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RACELOGIC Support Centre

VBOX Sport Serial (RS232) Protocol

Default message format

$VBSPT$,nnnniiii,stttaaaaoooovvhheeezzxxyybbmmmmffffddcc

The $VBSPT$ and commas are in ASCII, the rest is in binary

The four bytes of the nnnn field indicate the presence of standard channels in the data stream.

The four bytes of the iiii field indicate the presence of extended channels in the data stream.

Standard channels examples

  1. If only ‘sats’ and ‘speed’ are present the corresponding bit masks 0x00000001 and 0x00000010 would equate to the nnnn field equaling 0x00000011.
  2. If ‘sats’, ‘time’, ‘latitude’, ‘longitude’, ‘speed’, ‘heading’, ‘height’, ‘vertical velocity’, ‘lat.acc.’ and ‘long.acc.’ are present then the nnnn field would equal 0x000003FF.

Extended channels examples

  1. If only ‘battery time to empty’ is present the iiii field would equal 0x00000001.
  2. If ‘battery time to empty’, ‘media capacity’, ‘media free space’ and ‘HDOP’ are all present, the iiii field would equal 0x00000071.

Note: Some bit flags are not used, while others are not available in production units.

Default channels

Bluetooth

At the time of writing the default channels are:

  • Standard channels 0x000003FF
    Satellites, time, latitude, longitude, speed, heading, height, vertical speed, longitudinal acceleration and lateral acceleration.
     
  • Extended channels 0x00000071
    Battery time to empty, media capacity, media free space, HDOP.

USB

At the time of writing the default channels are:

  • Standard channels 0x000000FF
    Satellites, time, latitude, longitude, speed, heading, height, vertical speed.
     
  • Extended channels 0x00000000
    None.

Fields List

Note that for clarity, the fields are colour coded: 

  • The meta-data fields are Green.
  • The standard channel fields are Blue.
  • The extended channel fields are Purple.
  • Any unsupported channels are uncoloured.

 

Code in default message format Bytes Description Bit mask
$VBSPT$ 7 Header
$VBSPT$
 
, 1 Comma  
nnnn 4 Standard Channel Flags
0x000003FF
 
iiii 4 Extended Channel Flags
0x00000071
 
, 1 Comma  
s 1

Satellites

Bits 0-6 are number of satellites used

Bit 7 is set if the VBOX SPORT is using DGPS

0x00000001
ttt 3 Time
Number of 10 ms ticks since midnight UTC
0x00000002
aaaa 4

Latitude

(minutes * 100,000)

Positive = North, Negative = South

0x00000004
oooo 4

Longitude

(minutes * 100,000)

Positive = West, Negative = East

0x00000008
vv 2 Speed
Velocity in knots * 100
0x00000010
hh 2 Heading
Degrees from true north * 100
0x00000020
eee 3

Height

Altitude in metres WGS84 * 100

True signed 24 bit number

0x00000040
zz 2 Vertical Speed
Vertical speed in m/s
0x00000080
xx 2 Long acc (GPS)
Longitudinal acceleration in g * 100
0x00000100
yy 2 Lat acc (GPS)
Lateral acceleration in g * 100
0x00000200
  4 Brake distance 0x00000400
  4 Distance
In m * 128000
0x00000800
  4 Internal analogue 1 0x00001000
  4 Internal analogue 2 0x00002000
  4 Internal analogue 3 0x00004000
  4 Internal analogue 4 0x00008000
  1 Glonass sats 0x00010000
  1 GPS sats 0x00020000
  2 Yaw 0 value 0x00040000
  2 Yaw 0 LatAcc 0x00080000
  2 Yaw 0 Status 0x00100000
  2 Yaw 1 value 0x00200000
  2 Yaw 1 LatAcc 0x00400000
  2 Yaw 1 Status 0x00800000
  4 Velocity quality 0x01000000
  4 Temperature
In degrees C * 100
0x02000000
  2 Buffer size 0x04000000
  3 Media Free Space
(0xEF7FF – ((percent_free / 100) * 0xEF7FF))
0x08000000
  4 Event time 1 0x10000000
  2 Event time 2 0x20000000
  2 Internal voltage 0x40000000
  2 Battery voltage
In mV
0x80000000
bb 2 Battery time to empty
In minutes. TTE field from gas gauge. A value of 0xFFFF is shown if the battery is not discharging.
0x00000001
  2 Battery time to full
In minutes. TTF field from gas gauge. A value of 0xFFFF is shown if the battery is not charging
0x00000002
  2 Battery charge when full
In mAh. FCC field from gas gauge
0x00000004
  2 Battery current charge
As a percentage of charge when full. RM field from gas gauge
0x00000008
mmmm 4 Media capacity
In kb
0x00000010
ffff 4 Media free space
In kb
0x00000020
dd 2 HDOP
Value * 100
0x00000040
cc 2 Checksum
CRC of message, See Note 1*
 

 

*Note 1

CRC Calculation example:

s[n] is a string containing the message

Polynomial:= 4129 (0x1021)

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;

Troubleshooting

"I am only receiving a message containing '$VBSPT' from the VBOX Sport"

Please interpret the data as binary to resolve this issue. “$VBSPT” is a header and is in ASCII whilst the rest of the data is binary. Please see the section entitled: ‘Default message format’ at the top of this document for further information.

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