The Data Field contains the data corresponding to the Command to be executed. The
data field cannot be empty.”
1.
An ACKnowledged message contains length, current command, Data and CRC.
2.
Non-ACKnowledged message contains length, current command, ”command
NACK/CRC mismatch /unknown command” and CRC.
Contents of the CRC-8 Field
The error checking field contains an 8 bit value which is the result of a Cyclic
Redundancy Check (CRC) calculation performed on the message contents.
The CRC field is appended to the message as the last field in the message.
Error handling case:
The failure case :
a mismatch is detected between the length byte and the actual
data sent or an unknown command or command not executed.
The reply will be a 4 bytes frame:
Length
Command
Command Error
0x00- No Error/No data
0xFF- NACK
0xCC - Crc mismatch
0xEE - Unknown command
CRC-8
Each command message frame must be transmitted in a continuous stream, i.e.
not byte by byte
It is advised to maintain a time interval of a few microseconds between two
messages for proper command registration
3.3.2. List of commands
Description
Query in HEX
Response in HEX
ENABLE LOW POWER
Sensor goes into low
power mode
0x03 0x07 0xA2 0xB1
0x03 0x07 0xXX CRC
Where XX can be an ACK or NACK
LOW POWER WAKEUP
Sensor wakes up from
0x03 0x08 0xA3 0x75
0x03 0x08 0xXX CRC
Where XX can be an ACK or NACK
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