ST NUCLEO-F401RE Nucleo Development Board User Manual

The MotionCP library expands the functionality of X-CUBE-MEMS1
software by acquiring accelerometer data and determining the user’s
device carrying position.

Implementation Requirements

The library is compatible with X-NUCLEO-IKS4A1 and
X-NUCLEO-IKS01A3 expansion boards mounted on NUCLEO-F401RE,
NUCLEO-U575ZI-Q, or NUCLEO-L152RE development boards.

Accessing Library Information

Technical details about MotionCP APIs can be found in the
MotionCP_Package.chm file located in the Documentation folder of
the software package.

MotionCP APIs

MotionCP_GetLibVersion(char *version): Retrieves
the library version
MotionCP_Initialize(void): Initializes the carry
position library and enables the required CRC module in the STM32
microcontroller

MotionCP_Update(MCP_input_t *data_in, MCP_output_t *data_out): Updates the library with accelerometer sensor
data and outputs the carrying position
MotionCP_SetOrientation_Acc(const char *acc_orientation): Sets the orientation of the accelerometer
data output

Frequently Asked Questions (FAQ)

Q: Can I use the MotionCP library with non-ST MEMS
sensors?

A: The library is specifically designed for ST MEMS sensors.
Using other sensors may result in different performance and
functionality.

Q: What is the required accelerometer data sampling frequency
for MotionCP library?

A: The library requires a sampling frequency of 50 Hz for
accurate detection of carrying positions.

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UM2224
User manual
Getting started with MotionCP real-time carry position library in X-CUBE-MEMS1 expansion for STM32Cube
Introduction
The MotionCP middleware library is part of the X-CUBE-MEMS1 software and runs on STM32. It provides real-time information about how the user is carrying a device (i.e. cell phone). It is able to distinguish the following positions: on desk, in hand, near head, shirt pocket, trouser pocket, swinging arm and jacket pocket. This library is intended to work with ST MEMS only. The algorithm is provided in static library format and is designed to be used on STM32 microcontrollers based on the ARM® Cortex®-M3, ARM® Cortex®-M33, ARM® Cortex®-M4 or ARM® Cortex®-M7 architecture. It is built on top of STM32Cube software technology to ease portability across different STM32 microcontrollers. The software comes with sample implementation running on X-NUCLEO-IKS4A1 or X-NUCLEO-IKS01A3 expansion board on a NUCLEO-F401RE, NUCLEO-U575ZI-Q or NUCLEO-L152RE development board.

UM2224 – Rev 6 – July 2025 For further information, contact your local STMicroelectronics sales office.

www.st.com

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Acronyms and abbreviations

Acronyms and abbreviations

Acronym API BSP GUI HAL IDE

Table 1. List of acronyms

Application programming interface Board support package Graphical user interface Hardware abstraction layer Integrated development environment

Description

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2
2.1 2.2
2.2.1
2.2.2 Note:

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MotionCP middleware library in X-CUBE-MEMS1 software expansion for STM32Cube

MotionCP middleware library in X-CUBE-MEMS1 software expansion for STM32Cube

MotionCP overview
The MotionCP library expands the functionality of the X-CUBE-MEMS1 software.
The library acquires data from the accelerometer and provides information about how the user is carrying the device.
The library is designed for ST MEMS only. Functionality and performance when using other MEMS sensors are not analyzed and can be significantly different from what described in the document.
A sample implementation is available for X-NUCLEO-IKS4A1 and X-NUCLEO-IKS01A3 expansion boards, mounted on a NUCLEO-F401RE, NUCLEO-U575ZI-Q or NUCLEO-L152RE development board.

MotionCP library
Technical information fully describing the functions and parameters of the MotionCP APIs can be found in the MotionCP_Package.chm compiled HTML file located in the Documentation folder.

MotionCP library description

The MotionCP carry position recognition library manages the data acquired from the accelerometer; it features:

possibility to distinguish the following positions: on desk, in hand, near head, shirt pocket, trouser pocket,

arm swing, jacket pocket

recognition based on the accelerometer data only

required accelerometer data sampling frequency of 50 Hz

resources requirements:

Cortex-M3: 6.8 kB of code and 11.0 kB of data memory

Cortex-M33: 6.9 kB of code and 11.0 kB of data memory

Cortex-M4: 6.8 kB of code and 11.0 kB of data memory

Cortex-M7:7.0 kB of code and 11.0 kB of data memory

available for ARM® Cortex®-M3, ARM® Cortex®-M33, ARM® Cortex®-M4 and ARM® Cortex®-M7

architectures

MotionCP APIs

The MotionPE library APIs are:

uint8_t MotionCP_GetLibVersion(char *version)

retrieves the library version

*version is a pointer to an array of 35 characters

returns the number of characters in the version string

void MotionCP_Initialize(void)

performs MotionCP library initialization and setup of the internal mechanism

This function must be called before using the carry position library and the CRC module in the STM32 microcontroller (in RCC peripheral clock enable register) has to be enabled.

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MotionCP middleware library in X-CUBE-MEMS1 software expansion for STM32Cube

void MotionCP_Update(MCP_input_t *data_in, MCP_output_t *data_out)

executes carry position algorithm

*data_in parameter is a pointer to a structure with input data

the parameters for the structure type MCP_input_t are:

AccX is the accelerometer sensor value in X axis in g

AccY is the accelerometer sensor value in Y axis in g

AccZ is the accelerometer sensor value in Z axis in g

*data_out parameter is a pointer to an enum with the following items:

MPE_UNKNOWN = 0

MCP_ONDESK = 1

MCP_INHAND = 2

MCP_NEARHEAD = 3

MCP_SHIRTPOCKET = 4

MCP_TROUSERPOCKET = 5

MCP_ARMSWING = 6

MCP_JACKETPOCKET = 7

void MotionCP_SetOrientation_Acc(const char *acc_orientation)

this function is used to set the accelerometer data orientation

configuration is usually performed immediately after the MotionCP_Initialize function call

*acc_orientation parameter is a pointer to a string of three characters indicating the direction of
each of the positive orientations of the reference frame used for accelerometer data output, in the sequence x, y, z. Valid values are: n (north) or s (south), w (west) or e (east), u (up) or d (down). As shown in the figure below, the X-NUCLEO-IKS4A1 accelerometer sensor has an SEU orientation (x – South, y – East, z – Up), so the string is: “seu”.

Figure 1. Example of sensor orientations

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2.2.3

API flow chart

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MotionCP middleware library in X-CUBE-MEMS1 software expansion for STM32Cube
Figure 2. MotionCP API logic sequence Start
Initialize GetLibVersion SetOrientation_Acc
Wait Expiring Timer Data Read Interrupt
Read Accelerometer Data Update
Get Carry Position Code

2.2.4

Demo code The following demonstration code reads data from the accelerometer sensor and gets the carry position code.
[…] #define VERSION_STR_LENG 35 […] /* Initialization */ char lib_version[VERSION_STR_LENG]; char acc_orientation[3];
/* Carry position API initialization function */ MotionCP_Initialize();
/* Optional: Get version */ MotionCP_GetLibVersion(lib_version);
/* Set accelerometer orientation */ acc_orientation[0] =’n’;

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2.2.5 Note:

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MotionCP middleware library in X-CUBE-MEMS1 software expansion for STM32Cube
acc_orientation[1] =’w’; acc_orientation[2] =’u’; MotionCP_SetOrientation_Acc(acc_orientation);
[…] /* Using Carry Position algorithm */ Timer_OR_DataRate_Interrupt_Handler() {
MCP_input_t data_in; MCP_output_t data_out;
/* Get acceleration X/Y/Z in g */ MEMS_Read_AccValue(&data_in.AccX, &data_in.AccY, &data_in.AccZ);
/* Carry Position algorithm update */ MotionCP_Update(&data_in, &data_out); }
Algorithm performance The carry position recognition algorithm only uses data from the accelerometer and runs at a low frequency (50 Hz) to reduce power consumption. The detected position is a phone typical carry position as the algorithm is sensitive to orientation, in particular for in hand and near head positions. Some other carry positions (like arm swing and trouser pocket) are only detected when the person is walking. When replicating phone activity with the STM 32 Nucleo board, ensure the USB connector is oriented downwards, as it is on a phone (see the figure below).
Figure 3. STM32 Nucleo vs phone orientation

Carry position

Detection
probability (typical)(1)

On desk

95.31%

In hand

99.31%

Near head

96.31%

Table 2. Algorithm performance data

Best performance

Susceptible

Normal use cases when phone is on desk

Vulnerable to sustained vibrations like banging on the desk or continuously tapping on the phone

Correct orientation; i.e., natural phone carrying positions Horizontal orientation/

in hand while looking, reading or texting. Robust for

panorama orientation are not

stationary, walking and fast walking scenarios.

considered

Correct orientation,i.e. carrying phone while talking. Robust for stationary, walking and fast walking scenarios.

Wrong orientation

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MotionCP middleware library in X-CUBE-MEMS1 software expansion for STM32Cube

Carry position

Detection
probability (typical)(1)

Best performance

Shirt pocket 98.29%

Robust for walking and fast walking scenarios.

Trouser pocket 98.68%

Robust for walking scenarios, for both front and back trouser pockets and multiple orientation in which the phone can be carried while it is in in the trouser pocket.

Swinging arm 97.68%

Walking

Jacket pocket 94.73%

Walking

1. Typical specifications are not guaranteed.

Susceptible
For stationary scenarios, the torso posture determines the algorithm performance
Stationary
Stationary Stationary

Typical detection latency is 5 second.

Table 3. Algorithm elapse time (µs) Cortex-M4, Cortex-M3

Cortex-M4 STM32F401RE at 84 MHz

Min

Avg

Max

141

190

2780

Cortex-M3 STM32L152RE at 32 MHz

Min

Avg

Max

502

680

9887

Table 4. Algorithm elapse time (µs) Cortex-M33 and Cortex-M7

Cortex- M33 STM32U575ZI-Q at 160 MHz

Min

Avg

Max

1484

Cortex- M7 STM32F767ZI at 96 MHz

Min

Avg

Max

267

391

6277

2.3

Sample application

The MotionCP middleware can be easily manipulated to build user applications.

A sample application is provided in the Application folder. It is designed to run on a NUCLEO-F401RE, NUCLEOU575ZI-Q or NUCLEO-L152RE development board connected to an X-NUCLEO-IKS4A1 or X-NUCLEO-IKS01A3 expansion board.

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MotionCP middleware library in X-CUBE-MEMS1 software expansion for STM32Cube
Figure 4. STM32 Nucleo: LEDs, button, jumper

The above figure shows the user button B1 and the three LEDs of the NUCLEO-F401RE board. Once the board is powered, LED LD3 (PWR) turns ON.
A USB cable connection is required to monitor real-time data. The board is powered by the PC via USB connection. This working mode allows the user to display real-time carry positions, accelerometer data, time stamp and eventually other sensor data, using the MEMS-Studio.

2.4

MEMS Studio application

The sample application uses the Windows MEMS-Studio utility, which can be downloaded from www.st.com.

Step 1. Ensure that the necessary drivers are installed and the STM32 Nucleo board with appropriate expansion board is connected to the PC.

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MotionCP middleware library in X-CUBE-MEMS1 software expansion for STM32Cube

Step 2.

Launch the MEMS-Studio application to open the main application window.
If an STM32 Nucleo board with supported firmware is connected to the PC, it is automatically detected. Press the [Connect] button to establish connection to the evaluation board.

Figure 5. MEMS-Studio – Connect

Step 3. When connected to a STM32 Nucleo board with supported firmware [Library Evaluation] tab is opened.

To start and stop data streaming, toggle the appropriate [Start] vertical tool bar.

or [Stop] button on the outer

The data coming from the connected sensor can be viewed selecting the [Data Table] tab on the inner vertical tool bar.

Figure 6. MEMS-Studio – Library Evaluation – Data Table

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MotionCP middleware library in X-CUBE-MEMS1 software expansion for STM32Cube
Step 4. Click on the [Carry Position] to open the dedicated application window. Figure 7. MEMS-Studio – Library Evaluation – Carry Position

Step 5.

Click on the [Save To File] to open the dataloging configuration window. Select the sensor and carry position data to be saved in the file. You can start or stop saving by clicking on the corresponding
button.

Figure 8. MEMS-Studio – Library Evaluation – Save To File

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MotionCP middleware library in X-CUBE-MEMS1 software expansion for STM32Cube

Step 6.

Data Injection mode can be used to send the previously acquired data to the library and receive the
result. Select the [Data Injection] tab on the vertical tool bar to open the dedicated view for this functionality.

Figure 9. MEMS-Studio – Library Evaluation – Data Injection

Step 7.

Click on the [Browse] button to select the file with the previously captured data in CSV format. The data will be loaded into the table in the current view. Other buttons will become active. You can click on:
[Offline Mode] button to switch the firmware offline mode on/off (mode utilizing the previously captured data).
[Start]/[Stop]/[Step]/[Repeat] buttons to control the data feed from MEMS-Studio to the library.

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References

References

All of the following resources are freely available on www.st.com. 1. UM1859: Getting started with the X-CUBE-MEMS1 motion MEMS and environmental sensor software
expansion for STM32Cube 2. UM1724: STM32 Nucleo-64 boards (MB1136) 3. UM3233: Getting started with MEMS-Studio

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Revision history

Table 5. Document revision history

Date

Version Changes

15-May-2017 1 Initial release.

25-Jan-2018 2 Added references to NUCLEO-L152RE development board and Table 3. Elapsed time (µs) algorithm.

20-Mar-2018 3 Updated Introduction, Section 2.1 MotionCP overview and Section 2.2.5 Algorithm performance.

Updated Figure 1. Example of sensor orientations, Figure 3. STM32 Nucleo vs phone orientation, 18-Feb-2019 4 Table 3. Elapsed time (µs) algorithm and Figure 4. STM32 Nucleo: LEDs, button, jumper.
Added X-NUCLEO-IKS01A3 expansion board compatiblity information.

Updated Introduction, Section 2.2.1: MotionCP library description and Section 2.2.5: Algorithm 25-Mar-2020 5 performance.
Added ARM Cortex-M7 architecture compatibility information.

01-Jul-2025

Updated Section Introduction, Section 2.1: MotionCP overview, Section 2.2.1: MotionCP library 6 description, Section 2.2.2: MotionCP APIs, Section 2.2.5: Algorithm performance,
Section 2.3: Sample application, Section 2.4: MEMS Studio application

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Contents
Contents
1 Acronyms and abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2 MotionCP middleware library in X-CUBE-MEMS1 software expansion for
STM32Cube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 2.1 MotionCP overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2 MotionCP library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2.1 MotionCP library description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2.2 MotionCP APIs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2.3 API flow chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2.4 Demo code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2.5 Algorithm performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3 Sample application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.4 MEMS Studio application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

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List of tables

List of tables

Table 1. Table 2. Table 3. Table 4. Table 5.

List of acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Algorithm performance data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Algorithm elapse time (µs) Cortex-M4, Cortex-M3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Algorithm elapse time (µs) Cortex-M33 and Cortex-M7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

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List of figures

List of figures

Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9.

Example of sensor orientations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 MotionCP API logic sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 STM32 Nucleo vs phone orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 STM32 Nucleo: LEDs, button, jumper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 MEMS-Studio – Connect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 MEMS-Studio – Library Evaluation – Data Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 MEMS-Studio – Library Evaluation – Carry Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 MEMS-Studio – Library Evaluation – Save To File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 MEMS-Studio – Library Evaluation – Data Injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

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UM2224
IMPORTANT NOTICE READ CAREFULLY STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, enhancements, modifications, and improvements to ST products and/or to this document at any time without notice. Purchasers should obtain the latest relevant information on ST products before placing orders. ST products are sold pursuant to ST’s terms and conditions of sale in place at the time of order acknowledgment. Purchasers are solely responsible for the choice, selection, and use of ST products and ST assumes no liability for application assistance or the design of purchasers’ products. No license, express or implied, to any intellectual property right is granted by ST herein. Resale of ST products with provisions different from the information set forth herein shall void any warranty granted by ST for such product. ST and the ST logo are trademarks of ST. For additional information about ST trademarks, refer to www.st.com/trademarks. All other product or service names are the property of their respective owners. Information in this document supersedes and replaces information previously supplied in any prior versions of this document.
© 2025 STMicroelectronics All rights reserved

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Documents / Resources

ST NUCLEO-F401RE Nucleo Development Board [pdf] User Manual
NUCLEO-F401RE, NUCLEO-U575ZI-Q, NUCLEO-L152RE, NUCLEO-F401RE Nucleo Development Board, NUCLEO-F401RE, Nucleo Development Board, Development Board, Board

References

User Manual

ST NUCLEO-F401RE Nucleo Development Board User Manual

NUCLEO-F401RE Nucleo Development Board

Specifications

Product Usage Instructions

MotionCP Library Overview

Implementation Requirements

Accessing Library Information

MotionCP APIs

Frequently Asked Questions (FAQ)

Q: Can I use the MotionCP library with non-ST MEMS
sensors?

Q: What is the required accelerometer data sampling frequency
for MotionCP library?

Documents / Resources

References

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