Support UP-Flow LC302 Optical Flow Module

[digitalentity]

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[Sebbb]

Here is the manual with the protocol for this LC302 module (unfortuantely in chinese, but I was able to read it with Google Translate)

https://github.com/Sebbb/inav/raw/lc302/docs/hardware/LC-302-3C_V1.1.pdf

The data structure of the external output of the optical flow module is defined as follows:

typedef struct   optical_flow_data
{
int16_t flow_x_integral; // The cumulative   displacement of X pixels in the cumulative time (radians*10000)
                                     // [Divide by   10000 and multiply by height (mm) and then the actual displacement (mm)]
int16_t flow_y_integral; // The cumulative   displacement of Y pixel points in the cumulative time (radians*10000)
                                      // [Divide by   10000 and multiply by height (mm) and then the actual displacement (mm)]
uint16_t   integration_timespan; // The cumulative time from the last optical flow data   transmission to the current optical flow data transmission (us)
uint16_t   ground_distance; // Reserved. The default is 999 (0x03E7)
uint8_t valid; // Status value: 0   (0x00) means optical flow data is not available
                     //245(0xF5) is   available for optical flow data
uint8_t version; //version number

1	0xFE	The start identifier of the packet (fixed value 0xFE)
2	0x0A	Number of bytes of optical flow data structure (fixed value 0x0A)
3	low byte of flow_x_integral	The cumulative displacement of X pixel points in the cumulative time,
		(radians*10000)
		[Divide by 10000 and multiply by the height (mm) to obtain the actual displacement (mm)]
4	high byte of flow_x_integral
5	low byte of flow_y_integral	The cumulative displacement of Y pixel points in the cumulative time,
		(radians*10000)
		[Divide by 10000 and multiply by the height (mm) to obtain the actual displacement (mm)]
6	high byte of flow_y_integral
7	low byte of integration_timespan	The optical flow data sent last time to the optical flow data sent this time
		Cumulative time (us)
8	high byte of integration_timespan
9	low byte of ground_distance	Reserved. The default is 999 (0x03E7)
10	high byte of ground_distance
11	valid	Status value: 0 (0x00) means optical flow data is not available,
		245 (0xF5) is available for optical flow data
12	version	Version number of the optical flow module
13	Check value Xor	Optical flow data structure (Byte 3~Byte 12) 10 bytes
		XOR
14	Packet tail 0x55	The end identifier of the data packet (fixed value 0x55)

[Sebbb]

I have this module, so if you need somebody to test, I can do that.