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RACELOGIC Support Centre

VBOX Video HD2 Serial (RS232) Protocol

VBOX Video HD2 Serial String Format

115200 Baud, no parity, 8 data bits, 1 stop bit

Message format: 

$VBOXV$,nnnnffff,stttaaaaoooovvhheeezzxxyymmmcc

The $VBOXV$ and commas are in ASCII, the rest are in binary
 

  Format Bytes Description nnnn, bit mask.
nnnn   4 Reserved to indicate channel presence (always 0x080003FF on VBOX Video HD2)  
ffff   4

Status Flags

Bit      Description

4         Logging active

6         Media full

7         Media available

 
s Integer 1

Satellites
Number of satellites

0x00000001
ttt Integer 3

Time
Number of 10 ms ticks since midnight UTC

0x00000002
aaaa Signed 4

Latitude

(MMMM.MMMMM * 100,000)

Signed Integer of Decimal minutes *100,000.

Positive = North, Negative = South

0x00000004
oooo Signed 4

Longitude

(MMMMM.MMMMM * 100,000)

Signed Integer of Decimal minutes *100,000.

Positive = West, Negative = East

0x00000008
vv Integer 2

Velocity
Velocity in knots * 100

0x00000010
hh Integer 2

Heading
Degrees from true north * 100

0x00000020
eee Integer 3

Height

Altitude in metres WGS84 * 100

True signed 24 bit number

0x00000040
zz Signed 2

Vertical Velocity
Vertical velocity in m/s * 100

0x00000080
xx Signed 2

Long acc (GPS)
Longitudinal acceleration in g * 100

0x00000100
yy Signed 2

Lat acc (GPS)
Lateral acceleration in g * 100

0x00000200
mmm Integer 3

RAM Address
Free space on SD *980991 = Full, 0 = Empty

0x08000000
cc   2 Checksum
CRC of message, See Note 1*
 

 

*Note 1

CRC Calculation example:

s[n] is a string containing the message

Polynomial:= 4129

CRC:=0;

for Loop:=1 to Length(s) do

begin

Temp:=s[Loop];

CRC:= CRC xor (integer(Temp) * 256);

CRC:= CRC mod 65536;

for i:=7 downto 0 do

begin

if ( (CRC and 32768)=32768) then

begin

CRC:= CRC *2 ;

CRC:= CRC xor Polynomial;

end

else

begin

CRC:= CRC *2 ;

end;

CRC:=CRC mod 65536;

end;

end;

result:=CRC; 

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