Xilinx EH600 A Series User Manual

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By using RTU frame format , the message contains error detect field that bases on . CRC field detects
the whole message data. It is two bytes and includes 16-byte binary value, it is calculated by transmission equipment and then
added to the message, the receive equipment calculates CRC over again after the message and compares it to the
received CRC value, if the two value is not the same, it indicates that the transmission is wrong.
CRC method
receiving
CRC saves to and then the continuous 8-bit byte of the message and the current
value of the . Only 8-bit data of every character is valid for CRC, the start bit the stop bit
and the odd-even check bit are all invalid. During the CRC process : every 8-bit character is single exclusive or (XOR) with
the CRC register data , the result moves to the lowest valid bit , the highest valid bit is filled with 0. LSB is distilled and
detected , if LSB is 1, the CRC register is single exclusive with preset value, if LSB is 0, nothing happens. The whole process
needs to repeat for 8 times. When the last bit finished, the next 8-bit byte character is single the CRC register
current value. The ultima CRC register value is the value since all the byte has been performed .
0xFFFF CRC register at first, deals with
register by transferring one process
exclusive with
of the message
、
1.One 16-bit register value is set to FFFF (hex), named CRC register.
2.The first 8-bit character of data is exclusive with the low 8 bits of the 16 bits CRC register, and the result is saved to
CRC register.
3.CRC register moves one bit toward right (LSB) MSB is fulled with zero, move check it.， LSB out and
4.When LSB is 0 repeat the third step：；
5.Repeat the third step and the fourth step until the 8th shift finished. At this time, one 8-bit data is finished.
6.Repeat the second and the fifth step until all data is finished.
7.The final CRC data is CRC value .
CRC simple function is shown as following：
{
unsigned int crc_value=0xFFFF;
int i;
while(length- -)
{
{
crc_value^=*data_value++;
for(i=0;i<8;i++);
if(crc_value&0x0001)
unsigned int crc_dhk_yalue(unsigned char*data_value,unsignde char length)
Note: When CRC added to the message, low byte prior to high byte.
When LSB is 1 CRC register and preset value A001H 1010 0000 0000 0001B perform exclusive operation .：：（）
The follows：process of CRC calculation is as
Check Mode ——CRC check mode：CRC（Cyclical Redundancy Check)：
crc_value=(crc_value>>1)^0xa001;
crc_value=crc_value>>1;
return(crc_value);
else
{
}
}
}
{
}
}
Chapter 7 EH600 Communication Protocol and Description of Communication

Xilinx EH600 A Series Specifications

General

Brand	Xilinx
Model	EH600 A Series
Category	Inverter
Language	English