Comet Synertia RF - Calculation of the CRC16 Checksum; Table 38: Structure of a Response to a Write Command Via RS-232; Table 39: Structure of a Response to an Invalid Request Via RS-232

User Manual Synertia® RF Generator 99
The information contained in this manual is subject to change by Comet Yxlon without prior notice.
Header
Command Number
Data
CRC16
Byte
Number
1
2
3
4
5
…
n
(
≤ 253)
n + 1
n + 2
(
≤ 255)
Name
Address
Function
Code
Command
Number
Between 1 and 249 bytes of
data
CRC16 checksum
Description
0x0A
(fixed)
0x41 or
0x42
High
Byte
Low
Byte
D1
…
Dx (max.
249)
Calculated over
bytes number 1 to n
Table 38: Structure of a response to a write command via RS-232
Header
CRC16
Byte
Number
1
2
3
4
5
Name
Address
Exception
Function Code
Exception
Code
CRC16 checksum
Description
0x0A (fixed)
Received function
code with the
highest bit set to 1
Exception code
number
Calculated over bytes
number 1 to 3
Table 39: Structure of a response to an invalid request via RS-232
10.2.3 Calculation of the CRC16 checksum
The CRC16 checksum – Cyclic Redundancy Check – consists of two bytes and is based on
the CRC-16-ANSI standard with reversed representation (0xA001) of the polynomial.
For more details, see:
https://en.wikipedia.org/wiki/Cyclic_redundancy_check
.
The checksum is calculated over the whole message packet (request or response),
excluding the CRC16 itself.