Maxim Integrated MAX32664 User manual

Maxim Integrated Page 1 of 52
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

Maxim Integrated Page 8 of 52
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.

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Android is a registered trademark of Google Inc.
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.

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MAX32664 GPIOs and RSTN Pin
To control and communicate with the MAX32664, the RSTN pin and GPIOs P0.1, P0.2, P0.3 of the
MAX32664 are connected to the host as pictured in Figure 3Figure 3.
Figure 3. Pin connections between the host and the MAX32664.
The RSTN pin is used in conjunction with the GPIO P0.1 MFIO pin to control whether the MAX32664 starts
up in Application mode or Bootloader mode. While in application mode, the MFIO pin can be configured
to provide an interrupt signal to the host.
The host acts an I2C master to communicate with the MAX32664. GPIO P0.2 is used as the SCL line and
GPIO P0.3 is used as the SDA line.
Table 2. RSTN Pin and GPIOs Pins
MAX32664
DESCRIPTION
DIRECTION FROM THE MAX32664 SIDE
Pin RSTN
Reset_N
Input
GPIO P0.1
GPIO MFIO interrupt to host, wake from host,
bootloader/application on powerup,
Input/Output
GPIO P0.2
I2C0_Host SCL
Input
GPIO P0.3
I2C0 Host SDA
Input/Output
Variations of the MAX32664 use additional GPIO pins in order to communicate and control sensor devices.
For example, in the MAXREFDES220#, the additional GPIOs listed in Table 3 are used to control the sensors
used.

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Table 3. Additional GPIOs Used on the MAX32664 for the MAXREFDES220#
MAX32664
DESCRIPTION
DIRECTION FROM THE MAX32664 SIDE
GPIO P0.6
KX122 ACCEL Interrupt
Input
GPIO P0.7
MAX30101 Interrupt
Input
GPIO P0.8
MAX30101, KX122 I2C1_SCL
Output
GPIO P0.9
MAX30101, KX122 I2C1_SDA
Input/Output
Table 4. Additional GPIOs Used on the MAX32664 for the MAXREFDES101#
MAX32664
DESCRIPTION
DIRECTION FROM THE MAX32664 SIDE
GPIO P0.0
KX122 ACCEL Select
Output
GPIO P0.4
SPI MISO: MAX86141, KX122
Input
GPIO P0.5
SPI MOSI: MAX86141, KX122
Output
GPIO P0.6
SPI CLK: MAX86141, KX122
Output
GPIO P0.7
MAX86141 Select
Output
GPIO P0.8
MAX86141 Interrupt
Input
GPIO P0.9
KX122 Interrupt
Input
MAX32664 Bootup and Application Mode
The MAX32664 is programmed to enter either bootloader mode or application mode at the start-up based
on the state of the MFIO pin.
Variations of the MAX32664 part are pre-programmed with the different algorithms and application
firmware. Check with your Maxim representative.
MAX32664 Bootloader Mode
The MAX32664 enters bootloader mode based on the sequencing of the RSTN pin and the MFIO pin. The
necessary sequence is as follows:
•Set the RSTN pin low for 10ms.
•While RSTN is low, set the MFIO pin to low (MFIO pin should be set low at least 1ms before RSTN
pin is set high).
•After the 10ms has elapsed, set the RSTN pin high.
•After an additional 50ms has elapsed, the MAX32664 is in bootloader mode.
Figure 4. Entering bootloader mode using the RSTN pin and the MFIO GPIO pin.
MAX32664 Application Mode
The MAX32664 enters application mode based on the sequencing of the RSTN pin and the MFIO pin. The
necessary sequence is as follows:

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•Set the RSTN pin low for 10ms.
•While RSTN is low, set the MFIO pin to high.
•After the 10ms has elapsed, set the RSTN pin high. (MFIO pin should be set high at least 1ms
before RSTN pin is set high).
•After an additional 50ms has elapsed, the MAX32664 is in application mode and the application
performs its initialization of the application software..
•After ~1 second from when the RSTN was set to high, the application completes the initialization
and the device is ready to accept I2C commands
Figure 5. Entering application mode using the RSTN pin and MFIO pin.
Communications to the MAX32664 over I2C
The host communicates to the MAX32664 through the I2C bus. The MAX32664 uses 0xAA as the I2C 8-bit
slave write address and 0xXAB is used as the I2C 8-bit slave read address. The maximum I2C data rate
supported is 3400 Kbps.
Bit Transfer Process
Both SDA and SCL signals are open-drain circuits. Each has an external pullup resistor that ensures each
circuit is high when idle. The I2C specification states that during data transfer, the SDA line can change
state only when SCL is low, and that SDA is stable and able to be read when SCL is high. Typical I2C
write/read transactions are shown in Figure 6.

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Figure 6. I2C Write/Read data transfer from host microcontroller.
The read status byte is an indicator of the success or failure of the Write Transaction. The read status byte
must be accessed after each write transactionto the device. This ensures that write transaction processing
is understood and any errors in the device command handling can be corrected. The value of the read
status byte is summarized in Table 54.
Table 54. Read Status Byte Value
STATUS BYTE
VALUE
DESCRIPTION
0x00
SUCCESS. The write transaction was successful.
0x01
ERR_UNAVAIL_CMD. Illegal Family Byte and/or Command Byte was used.
0x02
ERR_UNAVAIL_FUNC. This function is not implemented.
0x03
ERR_DATA_FORMAT. Incorrect number of bytes sent for the requested Family Byte.
0x04
ERR_INPUT_VALUE. Illegal configuration value was attempted to be set.
0x05
ERR_TRY_AGAIN. Device is busy. Try again.
0x80
ERR_BTLDR_GENERAL. General error while receiving/flashing a page during the bootloader
sequence.
0x81
ERR_BTLDR_CHECKSUM. Checksum error while decrypting/checking page data.
0x82
ERR_BTLDR_AUTH. Authorization error.
0x83
ERR_BTLDR_INVALID_APP. Application not valid.
0xFF
ERR_UNKNOWN. Unknown Error.

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I2C Write
The process for an I2C write data transfer is as follows:
1. The bus master indicates a data transfer to the device with a START condition.
2. The master transmits one byte with the 7-bit slave address (most significant 7 bits of the 8-bit
address) and a single write bit set to zero. The eight bits to be transferred as a slave address for
the MAX32664 is 0xAA for a write transaction.
3. During the next SCL clock following the write bit, the master releases SDA. Duringthis clock period,
the device responds with an ACK by pulling SDA low.
4. The master senses the ACK condition and begins to transfer the Family Byte. The master drives
data on the SDA circuit for each of the eight bits of the Family byte, and then floats SDA during
the ninth bit to allow the device to reply with the ACK indication.
5. The master senses the ACK condition and begins to transfer the Index Byte. The master drives
data on the SDA circuit for each of the eight bits of the Index byte, and then floats SDA during the
ninth bit to allow the device to reply with the ACK indication.
6. The master senses the ACK condition and begins to transfer the Write Data Byte 0. The master
drives data on the SDA circuit for each of the eight bits of the Write Data Byte 0, and then floats
SDA during the ninth bit to allow the device to reply with the ACK indication.
7. The master senses the ACK condition and can begin to transfer another Write Data Byte if
required. The master drives data on the SDA circuit for each of the eight bits of the Write Data
Byte, and then floats SDA during the ninth bit to allow the device to reply with the ACK indication.
If another Write Data Byte is not required, the master indicates the transfer is complete by
generating a STOP condition. A STOP condition is generated when the master pulls SDA from a
low to high while SCL is high.
8. The master waits for a period of CMD_DELAY (2 m60µsec) for the device to have its data ready.
9. The master indicates a data transfer to a slave with a START condition.
10. The master transmits one byte with the7-bit slave address and a single write bit set to one. This
is an indication from the master of its intent to read the device from the previously written
location defined by the Family Byte and the Index Byte. The master then floats SDA and allows
the device to drive SDA to send the Status Byte. The Status Byte reveals the success ofthe previous
write sequence. After the Status Byte is read, the master drives SDA low to signal the end of data
to the device.
11. The master indicates the transfer is complete by generating a STOP condition.
12. After the completion of the write data transfer, the Status Byte must be analyzed to determine if
the write sequence was successful and the device has received the intended command.

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I2C Read
The process for an I2C read data transfer is as follows:
1. The bus master indicates a data transfer to the device with a START condition.
2. The master transmits one byte with the 7-bit slave address and a single write bit set to zero. The
eight bits to be transferred as a slave address for the MAX32664 is 0xAA for a write transaction.
This write transaction precedes the actual read transaction to indicate to the device what section
is to be read.
3. During the next SCL clock following the write bit, the master releases SDA. Duringthis clock period,
the device responds with an ACK by pulling SDA low.
4. The master senses the ACK condition and begins to transfer the Family Byte. The master drives
data on the SDA circuit for each of the eight bits of the Family byte, and then floats SDA during
the ninth bit to allow the device to reply with the ACK indication.
5. The master senses the ACK condition and begins to transfer the Index Byte. The master drives
data on the SDA circuit for each of the eight bits of the Index byte, and then floats SDA during the
ninth bit to allow the device to reply with the ACK indication.
6. The master senses the ACK condition and begins to transfer the Write Data Byte if necessary for
the read instruction. The master drives data on the SDA circuit for each of the eight bits of the
Write Data byte, and then floats SDA during the ninth bit to allow the device to reply with the ACK
indication.
7. The master indicates the transfer is complete by generating a STOP condition.
8. The master waits for a period of CMD_DELAY (2 msec60µs) for the device to have its data ready.
9. The master indicates a data transfer to a slave with a START condition.
10. The master transmits one byte with the 7-bit slave address and a single write bit set to one. This
is an indication from the master of its intent to read the device from the previously written
location defined by the Family Byte and the Index Byte. The master then floats SDA and allows
the device to drive SDA to send the Status Byte. The Status Byte reveals the success of the previous
write sequence. After the Status Byte is read, the master drives SDA low to acknowledge the byte.
11. The master floats SDA and allows the device to drive SDA to send Read Data Byte 0. After Read
Data Byte 0 is read, the master drives SDA low to acknowledge the byte.
12. The master floats SDA and allows the device to drive SDA to send the Read Data Byte N. After
Read Data Byte N is read, the master drives SDA low to acknowledge the Read Data Byte N. This
process continues until the device has provided all the data that the master expects based upon
the Family Byte and Index Byte definition.
13. The master indicates the transfer is complete by generating a STOP condition.

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MAX32664 I2C Message Protocol Definition
Table 65 defines the I2C message protocol for the MAX32664.
Table 56. MAX32664 I2C Message Protocol Definitions
HOST COMMAND
MAX32664
FAMILY NAME
DESCRIPTION
FAMILY
BYTE
INDEX
BYTE
WRITE BYTES
RESPONSE BYTES
Read Sensor
Hub Status
Read sensor hub
status
(MAX32664GWEA,
MAX32664GWEB,
MAX32664GWEC,
MAX32664GWED)
0x00
0x00
-
Err0[0]: 0 = No Error; 1 = Sensor
Communication Problem
Err1[0]: Not used
Err2[0]: Not used
DataRdyInt[3]: 0 = FIFO below
threshold; 1 = FIFO filled to threshold
or above.
FifoOutOvrInt[4]: 0 = No FIFO
overflow; 1 = Sensor Hub Output FIFO
overflowed, data lost.
FifoInOvrInt[5]: 0 = No FIFO overflow;
1 = Sensor Hub Input FIFO overflowed,
data lost.
DevBusy[6]: 0 = Sensor Hub ready; 1 =
Sensor Hub is busy processing.
See Table 76 for the for the bit field
table.
Device Mode
Select the device
operating mode.
The application must
implement this.
(MAX32664GWEA,
MAX32664GWEB,
MAX32664GWEC,
MAX32664GWED)
0x01
0x00
0x00: Exit bootloader mode,
Enter application mode.
0x02: Reset.
0x08: Enter bootloader
mode.
-
Device Mode
Read the device
operating mode.
(MAX32664GWEA,
MAX32664GWEB,
MAX32664GWEC,
MAX32664GWED)
0x02
0x00
-
0x00: Application operating mode.
0x08: Bootloader operating mode.

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HOST COMMAND
MAX32664
FAMILY NAME
DESCRIPTION
FAMILY
BYTE
INDEX
BYTE
WRITE BYTES
RESPONSE BYTES
Set Output
Mode
Set the output format
of the sensor hub.
(MAX32664GWEA,
MAX32664GWEB,
MAX32664GWEC,
MAX32664GWED)
0x10
0x00
0x00: Pause (no data)
0x01: Sensor Data
0x02: Algorithm Data
0x03: Sensor Data and
Algorithm Data
0x04: Pause (no data)
0x05: Sample Counter byte,
Sensor Data
0x06: Sample Counter byte,
Algorithm Data
0x07: Sample Counter byte,
Sensor Data and Algorithm
Data
-
Set Output
Mode
Set the threshold for
the FIFO interrupt
bit/pin.
The MFIO pin is used
as the interrupt and
the host should
configure this pin as
an input interrupt
pin. The status bit
DataRdyInt is set
when this threshold
is reached.
(MAX32664GWEA,
MAX32664GWEB,
MAX32664GWEC,
MAX32664GWED)
0x10
0x01
0x01 to 0xFF: Sensor Hub
Interrupt Threshold for FIFO
almost full.
-
Read Output
Mode
READ the output
format of the sensor
hub.
(MAX32664GWEA,
MAX32664GWEB,
MAX32664GWEC,
MAX32664GWED)
0x11
0x00
0x00: Pause (no data)
0x01: Sensor Data
0x02: Algorithm Data
0x03: Sensor Data and Algorithm Data
0x04: Pause (no data)
0x05: Sample Counter byte, Sensor
Data
0x06: Sample Counter byte, Algorithm
Data
0x07: Sample Counter byte, Sensor
Data and Algorithm Data