分类: 嵌入式
2010-05-20 01:31:40
0
#define SOH 0x01 #define STX 0x02 #define EOT 0x04 #define ACK 0x06 #define NAK 0x15 #define CAN 0x18 #define CTRLZ 0x1A #define DLY_1S 1000 #define MAXRETRANS 25 static int last_error = 0; #i nclude "string.h" void port_outbyte(unsigned char trychar) { unsigned char buf[2]; buf[0] = trychar; lowLevel_write(buf,1); } unsigned char port_inbyte(unsigned int time_out) { unsigned char ch; int i; last_error = 0; if(lowLevel_read(&ch,1) == 1) return ch; last_error = 1; return ch; } static int check(int crc, const unsigned char *buf, int sz) { if (crc) { unsigned short crc = crc16_ccitt(buf, sz); unsigned short tcrc = (buf[sz]<<8)+buf[sz+1]; if (crc == tcrc) return 1; } else { int i; unsigned char cks = 0; for (i = 0; i < sz; ++i) { cks += buf[i]; } if (cks == buf[sz]) return 1; } return 0; } static void flushinput(void) { //while (port_inbyte(((DLY_1S)*3)>>1) >= 0) ; } int xmodemReceive(unsigned char *dest, int destsz) { unsigned char xbuff[1030]; unsigned char *p; int bufsz, crc = 0; unsigned char trychar = 'C'; unsigned char packetno = 1; int i, c, len = 0; int retry, retrans = MAXRETRANS; for(;;) { for( retry = 0; retry < 16; ++retry) { if (trychar) port_outbyte(trychar); c = port_inbyte((DLY_1S)<<1); if (last_error == 0) { switch (c) { case SOH: bufsz = 128; goto start_recv; case STX: bufsz = 1024; goto start_recv; case EOT: flushinput(); port_outbyte(ACK); return len; case CAN: c = port_inbyte(DLY_1S); if (c == CAN) { flushinput(); port_outbyte(ACK); return -1; } break; default: break; } } } if (trychar == 'C') { trychar = NAK; continue; } flushinput(); port_outbyte(CAN); port_outbyte(CAN); port_outbyte(CAN); return -2; start_recv: if (trychar == 'C') crc = 1; trychar = 0; p = xbuff; *p++ = c; for (i = 0; i < (bufsz+(crc?1:0)+3); ++i) { c = port_inbyte(DLY_1S); if (last_error != 0) goto reject; *p++ = c; } if (xbuff[1] == (unsigned char)(~xbuff[2]) && (xbuff[1] == packetno || xbuff[1] == (unsigned char)packetno-1) && check(crc, &xbuff[3], bufsz)) { if (xbuff[1] == packetno) { int count = destsz - len; if (count > bufsz) count = bufsz; if (count > 0) { memcpy (&dest[len], &xbuff[3], count); len += count; } ++packetno; retrans = MAXRETRANS+1; } if (--retrans <= 0) { flushinput(); port_outbyte(CAN); port_outbyte(CAN); port_outbyte(CAN); return -3; } port_outbyte(ACK); continue; } reject: flushinput(); port_outbyte(NAK); } } int xmodemTransmit(unsigned char *src, int srcsz) { unsigned char xbuff[1030]; int bufsz, crc = -1; unsigned char packetno = 1; int i, c, len = 0; int retry; for(;;) { for( retry = 0; retry < 16; ++retry) { c = port_inbyte((DLY_1S)<<1); if (last_error == 0) { switch (c) { case 'C': crc = 1; goto start_trans; case NAK: crc = 0; goto start_trans; case CAN: c = port_inbyte(DLY_1S); if (c == CAN) { port_outbyte(ACK); flushinput(); return -1; } break; default: break; } } } port_outbyte(CAN); port_outbyte(CAN); port_outbyte(CAN); flushinput(); return -2; for(;;) { start_trans: xbuff[0] = SOH; bufsz = 128; xbuff[1] = packetno; xbuff[2] = ~packetno; c = srcsz - len; if (c > bufsz) c = bufsz; if (c >= 0) { memset (&xbuff[3], 0, bufsz); if (c == 0) { xbuff[3] = CTRLZ; } else { memcpy (&xbuff[3], &src[len], c); if (c < bufsz) xbuff[3+c] = CTRLZ; } if (crc) { unsigned short ccrc = crc16_ccitt(&xbuff[3], bufsz); xbuff[bufsz+3] = (ccrc>>8) & 0xFF; xbuff[bufsz+4] = ccrc & 0xFF; } else { unsigned char ccks = 0; for (i = 3; i < bufsz+3; ++i) { ccks += xbuff[i]; } xbuff[bufsz+3] = ccks; } for (retry = 0; retry < MAXRETRANS; ++retry) { for (i = 0; i < bufsz+4+(crc?1:0); ++i) { port_outbyte(xbuff[i]); } c = port_inbyte(DLY_1S); if (last_error == 0 ) { switch (c) { case ACK: ++packetno; len += bufsz; goto start_trans; case CAN: c = port_inbyte(DLY_1S); if ( c == CAN) { port_outbyte(ACK); flushinput(); return -1; } break; case NAK: default: break; } } } port_outbyte(CAN); port_outbyte(CAN); port_outbyte(CAN); flushinput(); return -4; } else { for (retry = 0; retry < 10; ++retry) { port_outbyte(EOT); c = port_inbyte((DLY_1S)<<1); if (c == ACK) break; } flushinput(); return (c == ACK)?len:-5; } } } } |
0
static const unsigned short crc16tab[256]= { 0x0000,0x1021,0x2042,0x3063,0x4084,0x50a5,0x60c6,0x70e7, 0x8108,0x9129,0xa14a,0xb16b,0xc18c,0xd1ad,0xe1ce,0xf1ef, 0x1231,0x0210,0x3273,0x2252,0x52b5,0x4294,0x72f7,0x62d6, 0x9339,0x8318,0xb37b,0xa35a,0xd3bd,0xc39c,0xf3ff,0xe3de, 0x2462,0x3443,0x0420,0x1401,0x64e6,0x74c7,0x44a4,0x5485, 0xa56a,0xb54b,0x8528,0x9509,0xe5ee,0xf5cf,0xc5ac,0xd58d, 0x3653,0x2672,0x1611,0x0630,0x76d7,0x66f6,0x5695,0x46b4, 0xb75b,0xa77a,0x9719,0x8738,0xf7df,0xe7fe,0xd79d,0xc7bc, 0x48c4,0x58e5,0x6886,0x78a7,0x0840,0x1861,0x2802,0x3823, 0xc9cc,0xd9ed,0xe98e,0xf9af,0x8948,0x9969,0xa90a,0xb92b, 0x5af5,0x4ad4,0x7ab7,0x6a96,0x1a71,0x0a50,0x3a33,0x2a12, 0xdbfd,0xcbdc,0xfbbf,0xeb9e,0x9b79,0x8b58,0xbb3b,0xab1a, 0x6ca6,0x7c87,0x4ce4,0x5cc5,0x2c22,0x3c03,0x0c60,0x1c41, 0xedae,0xfd8f,0xcdec,0xddcd,0xad2a,0xbd0b,0x8d68,0x9d49, 0x7e97,0x6eb6,0x5ed5,0x4ef4,0x3e13,0x2e32,0x1e51,0x0e70, 0xff9f,0xefbe,0xdfdd,0xcffc,0xbf1b,0xaf3a,0x9f59,0x8f78, 0x9188,0x81a9,0xb1ca,0xa1eb,0xd10c,0xc12d,0xf14e,0xe16f, 0x1080,0x00a1,0x30c2,0x20e3,0x5004,0x4025,0x7046,0x6067, 0x83b9,0x9398,0xa3fb,0xb3da,0xc33d,0xd31c,0xe37f,0xf35e, 0x02b1,0x1290,0x22f3,0x32d2,0x4235,0x5214,0x6277,0x7256, 0xb5ea,0xa5cb,0x95a8,0x8589,0xf56e,0xe54f,0xd52c,0xc50d, 0x34e2,0x24c3,0x14a0,0x0481,0x7466,0x6447,0x5424,0x4405, 0xa7db,0xb7fa,0x8799,0x97b8,0xe75f,0xf77e,0xc71d,0xd73c, 0x26d3,0x36f2,0x0691,0x16b0,0x6657,0x7676,0x4615,0x5634, 0xd94c,0xc96d,0xf90e,0xe92f,0x99c8,0x89e9,0xb98a,0xa9ab, 0x5844,0x4865,0x7806,0x6827,0x18c0,0x08e1,0x3882,0x28a3, 0xcb7d,0xdb5c,0xeb3f,0xfb1e,0x8bf9,0x9bd8,0xabbb,0xbb9a, 0x4a75,0x5a54,0x6a37,0x7a16,0x0af1,0x1ad0,0x2ab3,0x3a92, 0xfd2e,0xed0f,0xdd6c,0xcd4d,0xbdaa,0xad8b,0x9de8,0x8dc9, 0x7c26,0x6c07,0x5c64,0x4c45,0x3ca2,0x2c83,0x1ce0,0x0cc1, 0xef1f,0xff3e,0xcf5d,0xdf7c,0xaf9b,0xbfba,0x8fd9,0x9ff8, 0x6e17,0x7e36,0x4e55,0x5e74,0x2e93,0x3eb2,0x0ed1,0x1ef0 }; unsigned short crc16_ccitt(const char *buf, int len) { register int counter; register unsigned short crc = 0; for( counter = 0; counter < len; counter++) crc = (crc<<8) ^ crc16tab[((crc>>8) ^ *(char *)buf++)&0x00FF]; return crc; } |