System Board 6312
MAXREFDES100# Health Sensor Platform
Maxim MAXREFDES100# health sensor platform is an integrated sensor platform that
helps customers evaluate Maxim's complex and innovative medical and high-end
fitness solutions. The platform integrates one biopotential analog front-end solution
(MAX30003), one pulse oximeter and heart-rate sensor (MAX30101), two human
body temperature sensors (MAX30205), one 3-axis accelerometer, one 3D
accelerometer and 3D gyroscope, and one absolute barometric pressure sensor.
PC and Android applications are provided on the Design Resources tab to help you
get up and running quickly. The PC application provides a graphical user interface
(GUI) allowing you to configure and interact with all the sensors over a USB
connection. The Android application provides the ability to monitor sensor data over
BLE. Instructions for installing and running the applications are found on the details
tab.
The ARM mbed development environment is supported for developers who want to
customize the operation of the platform. The companion MAXREFDES100HDK#
programming adapter that ships with the platform provides driverless drag-and-drop
programming for firmware updates as well as a virtual UART interface and CMSISDAP compatible debugger. For more details on firmware development and source
code examples visit the MAX32620HSP platform page on the ARM mbed developer
site.
Features
Skin temperature
Heart rate
Biopotential measurement (ECG)
Motion
Rotation
Barometric pressure
Applications
Fitness devices
Clinical devices
Wearable devices
Maxim builds complex and innovative solutions for medical and high-end fitness
applications. These solutions are primarily stemming from multiple product lines within
Maxim. In order to help customers evaluate the features of these solutions quickly and
enable them with their designs, Maxim developed an integrated sensor platform called
"hSensor" Platform. With this platform, customers can evaluate our portfolio faster
and more easily for multiple use cases. The hSensor platform is also flexible to
accommodate our newer solutions in design, or on the roadmap.
The hSensor platform supports the measurement of motion, precision skin
temperature, and a variety of biopotential measurements, including
electrocardiography (ECG), electromyography (EMG), and electroencephalography
(EEG). In addition, the hSensor platform also supports a variety of reflective photo
plethysmography measurements including pulse oximetry and heart-rate (HR)
detection at three wavelengths, 880nm (infrared, IR), 660nm (red) and 537nm (green).
The platform supports GUI applications on Windows ®-based PCs and Android ®based devices for simple data collection and visualization. Both direct USB
connection (through a USB type C connector) and Bluetooth ® low energy (BLE) radio
are supported for configuration and data collections.
A direct-to-flash memory mode is supported for data collection. Flash memory read
using a USB connection is also implemented.
The microcontroller of the platform is programmed with firmware that manages the system,
controls the registers of all the devices on the platform, and communicates with the PC GUI. For
users who want to customize the firmware for the microcontroller, refer to the firmware
development guide for details: mbed (referenced as MAX32620HSP).
The following items are included in the reference design box:
MAXREFDES100# board: the health-sensor board
MAXREFDES100HDK# board: the development board for the MAXREFDES100#
sensor board
Battery holder: for the installation of CR2032-type coin-cell battery if a USB cable is
not used
Two ECG cables: users can solder these two ECG cables to the board for ECG
measurements
USB type-C cable: for the connection between a PC and the MAXREFDES100#
board
Micro-USB cable: for the connection between a PC and the
MAXREFDES100HDK# board
The following use cases can be evaluated using this platform:
1. Fitness Applications
Chest-based applications
Chest straps with HR
Chest straps with HR & ECG
Wrist-based applications
Smart watches with Optical HR
Ear-based applications
Headphones with Optical HR
2. Clinical applications
Chest-based applications
1 lead-ECG patch for Arrhythmia detection (ECG & HR only)
Skin temperature measurements
Finger-based applications
Optical SpO2 measurement
Ear-based applications
Optical HR & SpO2
Head-based applications
Optical HR & SpO2
Arm-based applications
Arm bands with ECG
As with all Maxim reference designs, the bill of materials (BOM), schematics, layout
files, Gerber files, firmware, and software are all available online.
System Diagram
Figure 1. The MAXREFDES100# Reference Design Block Diagram.
Detailed Hardware Description
The MAX32620 microcontroller lies at the center of the hSensor. The following
sensors are installed: MAX30003 biopotential analog front-end (AFE), MAX30205
human body temperature sensor, MAX30101 pulse oximeter and heart-rate sensor,
LIS2DH 3-axis accelerometer, LSM6DS3 3D accelerometer and 3D gyroscope, and
BMP280 absolute barometric pressure sensor.
Power Supplies
The hSensor platform can be powered by a USB connection or by a CR2032-type
coin cell battery. When both USB and coin cell are attached the power is drawn from
the USB due to MOSFET / Schottky diode at Q4. If a coin cell is attached without
USB the coin cell is used to power the hSensor platform.
The hSensor platform uses a MAX14720 PMIC for the majority of the power management. The PMIC
has internal programming such that a 3‐second button press at SW1 turns the device on. A 20‐
second press at SW2 turns the PMIC off.
The PMIC has a power-on configuration that provides 1.2V, 1.8V and VSYS
voltages. Here VSYS comes from SWOUT, which in turn comes from the battery or
USB through the PMIC pin SWIN. After power-up, the microcontroller configures the
PMIC for a boost voltage of 3.3V, which appears at the HVOUT pin.
While the PMIC provides the majority of power management there are some
additional power supply chips. The temperature sensors are powered by a MAX8880
LDO, which is powered by HVOUT (3.3V) and regulates this down to 2.5V. The
PMIC itself is fed by a MAX8881 3.3V LDO when the hSensor is attached to USB.
ESD protection is provided by the MAX3205, which attaches to all of the USB signals
except for DP/DM, which have ESD protection provided by the MAX32620.
Mode selection signals
The hSensor platform uses the USB type C connector for debug (programming) and
accessory signals. In some circumstances, these signals would contend with a USB
host, so there is circuity to isolate these signals as needed.
The isolation is done with MAX4741 low-voltage analog switches. These switches
are controlled by a combination of logic gates and MAX9064 single comparators.
The MAX9064 has an internal comparison voltage of 0.2V and two of them are used
to monitor the USB pins A5 and B5 (typically designated as CC/V CONN). The USB A5
and B5 pins have 5.1kΩ pulldowns on the HSP board, a USB cable has a 56kΩ
pullup on only pin A5 and a debug adapter board has 56kΩ pullups on both pin A5
and B5.
The following table indicates how the hSensor platform self-configures based on the
USB A5 and B5 pins.
USB Pin A5
USB Pin B5
Mode
Connection
Low
Low
Accessory
VIO and UART enabled by micro
Low
High
USB Cable
All accessory signals isolated
High
Low
High
High
Debug
SWD, RST, VIO and UART enabled
MAX32620 Microcontroller
The MAX32620 is a 32-bit ARM ® Cortex®-M4F (M4 plus floating point unit)
microcontroller, suited for emerging medical and fitness applications. The
architecture combines high-efficiency, signal-processing functionality with low cost,
and ease of use. The device features 4 powerful and flexible power modes. Built-in
dynamic clock gating and firmware controlled power gating minimize power
consumption for any application. Multiple SPI, UART, and I 2C serial interfaces, as
well as a 1-Wire ® master and USB, allow for interconnection to a wide variety of
external sensors. A four-input, 10-bit ADC with selectable reference is provided.
Refer to the MAX32620 data sheet for details and design resources including
evaluation kit, developing tools & user guides.
MAX30003 Biopotential AFE
The MAX30003 is a complete, biopotential AFE solution for wearable applications. It
offers high performance for clinical and fitness applications, with ultra-low power for
long battery life. The MAX30003 is a single biopotential channel providing ECG
waveforms and heart-rate detection.
The biopotential channel has ESD protection, EMI filtering, internal lead biasing, DC
leads-off detection, ultra-low power leads-on detection during standby mode, and
extensive calibration voltages for built-in self-test. Soft power-up sequencing ensures
no large transients are injected into the electrodes. The biopotential channel also
has high-input impedance, low noise, high CMRR, programmable gain, various lowpass and high-pass filter options, and a high resolution analog-to-digital converter
(ADC). The biopotential channel is DC coupled, can handle large electrode voltage
offsets, and has a fast recovery mode to quickly recover from overdrive conditions,
such as defibrillation and electrosurgery.
The MAX30003 interface is compatible with SPI/QSPI™/Micro-wire/DSP. In the
hSensor platform, the MAX30003 communicates with the MAX32620 microcontroller
through an SPI bus.
The MAX30003 is available in a 28-pin TQFN and 30-bump wafer-level package
(WLP), operating over the 0°C to +70°C commercial temperature range.
For users who want to connect the ECG cables for measurement, remove R6, R21,
R44, and R45 on the sensor board. Solder ECG cables on ECGP and ECGN pads
on the sensor board.
Refer to the MAX30003 data sheet for details.
MAX30205 Human Body Temperature Sensor
The hSensor board has two MAX30205 installed, one on the top side and one on the
bottom side.
The MAX30205 temperature sensor accurately measures temperature and provides
an overtemperature alarm/interrupt/shutdown output. This device converts the
temperature measurements to digital form using a high-resolution, sigma-delta ADC.
The accuracy of the MAX30205 meets the clinical thermometry specification of the
ASTM E1112 when soldered on the final PCB. Communication is through an I 2Ccompatible, 2-wire serial interface.
The I2C serial interface accepts standard write byte, read byte, send byte, and
receive byte commands to read the temperature data and configure the behavior of
the open-drain overtemperature shutdown output.
The MAX30205 features three address select lines with a total of 32 available
addresses. The sensor has a 2.7V to 3.3V supply-voltage range, low-600µA supply
current, and a lockup-protected I2C-compatible interface that make it ideal for
wearable fitness and medical applications.
In the hSensor platform, the top side MAX30205 (U2) I2C address is 0b1001-001x,
the bottom side MAX30205 (U12) I2C address is 0b1001-000x.
This device is available in an 8-pin TDFN package and operates over the 0°C to
+50°C temperature range.
Refer to the MAX30205 data sheet for details.
Quick Start Guide for PC Application
Download the latest MAXREFDES100# PC GUI program
MAXREFDES100SWxxx.zip and serial driver MAXREFDES100SerialDriverxxxx.zip
located at the MAXREFDES100# web page.
Required equipment:
MAXREFDES100# board
A PC with a spare USB port
One USB type A to C cable
Procedure
The MAXREFDES100# board is fully assembled and tested. Use the following steps
below to verify proper board operation.
1. Unzip the hSensor serial port driver MAXREFDES100SerialPortDriverxxxx.zip
to a local folder. MAXREFDES100SerialPortDriverxxxx.zip to a local folder.
2. Unzip the PC GUI program MAXREFDES100SWxxx.zip to a local folder and run
MAXREFDES100SWxxx.exe to install the program on the PC.
3. Run the GUI program and ignore the following pop up window. Click OK to
continue.
Figure 2. Connection Issue window.
4. Click Cancel button on the following pop up window:
Figure 3. Connection window 1.
5. The GUI program should appear as follow:
Figure 4. Hardware Not Connected window.
6. Connect the hSensor board to the PC with the USB A to C cable.
7. Press and hold the SW1 switch on the hSensor board for 3 seconds and then release. During this
time, the PC looks for the device driver for the hSensor if the Maxim hSensor serial driver has not
been installed on this computer.
8. Open the Device Manager window, the hSensor is enumerated as CDC Device as shown in the
following window:
Figure 5. Device Manager window 1.
9. Right click CDC DEVICE and then click Update Driver Software... to finish the driver installation. The
driver is located where MAXREFDES100SerialPortDriverxxxx.zip was unzipped.
10. After the driver installation is done, the hSensor is enumerated as a serial port and the Device
Manager should display as below:
Figure 6. Device Manager window 2.
11. Go back to the hSensor GUI program, click Device menu, and then click Connect menu item, the
GUI program should be connecting to the hSensor hardware. The following window should appear.
Check the status bar, verify the hardware is connected.
Figure 7. Home tab.
12. In the future sessions, launch the GUI program by clicking the Startmenu and
selecting the Maxim Integrated folder and then selecting Health Sensor Platform
software icon. The GUI should automatically connect to the sensor board. If a
connection screen pops up, select the right serial port number and click the Connect
button as shown below:
Figure 8. Connection window 2.
Detailed Software Description
The GUI program enables users to quickly configure and evaluate the sensors'
features. It also provide intuitive graphs for data collection and visualization.
The File menu lets a user exit the application.
The Device menu lets a user connect and disconnect the hSensor hardware from
the GUI program.
The Options menu lets a user show or hide the MAX30003 register names on the
GUI, load or save device register settings, and enable or disable Advanced tab.
The Logging menu lets a user log ECG, R-to-R, optical, and accelerometer sensor
data in a CSV file format.
The Help menu shows the program information.
Home Tab
TheHome tab sheet (Figure 7) displays the block diagram of the hSensor platform
hardware, it also provides quick links to navigate to other tab sheets.
Optical Tab
The Optical tab sheet (Figure 9) is used to configure the MAX30101 optical sensor
parameters. It includes the sensor mode configuration, sensor ADC configurations,
and LED settings. It also has graphs to show ADC codes and the LIS2DH
accelerometer measurements. Click Start Monitor button to plot optical and
acceleration measurements. Click Stop Monitor button to stop the measurements. .
Click Start Monitor button to plot optical and acceleration measurements. Click Stop
Monitor button to stop the measurements.
Figure 9. Optical tab.
Temperature Tab
The Temperature tab sheet (Figure 10) controls the two MAX30205 temperature
sensors on the top and bottom sides of the hSensor board.
Figure 10. Temperature tab.
ECG Channel Tab
The ECG Channel tab sheet (Figure 11) controls the MAX30003 ECG channel and Rto-R settings.
Figure 11. ECG Channel tab.
ECG MUX Tab
The ECG MUX tab sheet (Figure 12) controls the MAX30003 input multiplexers'
settings. A typical setting is shown below:
Figure 12. ECG MUX tab.
Plots Tab
The Plots tab sheet (Figure 13) displays MAX30003 ECG measurement values and
input MUX status.
Figure 13. Plots tab.
Flash Log Tab
The Flash Log tab sheet (Figure 14) allows users to configure data logging to flash
memory. The Read button reads the current configured settings from flash memory
and applies it to the UI. The Erase button clears the data-logging settings. The Write
button commits the data log settings to flash memory by selecting the desired logging
channels and parameters on this tab. This also clears any data values stored on the
flash memory. For optical, and MAX30003 settings, use the drop-down options on
their respective tabs. The Advanced button shows the raw command parameters
from the UI or settings read from flash memory. The Prefix and Suffix fields allow
users to execute custom commands. The Save to File button downloads the data
from the flash memory to one or more CSV files. The Write button and Save to File
button operations may require a long period of time to complete depending upon the
amount of data stored on the flash memory.
Figure 14. Flash Log tab.
Registers Tab
The Registers tab sheet (Figure 15) lists all the registers for the MAX30101,
MAX30205 (top), MAX30205 (bottom), MAX30003, MAX14720, and the LIS2DH. A
user can directly read or write the registers.
Figure 15. Registers tab.
Quick Start Guide for Android Application
The hSensor Android App is a GUI program running on an Android device. The
program collects hSensor data and graphically displays it on the device screen. The
program communicates with the hSensor hardware through Bluetooth 4.0 Low
Energy radio.
Required Equipment:
MAXREFDES100# board
Android device running at least version 4.4
Android device with Bluetooth 4.0 support
One CR2032 coin cell battery (optional)
A PC with a spare USB port (optional if battery powered)
One USB type A to C cable (optional if battery powered)
Procedure
1. Insert the CR2032 battery into the battery holder B1.
2. If no battery is available, connect the hSensor platform hardware to a PC or Mac
though a USB type C connector.
3. Press and release SW1 switch on the board. The red LED beside the switch
should flash.
4. Download the latest MAXREFDES100# Android app
MAXREFDES100_Androidxxx.zip located at the MAXREFDES100# web page.
Unzip it and install it on the device. The app requires Android 4.4 or later.
5. Tap the MAXREFDES100 icon to start the hSensor Android App.
Figure 16. Android Application Screenshot 1.
6. Tap the Scan button at the bottom of the screen. The scan lists all of the devices
currently advertising using Bluetooth 4.0.
7. Tap the MAXREFDES100 device in the list to connect to the hSensor platform
hardware.
Figure 17. Android Application Screenshot 2.
8. The following screen shows up.
Figure 18. Android Application Screenshot8.
hSensor Interaction:
The hSensor platform sensors are listed when the device is connected.
Temperature, accelerometer and pressure are shown. Heart-rate information can be
shown from the MAX30003 ECG device. ECG leads must be connected to the
hSensor platform in order to show a correct reading. After connecting the leads, click
the Start button on the screen. The platform starts sampling ECG R-to-R information
and displays the resulting heart rate on the screen.
Disconnecting
The hSensor device may be disconnected by pressing the DISCONNECT button
found at the top of the screen.
Firmware Description
The MAXREFDES100# firmware is based on an interrupt-driven design model. After
power-up, the microcontroller configures the power management device and sensors
to their default settings. The microcontroller then waits for remote procedure calls
(RPC) from GUI or Android application.
The following is the simplified firmware flowchart:
Figure 19. Firmware Flowchart V10.
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Android is a registered trademark of Google Inc.
ARM is a registered trademark and registered service mark and Cortex is a registered trademark of ARM Limited.
The Bluetooth word mark and logos are registered trademarks owned by Bluetooth SIG, Inc. and any use of such
marks by Maxim is under license.
QSPI is a trademark of Motorola, Inc.
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© 2016 Maxim Integrated