Toshiba BC Series Instruction Manual page 27

- How to calculate GenCP checksum
The specified field is cut out in 2 byte units, and the one's complement sum is taken to be one's complement.
The specification fields are as follows.
0x00
0x04
SCD checksu m (0xECCA)
0x08
0x0C
0x10
0x14
0x18
*CCD checksum
*SCD checksum
*The one's complement sum is taken to be one's complement.
- CCD checksum in the example
One's complement sum
=0x0000+0x4000+0x0802+0x000C+0x89AB
=0xD1B9
One's complement
=0xFFFF-0xD1B9
=0x2E46
- SCD checksum in the example
One's complement sum
=(CCD checksum complement)+0x0000+0x0000+0x0020+0x405C+0x0000+0x00FF
=0xD1B9+0x0000+0x0000+0x0020+0x405C+0x0000+0x00FF
=0x11334
=0x001+0x1334
=0x1335
One's complement
=0xFFFF-0x1335
=0xECCA
Copyright © 2019 Toshiba Teli Corporation, All Rights Reserved.
+0x0 +0x1
preamble (0x0100) CCD checksum (0x2E46)
flags (0x4000)
length (0x000C)
register address hi (0x00000000)
register address lo (0x0020405C)
data (0x000000FF)
：channel_id, CCD (In the example, the area of 0x06 to 0x0F)
：channel_id, CCD, SCD (In the example, the area of 0x06 to 0x1B)
：It has the same calculation method as the UPD Checksum of RFC768.
Please refer to the following about UPD of RFC768.
https://www.ietf.org/rfc/rfc768.txt
+0x2 +0x3
channel_id (0x0000)
command_id (0x0802)
request_id (0x89AB)
25 / 73
Prefix
CCD
(Common Command Data)
SCD
(Specific Command Data)
http://www.toshiba-teli.co.jp/en/
D4296087A