Instruction Manual

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CHART 2 SCAN COMMAND RESPONSE CONTENT DATA STRUCTURE
DESCRIPTION
Content
Name
Description
PH(2B)
Packet header
2B in length, fixed at 0x55AA, low in front, high in back
CT(1B)
Package type
Indicates the type of the current packet, CT[bit(0)]=1 means the beginning of a
lap of data, CT[bit(0)]=0 means point cloud data packet, CT[bit(7:1)] is reserve
bit
LSN(1B)
Sample quantity
Indicates the number of sampling points contained in the current packet. There
is only one initial point of data in the zero packet. The value is 1
FSA(2B)
Start angle
The angle data corresponding to the first sample point in the sampled data
LSA(2B)
End angle
The angle data corresponding to the last sample point in the sampled data
CS(2B)
Check code
The check code of the current data packet uses a two-byte exclusive OR to
check the current data packet
Si(2B)
Sample data
The sampling data of the system test is the distance data of the sampling point,
and the interference flag is also integrated in the LSB of the Si node
➢ Start bit and scan frequency analysis:
When CT[bit(0)] = 0 is detected, it indicates that the packet data is a point cloud data packet;
When CT[bit(0)] = 1 is detected, it indicates that the packet data is start packet. In this packet,
LSN=1, that is, the number of Si is 1; for the specific value analysis of the distance and angle, please
refer to the following; at the same time, in the start data packet, CT[bit(7:1)] scan frequency
information, F = CT[bit(7:1)]/10 (when CT[bit(7:1)] = 1).
Note: When CT[bit0]=0, CT[bit(7:1)] is a reserved bit, and future versions will be used for other purposes.
Therefore, in the process of parsing CT, only bit(0) is required to determine the starting frame.
➢ Distance analysis:
Distance solution formula: 

 



Among them,  is sample data. Set the sampling data as E5 6F. Since the system is in little-
endian mode, the sampling point S = 0x6FE5 is substituted into the Distance solution formula to
obtain the Distance=7161.25mm.
➢ Angle analysis:
Angle data is stored in FSA and LSA, and each Angle data has the following data structure,
where C is the check bit and the value is fixed to 1. There are two levels of angle analysis: first-level
analysis and second-level analysis. The first-level analysis obtains the initial value of the angle, and
the second-level analysis corrects the initial value of the angle. The specific process is as follows:
First-level analysis: