Team Fox / Mbed 2 deprecated QM_BAE_review_1_EPS_updated

Updated EPS code with flowchart v2.3 (CDMS and HW faults)

Dependencies:   FreescaleIAP mbed-rtos mbed

Fork of QM_BAE_review_1_EPS_faults by Mohamed Azad

crc.h@17:bb0d64656ba1, 2016-06-23 (annotated)

Committer:
azaddevarm
Date:
Thu Jun 23 12:14:28 2016 +0000
Revision:
17:bb0d64656ba1
Parent:
3:07e15677a75c 
Updated EPS code with flowchart v2.3

Who changed what in which revision?

UserRevisionLine numberNew contents of line
sakthipriya 3:07e15677a75c 1 //EDITS
sakthipriya 3:07e15677a75c 2 //changed the initial remainder from 0x0000 to 0xffff according to the standards
sakthipriya 3:07e15677a75c 3 //made two seperate functions crc16_gen and crc8_gen
sakthipriya 3:07e15677a75c 4
sakthipriya 3:07e15677a75c 5 #define TOPBIT16 (1 << 15)
sakthipriya 3:07e15677a75c 6 #define TOPBIT8 (1 << 7)
sakthipriya 3:07e15677a75c 7 #define POLYNOMIAL16 0x1021
sakthipriya 3:07e15677a75c 8 #define POLYNOMIAL8 0xEA
sakthipriya 3:07e15677a75c 9
sakthipriya 3:07e15677a75c 10 namespace CRC{
sakthipriya 3:07e15677a75c 11 typedef uint16_t crctype16;
sakthipriya 3:07e15677a75c 12 crctype16 crc16_gen(const unsigned char message[], unsigned int nBytes){
sakthipriya 3:07e15677a75c 13 crctype16 remainder = 0xffff;
sakthipriya 3:07e15677a75c 14 int byte;
sakthipriya 3:07e15677a75c 15 char bit;
sakthipriya 3:07e15677a75c 16
sakthipriya 3:07e15677a75c 17 for( byte = 0 ; byte < nBytes ; byte++ ){
sakthipriya 3:07e15677a75c 18 /*
sakthipriya 3:07e15677a75c 19 Bring the data byte by byte
sakthipriya 3:07e15677a75c 20 each time only one byte is brought
sakthipriya 3:07e15677a75c 21 0 xor x = x
sakthipriya 3:07e15677a75c 22 */
sakthipriya 3:07e15677a75c 23 remainder = remainder ^ ( message[byte] << 8 );
sakthipriya 3:07e15677a75c 24
sakthipriya 3:07e15677a75c 25 for( bit = 8 ; bit > 0 ; bit--){
sakthipriya 3:07e15677a75c 26 /*
sakthipriya 3:07e15677a75c 27 for each bit, xor the remainder with polynomial
sakthipriya 3:07e15677a75c 28 if the MSB is 1
sakthipriya 3:07e15677a75c 29 */
sakthipriya 3:07e15677a75c 30 if(remainder & TOPBIT16){
sakthipriya 3:07e15677a75c 31 remainder = (remainder << 1) ^ POLYNOMIAL16;
sakthipriya 3:07e15677a75c 32 /*
sakthipriya 3:07e15677a75c 33 each time the remainder is xor-ed with polynomial, the MSB is made zero
sakthipriya 3:07e15677a75c 34 hence the first digit of the remainder is ignored in the loop
sakthipriya 3:07e15677a75c 35 */
sakthipriya 3:07e15677a75c 36 }
sakthipriya 3:07e15677a75c 37 else{
sakthipriya 3:07e15677a75c 38 remainder = (remainder << 1);
sakthipriya 3:07e15677a75c 39 }
sakthipriya 3:07e15677a75c 40 }
sakthipriya 3:07e15677a75c 41 }
sakthipriya 3:07e15677a75c 42
sakthipriya 3:07e15677a75c 43 return remainder;
sakthipriya 3:07e15677a75c 44 }
sakthipriya 3:07e15677a75c 45
sakthipriya 3:07e15677a75c 46 typedef uint8_t crctype8;
sakthipriya 3:07e15677a75c 47 crctype8 crc8_gen(const unsigned char message[], unsigned int nBytes){
sakthipriya 3:07e15677a75c 48
sakthipriya 3:07e15677a75c 49 crctype8 remainder = 0xff;
sakthipriya 3:07e15677a75c 50
sakthipriya 3:07e15677a75c 51 for(int byte = 0 ; byte < nBytes ; byte++ ){
sakthipriya 3:07e15677a75c 52 /*
sakthipriya 3:07e15677a75c 53 Bring the data byte by byte
sakthipriya 3:07e15677a75c 54 each time only one byte is brought
sakthipriya 3:07e15677a75c 55 0 xor x = x
sakthipriya 3:07e15677a75c 56 */
sakthipriya 3:07e15677a75c 57 remainder = remainder ^ ( message[byte] );
sakthipriya 3:07e15677a75c 58
sakthipriya 3:07e15677a75c 59 for(int bit = 8 ; bit > 0 ; bit--){
sakthipriya 3:07e15677a75c 60 /*
sakthipriya 3:07e15677a75c 61 for each bit, xor the remainder with polynomial
sakthipriya 3:07e15677a75c 62 if the MSB is 1
sakthipriya 3:07e15677a75c 63 */
sakthipriya 3:07e15677a75c 64 if(remainder & TOPBIT8){
sakthipriya 3:07e15677a75c 65 remainder = (remainder << 1) ^ POLYNOMIAL8;
sakthipriya 3:07e15677a75c 66 /*
sakthipriya 3:07e15677a75c 67 each time the remainder is xor-ed with polynomial, the MSB is made zero
sakthipriya 3:07e15677a75c 68 hence the first digit of the remainder is ignored in the loop
sakthipriya 3:07e15677a75c 69 */
sakthipriya 3:07e15677a75c 70 }
sakthipriya 3:07e15677a75c 71 else{
sakthipriya 3:07e15677a75c 72 remainder = (remainder << 1);
sakthipriya 3:07e15677a75c 73 }
sakthipriya 3:07e15677a75c 74 }
sakthipriya 3:07e15677a75c 75 }
sakthipriya 3:07e15677a75c 76
sakthipriya 3:07e15677a75c 77 return remainder;
sakthipriya 3:07e15677a75c 78 }
sakthipriya 3:07e15677a75c 79 }