Bluetooth 5.0 communication protocol
Bluetooth 5.0 communication protocol
Bluetooth 5.0 communication protocol
Contact
Module to PC 1
acceleration angular velocity angle data packet (default) 2
Acceleration calculation method: unit g 3
Calculation method of angular velocity: unit °/s 3
Angle Calculation Method: Unit ° 3
A packet with a single return register 5
Magnetic field output 5
Quaternion output 6
temperature output 6
Host computer to module 7
Send command: 7
read register value 7
Acceleration Calibration and Magnetic Field Calibration 7
save configuration 7
set return rate 8
Read power 8
Register Address Table 9
Module to PC
The module uploads the data of Flag=0x61 (acceleration angular velocity angle) by default.
Flag=0x71 (magnetic field) needs to send the command to read the corresponding register to return.
Bluetooth upload data format: Bluetooth can upload data up to 20Byte each time.
acceleration angular velocity angle data packet (default)
packet header
1Byte
flag bit
1Byte
axL
axH
......
YawL
YawH
0x55
Flag
0xNN
0xNN
......
0xNN
0xNN
Note: 0xNN is the specific value received, the order of data return is acceleration X Y Z, angular velocity X Y Z, angle XYZ,
The low byte comes first, and the high byte follows.
Flag = 0x61 Data content 18Byte is acceleration, angular velocity, angle
0x55
packet header
0x61
flag bit
axL
X-axis acceleration low 8 bits
axH
X-axis acceleration high 8 bits
ayL
Y-axis acceleration low 8 bits
ayH
Y-axis acceleration high 8 bits
azL
Z-axis acceleration low 8 bits
azH
Z-axis acceleration high 8 bits
wxL
X-axis angular velocity low 8 bits
wxH
X-axis angular velocity high 8 bits
wyL
Y-axis angular velocity low 8 bits
wyH
Y-axis angular velocity high 8 bits
wzL
Z-axis angular velocity low 8 bits
wzH
Z-axis angular velocity high 8 bits
RollL
X-axis angle velocity low 8 bits
RollH
X-axis angle velocity high 8 bits
PitchL
Y-axis angle velocity low 8 bits
PitchH
Y-axis angle velocity high 8 bits
YawL
Z-axis angle velocity low 8 bits
YawH
Z-axis angle velocity high 8 bits
Acceleration calculation method: unit g
ax=((axH<<8)|axL)/32768*16g(g is the acceleration of gravity, it is desirable 9.8m/s2)
ay=((ayH<<8)|ayL)/32768*16g(g is the acceleration of gravity, it is desirable 9.8m/s2)
az=((azH<<8)|azL)/32768*16g(g is the acceleration of gravity, it is desirable 9.8m/s2)
Calculation method of angular velocity: unit °/s
wx=((wxH<<8)|wxL)/32768*2000(°/s)
wy=((wyH<<8)|wyL)/32768*2000(°/s)
wz=((wzH<<8)|wzL)/32768*2000(°/s)
Angle Calculation Method: Unit °
roll angle (x-axis)Roll=((RollH<<8)|RollL)/32768*180(°)
pitch angle (y-axis) Pitch=((PitchH<<8)|PitchL)/32768*180(°)
Yaw angle (z axis) Yaw=((YawH<<8)|YawL)/32768*180(°)
Note:
1. The coordinate system used in the settlement of the attitude angle is the northeast sky coordinate system, and the module is placed in the positive direction, such as "4 pin description"
Left is shown for the X axis, forward for the Y axis, and up for the Z axis. The rotation order of the coordinate system when the Euler angle represents the attitude
It is defined as Z-Y-X, that is, first rotate around the Z axis, then around the Y axis, and then around the X axis.
2. Although the range of the roll angle is ±180 degrees, in fact, because the coordinate rotation sequence is Z-Y-X, it represents the attitude
When , the range of the pitch angle (Y axis) is only ±90 degrees, and after exceeding 90 degrees, it will be changed to less than 90 degrees, and at the same time
Let the angle of the X axis be greater than 180 degrees. For the detailed principle, please Baidu the relevant information about Euler angle and attitude representation.
3. Since the three axes are coupled, they will show independent changes only at small angles, and the posture at large angles
The angle will be coupled and changed, for example, when the Y axis is close to 90 degrees, even if the attitude only rotates around the Y axis, the angle of the X axis
It will also change greatly, which is the inherent characteristic of Euler angles to express attitude.
illustrate:
1. Data is sent in hexadecimal, not ASCII.
2. Each data is transmitted sequentially in low byte and high byte, and the two are combined into a signed short type data.
For example, X-axis acceleration data Ax, where AxL is the low byte, and AxH is the high byte. The conversion method is as follows:
Assuming that Data is the actual data, DataH is its high byte, and DataL is its low byte, then: Data=((short)DataH<<8)|DataL. It must be noted here that DataH needs to be cast to a signed short first
The data of type will be shifted later, and the data type of Data is also a signed short type, so that negative numbers can be represented.
A packet with a single return register
A single return data packet needs to send a read register instruction first, and the instruction format is as follows:
--XX refers to the corresponding register number, the number of the register is for reference, and the example of sending the command is as follows：
function
command
read magnetic field
FF AA 27 3A 00
read four elements
FF AA 27 51 00
read temperature
FF AA 27 40 00
read power
FF AA 27 64 00
After sending this command, the module will return a data packet beginning with 0x55 0x71, which contains the corresponding start register address data, the start of the start register address and the following 7 register data (8 registers are fixedly uploaded), and the returned data format is as follows:
Start register (2Byte) + register data (16Byte, 8 registers)
packet header
sign
Start register address low
Start register address high
Start (1st) register data low bit
Open (1st) register number high bit
......
The low bit of the 8th register data
The 8th register data high bit
0x55
0x71
RegL
RegH
0xNN
0xNN
......
0xNN
0xNN
Note: 0xNN is the specific value received, the low byte comes first, and the high byte follows.
Magnetic field output
0x55
0x71
0x3A
0x00
HxL
HxH
HyL
HyH
HzL
HzH.....
Calculation method: unit mG
Magnetic field (x-axis) Hx=(( HxH<<8)| HxL)
Magnetic field (y axis) Hy=(( HyH <<8)| HyL)
Magnetic field (z axis) Hz =(( HzH<<8)| HzL)
Example: Send the command to read the magnetic field on the APP: FF AA 27 3A 00 (refer to 7.2.8 Read Register Value)
The module returns data to APP: 55 71 3A 00 68 01 69 00 7A 00 00 00 00 00 00 00 00 00 00 00, a total of 20 bytes.
For the 5th to 10th bytes, calculate as above, the magnetic field x=360, y=105, z=122.
Quaternion output
0x55
0x71
0x51
0x00
QxL
QxH
QyL
QyH
QzL
QzH.....
Calculation method:
Q0=((Q0H<<8)|Q0L)/32768
Q1=((Q1H<<8)|Q1L)/32768
Q2=((Q2H<<8)|Q2L)/32768
Q3=((Q3H<<8)|Q3L)/32768
checksum:
Sum=0x55+0x59+Q0L+Q0H+Q1L +Q1H +Q2L+Q2H+Q3L+Q3H
temperature output
0x55
0x71
0x40
0x00
TL
TH
......
Temperature calculation formula:
T=((TH<<8)|TL) /100 ℃
Host computer to module Send command:
read register value
FF AA 27 XX 00
read register value
--XX refers to the corresponding register.
example:
Read magnetic field: FF AA 27 3A 00
Read four elements: FF AA 27 51 00
Read temperature: FF AA 27 40 00
After sending this command, the module will return a data packet beginning with 0x55 0x71, which contains the corresponding start register address data, the beginning of the start register address and the following 7 register data (8 registers are fixedly uploaded), and the return data format refers to
Acceleration Calibration and Magnetic Field Calibration
FF AA 01 01 00
Acceleration Calibration
FF AA 01 05 00
Acceleration Calibration L
FF AA 01 06 00
Acceleration Calibration R
FF AA 01 07 00
Magnetic Field Calibration
FF AA 01 00 00
Complete Magnetic Field Calibration
save configuration
FF AA 00 SAVE 00
save configuration
SAVE: set
0: save the current configuration
1: Restore the default configuration and save
set return rate
FF AA 03 RATE 00
set return rate
RATE：return rate
0x01：0.1Hz
0x02：0.5Hz
0x03：1Hz
0x04：2Hz
0x05：5Hz
0x06：10Hz（default）
0x07：20Hz
0x08：50Hz
0x09：100Hz
0x0A：200Hz
Read power
FF AA 27 64 00
Read the power of the module
return data：55 71 64 00 48 03 00 00 AA 00 00 00 00 00 00 00 00 00 00 00
Among them, the two data of 48 03 represent the power, which is 0348 when converted into a hexadecimal number, and 840 when converted into a decimal number, which means that the corresponding power is 100%.
The power relationship corresponding to the decimal number is as follows:
Greater than 830 is 100%
>396
> 3.96V
100%
393-396
3.93V-3.96V
90%
387-393
3.87V-3.93V
75%
382-387
3.82V-3.87V
60%
379-382
3.79V-3.82V
50%
377-379
3.77V-3.79V
40%
373-377
3.73V-3.77V
30%
370-373
3.70V-3.73V
20%
368-370
3.68V-3.70V
15%
350-368
3.50V-3.68V
10%
340-350
3.40V-3.50V
5%
<340
<3.40V
0%
Register Address Table
address
symbol
meaning
0x00
SAVE
save current configuration
0x01
CALSW
calibration
0x02
SAVE
0x03
RATE
return data rate
0x04
BAUD
Serial baud rate
0x05
AXOFFSET
X-axis acceleration zero bias
0x06
AYOFFSET
Y-axis acceleration zero bias
0x07
AZOFFSET
Z-axis acceleration zero bias
0x08
GXOFFSET
X-axis angular velocity zero bias
0x09
GYOFFSET
Y-axis angular velocity zero bias
0x0a
GZOFFSET
Z axis angular velocity zero bias
0x0b
HXOFFSET
X-axis magnetic field zero bias
0x0c
HYOFFSET
Y-axis magnetic field zero bias
0x0d
HZOFFSET
Z-axis magnetic field zero bias
0x0e
D0MODE
D0 model
0x0f
D1MODE
D1 model
0x10
D2MODE
D2 model
0x11
D3MODE
D3 model
0x12
SAVE
0x13
SAVE
0x14
SAVE
0x15
SAVE
0x16
SAVE
0x17
SAVE
0x18
SAVE
0x19
SAVE
0x1a
SAVE
0x1b
SAVE
......
......
......
0x30
YYMM
Year,month
0x31
DDHH
day, time
0x32
MMSS
minutes, seconds
0x33
MS
millisecond
0x34
AX
X-axis acceleration
0x35
AY
Y-axis acceleration
0x36
AZ
Z-axis acceleration
0x37
GX
X-axis angular velocity
0x38
GY
Y-axis angular velocity
0x39
GZ
Z-axis angular velocity
0x3a
HX
X-axis magnetic field
0x3b
HY
Y-axis magnetic field
0x3c
HZ
Z-axis magnetic field
0x3d
Roll
X-axis angle
0x3e
Pitch
Y-axis angle
0x3f
Yaw
Z-axis angle
0x40
TEMP
module temperature
0x49
SAVE
0x4a
SAVE
0x4b
SAVE
0x4c
SAVE
0x4d
SAVE
0x4e
SAVE
0x4f
SAVE
0x50
SAVE
0x51
Q0
Four elements Q0
0x52
Q1
Four elements Q1
0x53
Q2
Four elements Q2
0x54
Q3
Four elements Q3
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