111, 49,178,236, 14, 80, |
| pwheels | 0:1193dbfe28e2 | 48 | 175,241, 19, 77,206,144,114, 44,109, 51,209,143, 12, 82,176,238, |
| pwheels | 0:1193dbfe28e2 | 49 | 50,108,142,208, 83, 13,239,177,240,174, 76, 18,145,207, 45,115, |
| pwheels | 0:1193dbfe28e2 | 50 | 202,148,118, 40,171,245, 23, 73, 8, 86,180,234,105, 55,213,139, |
| pwheels | 0:1193dbfe28e2 | 51 | 87, 9,235,181, 54,104,138,212,149,203, 41,119,244,170, 72, 22, |
| pwheels | 0:1193dbfe28e2 | 52 | 233,183, 85, 11,136,214, 52,106, 43,117,151,201, 74, 20,246,168, |
| pwheels | 0:1193dbfe28e2 | 53 | 116, 42,200,150, 21, 75,169,247,182,232, 10, 84,215,137,107, 53}; |
| pwheels | 0:1193dbfe28e2 | 54 | |
| pwheels | 0:1193dbfe28e2 | 55 | //-------------------------------------------------------------------------- |
| pwheels | 0:1193dbfe28e2 | 56 | // Reset crc16 to the value passed in |
| pwheels | 0:1193dbfe28e2 | 57 | // |
| pwheels | 0:1193dbfe28e2 | 58 | // 'reset' - data to set crc16 to. |
| pwheels | 0:1193dbfe28e2 | 59 | // |
| pwheels | 0:1193dbfe28e2 | 60 | void setcrc16(int portnum, unsigned short reset) |
| pwheels | 0:1193dbfe28e2 | 61 | { |
| pwheels | 0:1193dbfe28e2 | 62 | utilcrc16[portnum&0x0FF] = reset; |
| pwheels | 0:1193dbfe28e2 | 63 | return; |
| pwheels | 0:1193dbfe28e2 | 64 | } |
| pwheels | 0:1193dbfe28e2 | 65 | |
| pwheels | 0:1193dbfe28e2 | 66 | //-------------------------------------------------------------------------- |
| pwheels | 0:1193dbfe28e2 | 67 | // Reset crc8 to the value passed in |
| pwheels | 0:1193dbfe28e2 | 68 | // |
| pwheels | 0:1193dbfe28e2 | 69 | // 'portnum' - number 0 to MAX_PORTNUM-1. This number is provided to |
| pwheels | 0:1193dbfe28e2 | 70 | // indicate the symbolic port number. |
| pwheels | 0:1193dbfe28e2 | 71 | // 'reset' - data to set crc8 to |
| pwheels | 0:1193dbfe28e2 | 72 | // |
| pwheels | 0:1193dbfe28e2 | 73 | void setcrc8(int portnum, uchar reset) |
| pwheels | 0:1193dbfe28e2 | 74 | { |
| pwheels | 0:1193dbfe28e2 | 75 | utilcrc8[portnum&0x0FF] = reset; |
| pwheels | 0:1193dbfe28e2 | 76 | return; |
| pwheels | 0:1193dbfe28e2 | 77 | } |
| pwheels | 0:1193dbfe28e2 | 78 | |
| pwheels | 0:1193dbfe28e2 | 79 | //-------------------------------------------------------------------------- |
| pwheels | 0:1193dbfe28e2 | 80 | // Calculate a new CRC16 from the input data short. Return the current |
| pwheels | 0:1193dbfe28e2 | 81 | // CRC16 and also update the global variable CRC16. |
| pwheels | 0:1193dbfe28e2 | 82 | // |
| pwheels | 0:1193dbfe28e2 | 83 | // 'portnum' - number 0 to MAX_PORTNUM-1. This number is provided to |
| pwheels | 0:1193dbfe28e2 | 84 | // indicate the symbolic port number. |
| pwheels | 0:1193dbfe28e2 | 85 | // 'data' - data to perform a CRC16 on |
| pwheels | 0:1193dbfe28e2 | 86 | // |
| pwheels | 0:1193dbfe28e2 | 87 | // Returns: the current CRC16 |
| pwheels | 0:1193dbfe28e2 | 88 | // |
| pwheels | 0:1193dbfe28e2 | 89 | unsigned short docrc16(int portnum, unsigned short cdata) |
| pwheels | 0:1193dbfe28e2 | 90 | { |
| pwheels | 0:1193dbfe28e2 | 91 | cdata = (cdata ^ (utilcrc16[portnum&0x0FF] & 0xff)) & 0xff; |
| pwheels | 0:1193dbfe28e2 | 92 | utilcrc16[portnum&0x0FF] >>= 8; |
| pwheels | 0:1193dbfe28e2 | 93 | |
| pwheels | 0:1193dbfe28e2 | 94 | if (oddparity[cdata & 0xf] ^ oddparity[cdata >> 4]) |
| pwheels | 0:1193dbfe28e2 | 95 | utilcrc16[portnum&0x0FF] ^= 0xc001; |
| pwheels | 0:1193dbfe28e2 | 96 | |
| pwheels | 0:1193dbfe28e2 | 97 | cdata <<= 6; |
| pwheels | 0:1193dbfe28e2 | 98 | utilcrc16[portnum&0x0FF] ^= cdata; |
| pwheels | 0:1193dbfe28e2 | 99 | cdata <<= 1; |
| pwheels | 0:1193dbfe28e2 | 100 | utilcrc16[portnum&0x0FF] ^= cdata; |
| pwheels | 0:1193dbfe28e2 | 101 | |
| pwheels | 0:1193dbfe28e2 | 102 | return utilcrc16[portnum&0x0FF]; |
| pwheels | 0:1193dbfe28e2 | 103 | } |
| pwheels | 0:1193dbfe28e2 | 104 | |
| pwheels | 0:1193dbfe28e2 | 105 | //-------------------------------------------------------------------------- |
| pwheels | 0:1193dbfe28e2 | 106 | // Update the Dallas Semiconductor One Wire CRC (utilcrc8) from the global |
| pwheels | 0:1193dbfe28e2 | 107 | // variable utilcrc8 and the argument. |
| pwheels | 0:1193dbfe28e2 | 108 | // |
| pwheels | 0:1193dbfe28e2 | 109 | // 'portnum' - number 0 to MAX_PORTNUM-1. This number is provided to |
| pwheels | 0:1193dbfe28e2 | 110 | // indicate the symbolic port number. |
| pwheels | 0:1193dbfe28e2 | 111 | // 'x' - data byte to calculate the 8 bit crc from |
| pwheels | 0:1193dbfe28e2 | 112 | // |
| pwheels | 0:1193dbfe28e2 | 113 | // Returns: the updated utilcrc8. |
| pwheels | 0:1193dbfe28e2 | 114 | // |
| pwheels | 0:1193dbfe28e2 | 115 | uchar docrc8(int portnum, uchar x) |
| pwheels | 0:1193dbfe28e2 | 116 | { |
| pwheels | 0:1193dbfe28e2 | 117 | utilcrc8[portnum&0x0FF] = dscrc_table[utilcrc8[portnum&0x0FF] ^ x]; |
| pwheels | 0:1193dbfe28e2 | 118 | return utilcrc8[portnum&0x0FF]; |
| pwheels | 0:1193dbfe28e2 | 119 | } |