MAXREFDES101 USER ADOPTION GUIDE FOR MAX32664GWEB Jun 2019

MAXREFDES101 User Adoption Guide

Maxim Integrated 2

©2019 Maxim Integrated Products, Inc. All rights reserved.

Rev. 0.04

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MAXREFDES101 User Adoption Guide

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1. Introduction to MAXREFDES101

MAXREFDES101 is a unique evaluation and development platform in a wrist-worn wearable

form factor that demonstrates the functions of a wide range of Maxim’s products for

health-sensing applications. It integrates a PPG analog-front-end (AFE) sensor (MAX86141),

a biopotential AFE (MAX30001), a human body temperature sensor (MAX30205), a host

microcontroller (MAX32630), a power-management IC (MAX20303), along with a sensor

hub (MAX32664). MAX32664 is a sensor hub family with embedded firmware and

algorithms for wearables. It seamlessly enables customer desired sensor functionality,

including communication with Maxim’s optical sensor solutions and delivering raw or

calculated data to the outside world. This is achieved while keeping overall system power

consumption in check.

MAXREFDES101 system diagram is shown below:

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Figure 1: MAXREDES101 System Diagram

MAX30001ECG AFE

HostMicrocontroller

MAX32630

ARM CortexTM

M4F MCU

MAX30205

TEMPERATURE SENSOR

BMP280

BAROMETRIC PRESSURE

BMI160

ACCELEROMETER/GYRO

MAX20303

POWER MANAGEMENT IC

MAX30001ECG AFE

PAN1326B

BLUETOOTH/BLE

USB-C CONNECTOR

I2C

I2C

QSPIMX25U12835FZ2I-10G

32MB FLASH MEMORY

MAX32664

ARM CortexTM

M4F MCU

MAX86141

OPTICAL SENSOR

Sensor Board

Biometric Sensor Hub

I2C

UART

BootLoader

Microcontroller Board

I2C

HR Algorithm

KX122

3-AXISACCEL(optional)

SPI1

SPI0

SPI0

Display Sharp

LS013B7DH03SPI

Pushbutton 1

Pushbutton 2

Pushbutton 3

In this design, MAX32630 is used as the host controller. A display and three pushbuttons are

connected to the microcontroller. The sensor hub microcontroller is the MAX32664 which

has the pre-programmed wearable heart rate and SpO2 algorithms1. The MAX86141 optical

AFE sensor and the KX-122 accelerometer are connected to the sensor hub.

MAXREFDES101 hardware and software reference designs are available for Maxim

customers on Maxim’s product webpage and on the respective mbed OS webpages.

The protocol for communicating with the MAX32664 sensor hub is defined in the

MAX32664 User Guide.

1 MAX32664 has several variants. Please contact Maxim sales to find the part that best suits your algorithm needs.

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2. MAXREFDES101-based watch reference design

MAXREFDES101 EV-Kit software comes complete with the following:

- MAX32664 firmware with embedded health-sensing algorithm (Wrist Heart Rate

Monitor(WHRM))

- MAX32630 host firmware, which provides communication between MAX32664 and the

Windows or Android visualization/debugging application

- A Windows or Android GUI application for evaluation and debugging

PC GUI

MAX32630(uController

Host)

MAX32664(Embedded Algorithm)

Comms between MAX32664 and GUI

Wearable Heart Rate and Blood

Oxygen Monitoring(WHRM, WSpO2)

Command and controls for MAX32664

MAXREFDES101 Watch

Figure 2: MAXREFDES101 software components

MAXREFDES101 reference design can also be used by our customers to design their own

system, which may require a different set of software. An example design can be as follows:

uController Host

MAX32664(Embedded Algorithm)

Command and controls for MAX32664

Wearable Heart Rate and Blood

Oxygen Monitoring(WHRM, WSpO2)

Customer Wearable Design

Figure 3:Customer's wearable design software components

In this case, MAX32664 is now fully controlled by the embedded microcontroller. A typical

system diagram for a MAXREFDES101-based watch design will then look like the following:

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MAX30001ECG AFE

HostMicrocontroller

MAX32664B

ARM CortexTM

M4F MCU

MAX86141

OPTICAL SENSOR

Sensor Board

Biometric Sensor Hub

I2C

BootLoader

Customer Board for Watch

WHRM Algorithm

KX122

3-AXISACCEL(optional)

SPI1

Display

Pushbutton 1

Figure 4: Typical customer watch design based on MAXREFDES101

This reference design software includes:

- Sample host (microcontroller) software

- MAX32664 firmware algorithm (WHRM) binary

3. Sample host (microcontroller) software

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The sample host software consists of three modules:

- Watch GUI & controls

- SH Communications

- Algorithm Report using SH configured with MAX8614X

Host Software

SH Communications

Algorithm Report using SH(MAX8614X)

Watch GUI & Controls

Figure 5: Sample host software modules

3.1. Hardware abstraction in sample host software

The sample host controller software is layered to provide hardware abstraction. This

layered approach will allow most of the software modules to be cut and pasted into our

customer’s target platform. Hardware dependent modules may require modifications to

match your target microcontroller.

The sample host controller software is divided up into three layers:

1) The hardware libraries, which are the microcontroller specific code to support the hardware devices such as interrupts, I2C, and GPIOs.

2) The sensor hub communications layer, which include procedures to read/write data from/to the sensor hub, change the sensor hub mode to either application mode or bootloader mode, and to initialize the MAX32664 sensor hub.

3) The application layer, which has procedures for the user interface interactions to the display and pushbutton and procedures to stream processed data from the sensor hub.

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Peripheral Libraries

Sensor Hub Interface

Application Layer

User Interface

Sensor Hub CommunicationsSH MAX86141, Algorithm

UI DisplayUI Select Algo using

Pushbutton

SH Change Mode

SH Enable/Disable

SH Read/Write

MAX86141 Read/Write Register

MAX86141 Enable/Disable

Digital IO

SH Init Hw

Get WHRM Report Data

InterruptsSPII2CPushbuttonDisplay

Figure 6: Sample host software layered design

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3.2. Sample host software flowchart

We utilize MAXREFDES101 hardware (watch form factor) to demonstrate our sample

software. Below is the flowchart:

Update display

with HR data

Retrieve HR data from FIFO

Enable HR

Algorithm

START

InItialization:

MAX86141, KX-122

PushButton, Display,

Sensor Hub Communications

Figure 7: Sample host software flowchart

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4. Data Flow Diagram The drawing below is the Data Flow Diagram for the displaying of the data for the host software.

Display

FIFO Data from Sensor Hub

Parse HR data

Report FIFO Data

Sensor Hub Interface

Send Data to

Display

User Interface

Figure 8: Sample host software layered design

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5. Mbed code repository

The source code for the MAX32630 is located at: https://os.mbed.com/teams/MaximIntegrated/code/Host_Software_MAX32664GWEB_HR_wrist/ It is compatible w/ the .msbl file listed in the Compatibility section.

6. Display and Button Interface

6.1. Display

The watch display will display the user heart rate when turned on and strapped to the user wrist:

Figure 9: Heart Rate displayed

6.2. Software Reset Button When the upper right button is pressed twice, the software is reinitialized:

Figure 10: Top Right button pressed once.

6.3. Off Buttons

When the upper left button and the upper right button are both pressed for about thirteen seconds, the MAXREFDES101 will be turned off.

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Figure 11: MAXREFDES101 Off

7. Serial Interface

Plug in the USB-C cable to the MAXREFDES101. Use a serial terminal application such as Terra Term to connect to the USB Serial Device, 115200 baud, 8N1N.

7.1. Serial terminal data stream

After the serial terminal application is correctly connected, the heart rate, confidence, and algorithm status are displayed:

Figure 12: Serial terminal displays heart rate, confidence and status

7.2. Stopping the data stream

Enter the command “stop” or cut and paste “stop” into the terminal window and press <Enter>.

Figure 133: Serial terminal stopped

7.3. Enabling visibility of serial inputs

In the terminal window, type “set_host_echomode 1” and then press <Enter>.

Figure 144: Serial terminal echomode set to 1

7.4. Read a register from the MAX86141

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In the terminal window, type “get_reg ppgsensor 0xff” and then press <Enter>.

Figure 153: Register read command

7.5. Enable the data stream

In the terminal window, type “enable_measurement whrm” and then press <Enter>.

Figure 164: Streaming data enabled

7.6. Serial Command List and Description

stop stops the serial data streaming

enable_measurement whrm starts the serial data streaming

set_host_echomode [visible] visible=1: Enables the visibility of the user typing visible=0: Disables the visibility of the user typing

get_hub_fwversion Displays the sensor hub version.

get_host_opmode Displays whether the mode is APPMODE or BOOTLOADERMODE

set_host_opmode 1 Changes the mode to bootloader mode

get_reg ppgsensor [reg] reg = [0..0xff]: address of the register to display

set_reg ppgsensor [reg] [val] val=[0..0xff]: set the register to this value. reg=[0..0xff]: set the value of this register to [val].

get_cfg whrm aecenable 1: AEC is enabled 0: AEC is disabled

set_cfg whrm aecenable [enable]

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enable=1: enable AEC disable=0: disable AEC

get_cfg whrm scdenable 1: SCD is enabled 0: SCD is disabled

get_cfg whrm scdadjperiod period of time to adjust the target PD, 16-bit unsigned, seconds

set_cfg whrm scdadjperiod [period] period = [0..0XFFFF]: Period of time to adjust the target PD, 16-bit unsigned, seconds

get_cfg whrm scddebouncewin Displays the debounce for SCD, which is number of consecutive results of skin contact status to be reflected in the final output.

set_cfg whrm scddebouncewin [dbwin] dbwin=[0..0XFFFF]: The motion magnitude threshold for Motion Detector LSB=0.1g, 16-bit unsigned.

get_cfg whrm motionthreshold Displays the motion magnitude threshold for Motion Detector LSB=0.1g, 16-bit unsigned.

set_cfg whrm motionthreshold [threshold] threshold=[0..0XFFFF]: The motion magnitude threshold for Motion Detector, LSB=0.1g, 16-bit unsigned.

get_cfg whrm minpdcurrent Displays the minimum PD current, LSB=0.1mA, 16-bit unsigned.

set_cfg whrm minpdcurrent [mincurr] mincurr=[0..0XFFFF]: The minimum PD current, LSB=0.1mA, 16-bit unsigned.

get_cfg whrm pdconfig Displays the minimum PD configuration: 1=PD1, 2=PD2, 3=Both PD1&PD2

set_cfg whrm pdconfig [pdcfg] pdcfg: The PD configuration: 1=PD1, 2=PD2, 3=Both PD1&PD2.

8. Compatibility Matrix

Mbed MAX32664GWEB Sample Host Release

Host Notes .msbl application algorithm/driver file

3/25/19 Mbed Files at revision

3:b8989dab0f88 https://os.mbed.com/teams/MaximIntegrated/code/Host_Software_MAX32664GWEB_HR_EXTENDED/

Additional features added to the Heart Rate display program: serial commands, msbl flashing code,

9/1/18 MAX32664WGEZ_SmartSensor_HSP2_v1.8.3.msbl