Datasheet
FS3000 Datasheet
Β© 2020 Integrated Device Technology, Inc.
12
September 9, 2020
8. Calculating Checksum
The checksum used for data integrity is the 2βs complement (negative) of the 256-modulo (8-bit) sum of the data bytes (does not include I2C
address).
Figure 7 shows the 5 bytes read:
Example:
Byte 1, 0xCC (Checksum)
Byte 2, 0x01
Byte 3, 0x99
Byte 4, 0x01 or 0x00
Byte 5, 0x99 or 0x00
The 256-modulo (8-bit) sum is calculated as:
π π’π = 0π₯01 + 0π₯99 + 0π₯01 + 0π₯99 = 0π₯134
Validating the data payload is done by calculating the sum and adding it to the checksum. If the result is 0x00, then the data is valid.
πβππππ π’π + π π’π = 0π₯πΆπΆ + 0π₯134 = 0π₯00