Linear Technology LTC6804-1, Руководство пользователя

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LTC6804-1/LTC6804-2
65
680412fc
For more information www.linear.com/LTC6804-1
applicaTions inForMaTion
/************************************
Copyright 2012 Linear Technology Corp. (LTC)
Permission to freely use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies:
THIS SOFTWARE IS PROVIDED “AS IS” AND LTC DISCLAIMS ALL WARRANTIES
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
EVENT SHALL LTC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM ANY USE OF SAME, INCLUDING
ANY LOSS OF USE OR DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
OR OTHER TORTUOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.
***********************************************************/
int16 pec15Table[256];
int16 CRC15_POLY = 0x4599;
void init_PEC15_Table()
{
for (int i = 0; i < 256; i++)
{
remainder = i << 7;
for (int bit = 8; bit > 0; --bit)
{
if (remainder & 0x4000)
{
remainder = ((remainder << 1));
remainder = (remainder ^ CRC15poly)
}
else
{
remainder = ((remainder << 1));
}
}
pec15Table[i] = remainder&0xFFFF;
}
}
unsigned int16 pec15 (char *data , int len)
{
int16 remainder,address;
remainder = 16;//PEC seed
for (int i = 0; i < len; i++)
{
address = ((remainder >> 7) ^ data[i]) & 0xff;//calculate PEC table address
remainder = (remainder << 8 ) ^ pec15Table[address];
}
return (remainder*2);//The CRC15 has a 0 in the LSB so the final value must be multiplied by 2
}