Maxim Integrated MAX32664 User manual

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MAX32664 User Guide
UG6806; Rev preliminary 1; 02/22
Abstract
The MAX32664 user guide provides flow charts, timing diagrams, GPIOs/pin usage, I2C interface protocol,
and annotated I2C traces between the host microcontroller and the MAX32664. Typical application uses
the MAX32664 as a low-power microcontroller in a sensor hub configuration to provide processed data
such as heart rate and SpO2.

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Table of Contents
Introduction..........................................................................................................................................44
MAX32664 Variants...............................................................................................................................55
Maxim Reference Designs with MAX32664............................................................................................ 98
MAXREFDES220#...............................................................................................................................98
MAXREFDES101#.............................................................................................................................109
MAX32664 GPIOs and RSTN Pin......................................................................................................... 1211
MAX32664 Bootup and Application Mode......................................................................................... 1312
MAX32664 Bootloader Mode ........................................................................................................ 1312
MAX32664 Application Mode........................................................................................................ 1312
Communications to the MAX32664 over I2C...................................................................................... 1413
Bit Transfer Process....................................................................................................................... 1413
I2C Write....................................................................................................................................... 1716
I2C Read ........................................................................................................................................ 1817
MAX32664 I2C Message Protocol Definition...................................................................................... 1918
MAX32664 I2C Annotated Application Mode Example....................................................................... 3831
I2C Commands to Flash the Application Algorithm ............................................................................ 4334
In-Application Programming of the MAX32664.................................................................................. 4837
MAX32664 APIs and Methods for Reset, Sleep, Status, Heartbeat ..................................................... 5039
Revision History................................................................................................................................. 5140

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List of Figures
Figure 1. MAX32664 block diagram. ........................................................................................................9
Figure 2. MAXREFDES101# block diagram..............................................................................................10
Figure 3. Pin connections between the host and the MAX32664............................................................12
Figure 4. Entering bootloader mode using the RSTN pin and the MFIO GPIO pin....................................13
Figure 5. Entering application mode using the RSTN pin and MFIO pin................................................... 14
Figure 6. I2C Write/Read data transfer from host microcontroller. ........................................................15
Figure 7. Sequence to enter bootloader mode....................................................................................... 45
Figure 8. Page number byte 0x44 from the .msbl file. ............................................................................45
Figure 9. Initialization vector bytes 0x28 to 0x32 from the .msbl file......................................................45
Figure 10. Authentication bytes 0x34 to 0x43 from the .msbl file...........................................................45
Figure 11. Send page bytes 0x4C to 0x205B from the .msbl file.............................................................. 46
Figure 12. Sequence to enter application mode.....................................................................................47
Figure 13. MAX32664 in-application programming flowchart. ...............................................................49
List of Tables
Table 1. MAX32664 Variants, Matching Algorithms, and Reference Designs ............................................5
Table 2. RSTN Pin and GPIOs Pins .......................................................................................................... 12
Table 3. Additional GPIOs Used on the MAX32664 for the MAXREFDES220# .........................................13
Table 4. Additional GPIOs Used on the MAX32664 for the MAXREFDES101# .........................................13
Table 5. Read Status Byte Value.............................................................................................................15
Table 6. MAX32664 I2C Message Protocol Definitions ........................................................................... 19
Table 7. Sensor Hub Status Byte ............................................................................................................ 35
Table 8. Output FIFO Format Definitions................................................................................................ 35
Table 10. MAX32664GWEA I2C Annotated Application Mode Example..................................................39
Table 11. MAX32664GWEB I2C Annotated Application Mode Example..................................................40
Table 12. MAX32664GWEC I2C Annotated Application Mode Example..................................................41
Table 13. MAX32664GWED I2C Annotated Application Mode Example.................................................. 43
Table 14. Annotated I2C Trace for Flashing the Application ...................................................................45
Table 15. MAX32664 I2C Message Protocol Definitions .........................................................................50

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Introduction
The MAX32664 is a pre-programmed microcontroller with firmware drivers and algorithms. Combined
with the appropriate sensor devices, the MAX32664 acts as a sensor hub to provide processed data to a
host device. This solution seamlessly enables customers to receive raw and/or calculated data from
Maxim’s optical sensor solutions, while keeping overall system power consumption in check. The tiny form
factor (1.6mm x 1.6mm 16-bump WLP) allows for integration into extremely small applications. The
MAX32664 is integrated into Maxim’s complete reference design solutions, which shortens the time to
market.
The MAX32664 is the same hardware as the MAX32660 but with a pre-programmed bootloader that
accepts in-application programming (IAP) of Maxim supplied algorithms and sensor drivers. The
MAX32664 provides a fast-mode, I2C slave interface to a microcontroller host. A second I2C interface is
dedicated to communicating with sensors.
For further details on memory, register mapping, system clocks, reset, power management,
GPIOs/alternate functions, DMAcontroller, UART, RTC, timers, WDT, I2C, and SPI, see the MAX32660 User
Guide.
For ordering information, mechanical and electrical characteristics, and the pinout for the MAX32664
family of devices, refer to the MAX32664 data sheet.
For information on the Arm® Cortex®-M4 with FPU core, refer to the Cortex-M4 with FPU Technical
Reference Manual.
Arm is a registered trademark and registered service mark of Arm Limited.
Cortex is a registered trademark of Arm Limited.

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MAX32664 Variants
The MAX32664 is pre-programmed with bootloader software that accepts in-application programming of
Maxim application code which consists of algorithms and the associated sensor driver. The MAX32664 is
used as a sensor hub controller.
The algorithm/application code provides processed and/or raw data through the I2C interface. Several
variants of the MAX32664 exist based on the target application. These variants come pre-programmed
with a bootloader that only accepts the matching encryption keys for the part (e.g., the MAX32664GWEA
bootloader is pre-programmed with the A encryption key, reference designs are programmed with Z
keying, etc.). Designers should use the table below in order to select the correctly keyed part..
Table 1. MAX32664 Variants, Matching Algorithms, and Reference Designs
PART NUMBER
APPLICATION ALGORITHM/FIRMWARE
BOOTLOADER
KEY
MAXIM REFERENCE
DESIGN
MAX32664GWEA
MaximFast: Maxim Integrated®finger-based heart-
rate and SpO2monitoring algorithm (100Hz
sampling). The MaximFast algorithm is compatible
with the sensor hub combination of the
MAX3244664GWEA, MAX30101 AFE, and KX-122
accelerometer. It is recommended, but not
mandatory, to use an accelerometer with the
MaximFast algorithm. Do not enable the
accelerometer if there is no accelerometer in your
design. If the KX-122 accelerometer is not installed
in the design and external accelerometer data is
supplied, then the accelerometer should use the
100Hz sampling rate.
Automatic gain control (AGC) for MaximFast. If the
AGC is enabled, the LED currents and pulse width
are automatically determined by the algorithm. If
the AGC is not enabled, the LED currents and pulse
width registers should be configured by the host
software.
A
MAXREFDES220#

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PART NUMBER
APPLICATION ALGORITHM/FIRMWARE
BOOTLOADER
KEY
MAXIM REFERENCE
DESIGN
MAX32664GWEB
The Wearable heart-rate monitoring (WHRM)
algorithm (25Hz sampling). The WHRM algorithm is
configured to use LED1 and Photodiode (PD) 1
or/and 2, and it is compatible with the sensor hub
combination of the MAX32664GWEB, MAX86141
AFE, and KX-122 accelerometer. It is mandatory to
use accelerometer the KX-122 accelerometer or
external accelerometer data with the WHRM
algorithm to detect and compensate motion. If the
KX-122 accelerometer is not connected to
MAX32664, then external accelerometer data
should be supplied at the 25Hz sampling rate.
The Automatic Exposure Control and Skin Control
Detection (AEC-SCD) of WHRM (AEC-SCD is included
in the WHRM algorithm). If AEC-SCD is enabled , the
LED current, pulse width and sample rate are
automatically determined by the algorithm. If AEC-
SCD is not enabled, the LED current, LED current
range, pulse width, and ADC range registers should
be configured by the host software.
B
MAXREFDES101#

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PART NUMBER
APPLICATION ALGORITHM/FIRMWARE
BOOTLOADER
KEY
MAXIM REFERENCE
DESIGN
MAX32664GWEC
The Wearable Heart-Rate Monitoring (WHRM)
algorithm (25Hz sampling). The WHRM algorithm is
configured to use LED1 (Green) and Photodiode 1
or/and 2, and it is compatible with the sensor hub
combination of the MAX32664GWEB, MAX86141
AFE, and KX-122 accelerometer. It is mandatory to
use accelerometer the KX-122 accelerometer or
external accelerometer data with the WHRM
algorithm to detect and compensate motion. If the
KX-122 accelerometer is not connected to
MAX32664 then the external accelerometer data
should be supplied at the 25Hz sampling rate.
The Automatic Exposure Control and Skin Control
Detection (AEC-SCD) of WHRM (AEC-SCD is included
in the WHRM algorithm). If AEC-SCD is enabled, the
LED current, pulse width and sample rate are
automatically determined by the algorithm. If AEC-
SCD is not enabled, the LED current, LED current
range, pulse width, and ADC range registers should
be configured by the host software.
The Wearable Oxygen Saturation (WSpO2)
algorithm (25Hz sampling). The WSpO2 algorithm is
configured to use LED2 (IR) and LED3 (Red) and
Phot-diode 1 or 2, and it’s compatible with the
sensor hub combination of the MAX32664GWEB,
MAX86141 AFE, and KX-122 accelerometer. It is
mandatory to use an accelerometer with the
WSpO2 algorithm to detect motion. If the KX-122
accelerometer is not connected to MAX32664
external accelerometer data should be supplied,
then external accelerometer should use the 25Hz
sampling rate.
The Automatic Gain Control (AGC) of WSpO2. If AGC
is enabled, the LED currents and ADC range are
automatically determined by the algorithm. If the
AGC is not enabled, the LED currents, pulse width
and ADC range registers should be configured by the
host software.
C
MAXREFDES101 with
SpO2 LED Board

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PART NUMBER
APPLICATION ALGORITHM/FIRMWARE
BOOTLOADER
KEY
MAXIM REFERENCE
DESIGN
MAX32664GWED
The finger-based Blood Pressure Trending (BPT),
heart rate and SpO2monitoring algorithm (100Hz
Sampling).
The algorithm is compatible with the sensor hub
combination of the MAX32664GWED and
MAX30101 AFE. No accelerometer is required for
this algorithm.
The BPT algorithm includes Automatic gain control
to adjust LED currents.
Prior to running the algorithm, a calibration
procedure is required to determine blood pressure
and SpO2calibration coefficients.
Automatic gain control (AGC). If the AGC is enabled,
the LED currents and pulse width are automatically
determined by the algorithm. If the AGC is not
enabled, the LED currents and pulse width registers
should be configured by the host software.
D
MAXREFDES220#
MAX32664GWEZ
Z-keyed algorithm/firmware of the above which
may be used to in-application program the Maxim
Integrated reference designs listed or for boards
that use the MAX32664GWEZ.
MAXREFDES220#
MAXREFDES101#
For all the MAX32664 parts, the algorithm (.msbl file) with the corresponding bootloader key must be
downloaded, and these parts must be programmed using the in-application programming feature of the
bootloader. The MAX32664 is only pre-programmed with the bootloader software.
Maxim Integrated is a trademark of Maxim Integrated Products, Inc.

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Maxim Reference Designs with MAX32664
Maxim provides multiple reference designs to its customers to enable quick and effective adoption of
MAX32664 and fastest time to market. For detailed schematics, refer to the user guide of each reference
design.
MAXREFDES220#
The MAXREFDES220# reference design provides everything you need to quickly prototype your product
to measure finger-based heart rate and blood oxygen saturation level (SpO2).
SENSOR HUB DRIVER FIRMWARE
DIGITAL SIGNAL PROCESSING
ALGORITHMS FOR
HEART RATE AND SPO2
MAX30101
PULSE OXIMETER
AND HEART-RATE
SENSOR
KX122-1037
3-AXIS
ACCELEROMETER
MAXREFDES220
FINGER HEART RATE AND PULSE OXIMETER SMART SENSOR
MAX32630FTHR
(HOST)
SENSOR
PLATFORM
COMMANDS
SECURE FIRMWARE BOOTLOADER
MAX32664(A)
BIOMETRIC SENSOR HUB
HEART RATE DATA
SPO2 DATA
ENCRYPTED .MSBL
APPLICATION
ALGORITHM/FIRMWARE
DOWNLOAD
SLAVE
I2C
SENSOR I2C
USB PC
GUI
Figure 1. MAX32664 block diagram.
The MAXREFDES220# solution, which includes the MAX30101 and the MAX32664, provides an integrated
hardware and software solution for finger-based applications. The MAX32664 is used as a sensor hub to
collect data from the MAX30101 analog front end (AFE). The reference design also includes a tri-axis
accelerometer (KX-122) to compensate for motion artifacts. (Accelerometer support in the
MAXREFDES220# is optional.)
The MAX32630FTHR is used as a sample host is included in MAXREFDES220# reference design.

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MAXREFDES101#
The 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.
MAX30001
ECG AFE
MAX32630
ARM CortexTM
M4F MCU
MAX30205
TEMPERATURE SENSOR
BMP280
BAROMETRIC PRESSURE
BMI160
ACCELEROMETER/GYRO
MAX20303
POWER MANAGEMENT IC
MAX30001
ECG AFE
PAN1326B
BLUETOOTH/BLE
USB-C CONNECTOR
I2C
I2C
QSPI
MX25U12835FZ2I-10G
32MB FLASH MEMORY
MAX32664
BIOMETRIC SENSOR HUB
MAX86140
OPTICAL
SENSOR
SENSOR BOARD
HEART RATE SENSOR HUB
I2C
UART BootLoader
MICROCONTROLLER BOARD
I2C
Application Code
Driver Firmware and
HR Algorithm
KX122
3-AXIS
ACCEL
(optional)
SPI1
SPI0
SPI0
Figure 2. MAXREFDES101# block diagram.
This second-generation health sensor platform (a follow-on to the MAXREFDES100#) integrates a PPG AFE
sensor (MAX86141), a biopotential AFE (MAX30001), a human body temperature sensor (MAX30205), a
microcontroller (MAX32630), a power-management IC (MAX20303), and a 6-axis
accelerometer/gyroscope. The complete platform includes a watch enclosure and a biometric sensor hub
with an embedded application code for heart-rate algorithm and AFE drivers (MAX32664)an embedded
heart-rate algorithm (MAX32664). Algorithm output and sensorraw data can be streamed through
Bluetooth® to an Android® application or PC GUI for demonstration, evaluation, and customized
development.