MagWrist_Hardware

About MagWrist

This is a project created by QINGHAO LIU. The basic idea is that:

The program of the system has two parts: Hardware(Embedded Board) and Software(PC).

This README Only talks about HARDWARE part.

Overview

We use an embedded board to read data from magnetometer and motion-sensor chip by I2C protocol.

If you are not familiar with I2C, we strongly recommend you to learn about it.

Embedded board:TI Cortex-M4 TM4C1294XL LaunchPad

Magnetometer: HMC5983

Motion sensor: MPU9250

10 I2C masters are used to drive 10 magnetometers and load data from magnetometers in sequence.

One of the 10 I2C masters is also used to drive the motion sensor, since the device addresses of motion-sensor and magenetometer are different, so there is no conflict.

Then the data loaded from sensors will be transferred to Serial Port by UART in format.

About TI Cortex-M4 Embedded Board

You can refer to Cortex-M4 TM4C1294XL LaunchPad User Guide

Map of I2C Master to pins on the embedded board

The pins on the front side is enough(Boosterpack 1 and 2 written in white).

xxxx	Debug port	xxxx	xxxx	xxxx
3.3V	5V		PF1	GND
PE4	GND		PF2	PM3
PC4	PE0		PF3	PH2
PC5	PE1		PG0(I2C1 SCL)	PH3
PC6	PE2		PL4	~RST
PE5	PE3		PL5	PD1(I2C7' SDA)
PD3(I2C8' SDA)	PD7		PL0(I2C2' SDA)	PD0(I2C7' SCL)
PC7	PA6(I2C6 SCL)		PL1(I2C2' SCL)	PN2
PB2(I2C0 SCL)	PM4		PL2	PN3
PB3(I2C0 SDA)	PM5		PL3	PP2
~	~	~	~	~
3.3V	5V		PG1(I2C1 SDA)	GND
PD2(I2C8' SCL)	GND		PK4(I2C3 SCL)	PM7
PP0	PB4(I2C5 SCL)		PK5(I2C3 SDA)	PP5
PP1	PB5(I2C5 SDA)		PM0	PA7(I2C6 SDA)
JP4(PD4/PA0(I2C9 SCL))	PK0		PM1	~RESET
JP5(PD5/PA1(I2C9 SDA))	PK1		PM2	PQ2/PA3(I2C8 SCL)
PQ0	PK2		PH0	PQ3/PA2(I2C8 SDA)
PP4	PK3		PH1	PP3
PN5(I2C2 SCL)	PA4(I2C7 SCL)		PK6(I2C4 SCL)	PQ1
PN4(I2C2 SDA)	PA5(I2C7 SDA)		PK7(I2C4 SDA)	PM6

About magnetometer HMC5983

HMC5983 is a 3-Axis magnetometer chip made by Honeywell, which is very cheap and sensitive to magnetic field.

To get started with it. The pin-map and scheme-map below may help you.

For more details, you can refer to the data sheet of HMC5983 here

About motion sensor MPU9250

MPU9250 is a 6-Axis motion sensor chip made by InvenSense, which also include a magentometer.

To get started with it, the Scheme-map below may help you.

For more details, you can refer to the product specification and Register map

Magnetometer Array

Map of sensors on the Magnetometer Array

Map of Pins of magnetometer array

Pins of magnetometer from up to down.

1. GND
2. Sensor-0 SDA
3. Sensor-0 SCL
4. GND
5. Sensor-1 SDA
6. Sensor-1 SCL
7. GND
8. Sensor-2 SDA
9. Sensor-2 SCL
10. GND
11. Sensor-3 SDA
12. Sensor-3 SCL
13. GND
14. Sensor-4 SDA
15. Sensor-4 SCL
16. GND
17. VDDIO of Motion Sensor(Please connect it to 3.3V)
18. Motion Sensor SCL
19. Motion Sensor SDA
20. GND
21. Sensor-5 SDA
22. Sensor-5 SCL
23. GND
24. Sensor-6 SDA
25. Sensor-6 SCL
26. GND
27. Sensor-7 SDA
28. Sensor-7 SCL
29. GND
30. Sensor-8 SDA
31. Sensor-8 SCL
32. GND
33. Sensor-9 SDA
34. Sensor-9 SCL
35. GND
36. N/A
37. N/A
38. N/A
39. 5V
40. 5V

System Architecture

Connect 10 I2C masters to 10 magnetometers. Connect one of the 10 I2C masters to 1 motion-sensor.

Install Keil(TI Cortex-M4 Development Environment)

Due to the problem of copyright. Ask your professor for the installation program, which may contains 5 files.

Installation program name	Details
MDK522.EXE	The main setup file of Keil 5.22
MDKCM522.EXE	The setup file for Keil legacy devices
Keil.TM4C_DFP.1.1.0.pack	Tiva C Series device support and examples
SW-EK-TM4C1294XL-2.1.4.178.exe	Firmware development package setup
uniflash_sl.4.1.1250.exe	Uniflash setup(Maybe no use)

Test the hardware program

1. Download this repository to your PC.
2. Find the MagWrist_ReadData.uvprojx file and open it with Keil. (picture here about the postion of the src file)
3. Double click the MagWrist_ReadData.c file on the left side.
4. Configuration.
   1. (Read Data Rate)
   2. (Measurement Scale)
5. Click on the Rebuild button on the up-left side.
   1. If 0 Error(s), then Congratulations!(Ignore the warnings)
   2. If there is any error, try debug it by yourself first.
      1. Check whether there is any syntax error.(Maybe you tapped your keyboard by mistake)
      2. Right click Target1 on the left side and choose Options for Target 'Target 1'.
      3. Click Device and check you have chosen TM4C1294NCPDT.
      4. Click C/C++ and check Include Paths is .\inc;.\driverlib_.
   3. If you have no idea, ask your professor.
6. Connect embedded board by USB and download the program into your embedded board.
7. If you have some problem with downloading, please right click on the Target1 on the left side and click Options for Target 'Target 1' .... Choose Debug and follow the pictures below and try again:

8. If you still have some problems, please ask your professor. :)

Output format

The data loaded will be translated into ASCII and transferred to Serial Port by UART.

The format is as follows:

/* HMC5983 Part */
X_Axis_Data Y_Axis_Data Z_Axis_Data 0
X_Axis_Data Y_Axis_Data Z_Axis_Data 1
X_Axis_Data Y_Axis_Data Z_Axis_Data 2
X_Axis_Data Y_Axis_Data Z_Axis_Data 3
...
X_Axis_Data Y_Axis_Data Z_Axis_Data 9
/* MPU9250 Part */
Acc_X Acc_Y Acc_Z Gyr_X Gyr_Y Gyr_Z  0

Now you can receive data on your PC if you know how to read data from serial port of your PC.

If you have no idea, please refer to Software part of this project.

Resolution Configuration

You can configure the resolution of the magnetometers(HMC5983). Higher the resolution you set, more sensitive the sensor is, smaller the range is. HMC5983 has 8 levels of resolution, which controlled by three higher bits of Configuration B Register. If you want to change the resolution, follow the steps below:

1. Open MagWrist_ReadData.c in Keil(or other editor).

2. Search for the function HMC5983_Config.

3. You can find this line:

I2C_WriteByte(I2C_Num,HMC5983_ADDRESS,HMC5983_CONFIG_B,0xE0);

4. You can replace the hex according to the table below:

Hex	Range	Digtal Resolution(mGauss/LSb)	Output Number Range
0x00	-0.88 ~ +0.88 Gauss	0.73	0xF800 ~ 0x07FF(-2048 ~ 2047)
0x20	-1.30 ~ +1.30 Gauss	0.92	0xF800 ~ 0x07FF(-2048 ~ 2047)
0x40	-1.90 ~ +1.90 Gauss	1.22	0xF800 ~ 0x07FF(-2048 ~ 2047)
0x60	-2.50 ~ +2.50 Gauss	1.52	0xF800 ~ 0x07FF(-2048 ~ 2047)
0x80	-4.00 ~ +4.00 Gauss	2.27	0xF800 ~ 0x07FF(-2048 ~ 2047)
0xA0	-4.70 ~ +4.70 Gauss	2.56	0xF800 ~ 0x07FF(-2048 ~ 2047)
0xC0	-5.60 ~ +5.60 Gauss	3.03	0xF800 ~ 0x07FF(-2048 ~ 2047)
0xE0	-8.10 ~ +8.10 Gauss	4.35	0xF800 ~ 0x07FF(-2048 ~ 2047)

5. Rebuild and download.

Notification

The head files and functions defined except MagWrist_ReadData.c are provided by Prof. Wei Liu Shanghai Jiaotong University.

The printed circuit board(Magnetometer Array) is designed and made by Prof. Hao He Shanghai Jiaotong University, supported by Prof. Hongzi Zhu Shanghai Jiaotong University.