SENA Rhio10 - Manual (Page 50)

50
- LRC (BCC)
Checks for any Errors in the command block.
Bytewise XORed value from START FLAG field to DATA field
(refer to example below)
- END FLAG
CR+LF ( 0x0D+0x0A )
-. The data of LENGTH and LRC is expressed as follows.
Each 4-bit nibble (upper 4-bit nibble and lower 4-bit nibble) is expressed as 1
Byte data. The 1-byte conversion of the 4-bit data is as follows.
0x0 ~ 0x9  0x30 ~ 0x39, 0xA ~ 0xF  0x41 ~ 0x46
If the Rhio receives the data converted, then it converts it to original by inverse.
-. The timeout from the start of the frame to the time when it receives LF is 5 sec.
-. Rhio will discard the command if there is any error in the command received (BCC
Error or Time Out) and will wait for the next command (Users have to write a code so that it will
have to wait at least 5 sec if there is no response from Rhio after sending the command.)
*
An Example of the LRC calculation is as follows :
XOR from Start Flag field to the Data Field use the following as an example :
(3A) (30 33) (30 33) (30) (30 41) (0D 0A)
Do the following :
((((3A xor 30) xor 33) xor 30) xor 33) xor 30 = 0A
0A gets translated as 0 and A, the byte conversion, which is as follows:
0x0 ~ 0x9 gets converted as 0 and A, the byte conversion, which is as follows :
0x0 ~ 0x9 gets converted to 0x30 ~ 0x39
0xA ~ 0xF gets converted to 0x41 ~ 0x46
In the case of above 0 =30 and A = 41, thus the LRC is 30 41, as shown above.
5.3.1.2 NAK Response
- NAK Response condition
-. When there is Data BCC Error when receiving the command
-. When the command data is not completed within 1 sec after it is started (Time out)
-. When the length of the Data frame is not same as the one in the command
(Frame Length error)