Bluetooth 5.0 communication protocol
Bluetooth 5.0 communication protocol
Bluetooth 5.0 communication protocol
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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%
| Register value | Voltage value | Battery percentage |
|---|---|---|
>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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