int protocol_get_buffer(char *dst, int max_len)
{
uint16_t crc16;
uint16_t packet_crc16;
int cpy_len = protocol_buffer_p;
if (cpy_len>max_len) cpy_len = max_len;
if (!cpy_len) return 0;
/*crc takes 2 bytes*/
if (cpy_len<2) return ERR_BAD_LEN;
crc16 = crc16_calc (protocol_buffer,cpy_len-2 );
packet_crc16 = protocol_buffer[cpy_len-2];
packet_crc16 = packet_crc16<<8;
packet_crc16 |= protocol_buffer[cpy_len-1];
/* 0xBEEF is used for DEBUG CRC*/
if (packet_crc16!=0xBEEF && (packet_crc16!=crc16))
{
protocol_buffer_clr();
return ERR_BAD_CRC;
}
memcpy(dst,protocol_buffer,cpy_len-2);
protocol_buffer_clr();
return cpy_len-2;
}
// <0 for failure, 1 for file done, 0 for OK to send
_xmodem_debug
int _assemble_packet( xbee_xmodem_state_t *xbxm, uint16_t block_size)
{
int err;
uint8_t packet_num;
uint16_t checksum;
int ch;
uint16_t i;
char FAR *p;
// Assemble a packet to send -- 3-byte header; 64, 128 or 1K xmodem
// block from source file; and then 1-byte checksum or 2-byte CRC.
xbxm->tries = 3;
xbxm->buffer[0] =
(xbxm->flags & XBEE_XMODEM_FLAG_1K) ? XMODEM_STX : XMODEM_SOH;
packet_num = (uint8_t) xbxm->packet_num;
xbxm->buffer[1] = packet_num;
xbxm->buffer[2] = ~packet_num;
err = xbxm->file.read( xbxm->file.context, &xbxm->buffer[3], block_size);
if (err == -ENODATA || err == 0)
{
#ifdef XBEE_XMODEM_VERBOSE
printf( "%s: reached end of file\n", __FUNCTION__);
#endif
xbxm->state = XBEE_XMODEM_STATE_EOF;
return 1;
}
else if (err < 0)
{
#ifdef XBEE_XMODEM_VERBOSE
printf( "%s: error %d reading file\n", __FUNCTION__, err);
#endif
return err;
}
else if (err < block_size)
{
// if necessary, we could wrap this all up into a while loop that
// uses multiple reads, if necessary, to fill xbxm->buffer.
if (xbxm->file.read( xbxm->file.context, &ch, 1) == 1)
{
#ifdef XBEE_XMODEM_VERBOSE
printf( "%s: short read of %d bytes\n", __FUNCTION__, err);
#endif
return -EIO;
}
// short read, but it's the last block from the file -- set
// remaining bytes to 0xFF
_f_memset( &xbxm->buffer[3 + err], 0xFF, block_size - err);
}
if (xbxm->flags & XBEE_XMODEM_FLAG_CRC)
{
checksum = crc16_calc( &xbxm->buffer[3], block_size, 0);
// append 16-bit CRC, MSB-first
xbxm->buffer[3 + block_size] = checksum >> 8;
xbxm->buffer[4 + block_size] = checksum & 0x00FF;
}
void protocol_send_buffer(unsigned char *src, int len)
{
uint16_t crc16;
crc16 = crc16_calc(src,len);
uart1_putchar(STX);
while(len--)
protocol_send_char(*src++);
protocol_send_char(crc16>>8);
protocol_send_char(crc16&0xff);
uart1_putchar(ETX);
}
uint16_t crc16_ccitt(uint8_t *message, int nBytes) {
return crc16_calc(message, nBytes, POLYNOMIAL_CRC15_CCIT);
}
uint16_t crc16_ansi(uint8_t *message, int nBytes) {
return crc16_calc(message, nBytes, POLYNOMIAL_CRC15_ANSI);
}
