Hexiwear is powered by a Kinetis K64 microcontroller based on the ARM Cortex-M4 core. Another Kinetis wireless MCU, the KW40Z, provides Bluetooth Low Energy connectivity. Hexiwear also integrates a wide variety of sensors, as well as a user interface consisting of a 1.1" 96px x 96px full color OLED display and six capacitive buttons with haptic feedback.
- Eye-catching Smart Watch form factor with powerful, low power Kinetis K6x MCU and 6 on-board sensors.
- Designed for wearable applications with the onboard rechargeable battery, OLED screen and onboard sensors such as optical heart rate, accelerometer, magnetometer and gyroscope.
- Designed for IoT end node applications with the onboard sensor's such as temperature, pressure, humidity and ambient light.
- Flexibility to let you add the sensors of your choice nearly 200 additional sensors through click boards.
- Main MCU: NXP Kinetis K64x (ARM Cortex-M4, 120 MHz, 1M Flash, 256K SRAM)
- Wireless MCU: NXP Kinetis KW4x (ARM Cortex-M0+, Bluetooth Low Energy & 802.15.4 radio)
- 6-axis combo Accelerometer and Magnetometer NXP FXOS8700
- 3-Axis Gyroscope: NXP FXAS21002
- Absolute Pressure sensor NXP MPL3115
- Li-Ion/Li-Po Battery Charger NXP MC34671
- Optical heart rate sensor Maxim MAX30101
- Ambient Light sensor, Humidity and Temperature sensor
- 1.1" full color OLED display
- Haptic feedback engine
- 190 mAh 2C Li-Po battery
- Capacitive touch interface
- RGB LED
For more information about the K64F SoC and Hexiwear board:
- K64F Website
- K64F Datasheet
- K64F Reference Manual
- Hexiwear Website
- Hexiwear Fact Sheet
- Hexiwear Schematics
The hexiwear/mk64f12 board variant supports the following hardware features:
| Interface | Controller | Driver/Component |
|---|---|---|
| NVIC | on-chip | nested vector interrupt controller |
| SYSTICK | on-chip | systick |
| PINMUX | on-chip | pinmux |
| GPIO | on-chip | gpio |
| I2C | on-chip | i2c |
| WATCHDOG | on-chip | watchdog |
| ADC | on-chip | adc |
| PWM | on-chip | pwm |
| UART | on-chip | serial port-polling; serial port-interrupt |
| FLASH | on-chip | soc flash |
| SENSOR | off-chip | fxos8700 polling; fxos8700 trigger; fxas21002 polling; fxas21002 trigger; max30101 polling |
| RNGA | on-chip | entropy; random |
The default configuration can be found in the defconfig file:
:zephyr_file:`boards/nxp/hexiwear/hexiwear_mk64f12_defconfig`
Other hardware features are not currently supported by the port.
The K64F SoC has five pairs of pinmux/gpio controllers.
| Name | Function | Usage |
|---|---|---|
| PTA29 | GPIO | LDO_EN |
| PTB0 | I2C0_SCL | I2C / MAX30101 |
| PTB1 | I2C0_SDA | I2C / MAX30101 |
| PTB12 | GPIO | 3V3B EN |
| PTB16 | UART0_RX | UART Console |
| PTB17 | UART0_TX | UART Console |
| PTC8 | GPIO / PWM | Red LED |
| PTC9 | GPIO / PWM | Green LED |
| PTC10 | I2C1_SCL | I2C / FXOS8700 / FXAS21002 |
| PTC11 | I2C1_SDA | I2C / FXOS8700 / FXAS21002 |
| PTC14 | GPIO | Battery sense enable |
| PTC18 | GPIO | FXAS21002 INT2 |
| PTD0 | GPIO / PWM | Blue LED |
| PTD13 | GPIO | FXOS8700 INT2 |
| PTE24 | UART4_RX | UART BT HCI |
| PTE25 | UART4_TX | UART BT HCI |
Note
To enable battery sensing, you will need to enable the en_bat_sens regulator in Devicetree. Similarly, to enable devices connected to the 1V8 or 3V3 power rails (sensors), you will need to enable the en_ldo and en_3v3b regulators in Devicetree.
The K64F SoC is configured to use the 12 MHz external oscillator on the board with the on-chip PLL to generate a 120 MHz system clock.
The K64F SoC has six UARTs. One is configured for the console, another for BT HCI, and the remaining are not used.
Build and flash applications as usual (see build_an_application and application_run for more details).
A debug probe is used for both flashing and debugging the board. This board is configured by default to use the opensda-daplink-onboard-debug-probe, but because Segger RTT is required for a console on KW40Z, we recommend that you reconfigure the board for the opensda-jlink-onboard-debug-probe.
Note
OpenSDA is shared between the K64 and the KW40Z via switches, therefore only one SoC can be flashed, debugged, or have an open console at a time.
Install the jlink-debug-host-tools and make sure they are in your search path.
Follow the instructions in opensda-jlink-onboard-debug-probe to program the OpenSDA J-Link Generic Firmware for V2.1 Bootloader. Check that switches SW1 and SW2 are on, and SW3 and SW4 are off to ensure K64F SWD signals are connected to the OpenSDA microcontroller.
Install the pyocd-debug-host-tools and make sure they are in your search path.
Follow the instructions in opensda-daplink-onboard-debug-probe to program the OpenSDA DAPLink Hexiwear Firmware. Check that switches SW1 and SW2 are on, and SW3 and SW4 are off to ensure K64F SWD signals are connected to the OpenSDA microcontroller.
Add the arguments -DBOARD_FLASH_RUNNER=pyocd and -DBOARD_DEBUG_RUNNER=pyocd when you invoke west build to override the default runner from J-Link to pyOCD:
Regardless of your choice in debug probe, we will use the OpenSDA microcontroller as a usb-to-serial adapter for the serial console.
Connect a USB cable from your PC to CN1.
Use the following settings with your serial terminal of choice (minicom, putty, etc.):
- Speed: 115200
- Data: 8 bits
- Parity: None
- Stop bits: 1
Here is an example for the hello_world application.
Open a serial terminal, reset the board (press the T4 button), and you should see the following message in the terminal:
***** Booting Zephyr OS v1.14.0-rc1 *****
Hello World! hexiwearHere is an example for the hello_world application.
Open a serial terminal, step through the application in your debugger, and you should see the following message in the terminal:
***** Booting Zephyr OS v1.14.0-rc1 *****
Hello World! hexiwearThe K64 can support Zephyr Bluetooth host applications when you configure the KW40Z as a Bluetooth controller.
- Download and install the KW40Z Connectivity Software. This package contains Bluetooth controller application for the KW40Z.
- Flash the file
tools/binaries/BLE_HCI_Modem.binto the KW40Z.
Now you can build and run the sample Zephyr Bluetooth host applications on the K64. You do not need to repeat this step each time you flash a new Bluetooth host application to the K64.
Navigate to the Zephyr samples/bluetooth/peripheral_hr sample application, then build and flash it to the Hexiwear K64. Make sure the OpenSDA switches on the docking station are configured for the K64.
Reset the KW40Z and the K64 using the push buttons on the docking station.
Install the Kinetis BLE Toolbox on your smartphone:
Open the app, tap the Heart Rate feature, and you should see a Zephyr Heartrate Sensor device. Tap the Zephyr Heartrate Sensor device and you will then see a plot of the heart rate data that updates once per second.
The KW40Z is a secondary SoC on the board that provides wireless connectivity with a multimode BLE and 802.15.4 radio.
For more information about the KW40Z SoC:
The hexiwear/mkw40z4 board variant supports the following hardware features:
| Interface | Controller | Driver/Component |
|---|---|---|
| NVIC | on-chip | nested vector interrupt controller |
| SYSTICK | on-chip | systick |
| PINMUX | on-chip | pinmux |
| GPIO | on-chip | gpio |
| ADC | on-chip | adc |
| UART | on-chip | serial port-polling; serial port-interrupt |
| RTT | on-chip | console |
| FLASH | on-chip | soc flash |
| TRNG | on-chip | entropy |
The default configuration can be found in the defconfig file:
:zephyr_file:`boards/nxp/hexiwear/hexiwear_mkw40z4_defconfig`
Other hardware features are not currently supported by the port.
The KW40Z SoC has three pairs of pinmux/gpio controllers, but only one is currently enabled (PORTC/GPIOC) for the hexiwear/mkw40z4 board.
| Name | Function | Usage |
|---|---|---|
| PTB1 | ADC | ADC0 channel 1 |
| PTC6 | UART0_RX | UART BT HCI |
| PTC7 | UART0_TX | UART BT HCI |
The KW40Z SoC is configured to use the 32 MHz external oscillator on the board with the on-chip FLL to generate a 40 MHz system clock.
The KW40Z SoC has one UART, which is used for BT HCI. There is no UART available for a console.
Build and flash applications as usual (see build_an_application and application_run for more details).
A debug probe is used for both flashing and debugging the board. This board is configured by default to use the opensda-daplink-onboard-debug-probe, but because Segger RTT is required for a console, you must reconfigure the board for one of the following debug probes instead.
Install the jlink-debug-host-tools and make sure they are in your search path.
Follow the instructions in opensda-jlink-onboard-debug-probe to program the OpenSDA J-Link Generic Firmware for V2.1 Bootloader. Check that switches SW1 and SW2 are off, and SW3 and SW4 are on to ensure KW40Z SWD signals are connected to the OpenSDA microcontroller.
The console is available using Segger RTT.
Connect a USB cable from your PC to CN1.
Once you have started a debug session, run telnet:
$ telnet localhost 19021
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
SEGGER J-Link V6.44 - Real time terminal output
J-Link OpenSDA 2 compiled Feb 28 2017 19:27:57 V1.0, SN=621000000
Process: JLinkGDBServerCLExeHere is an example for the hello_world application.
The Segger RTT console is only available during a debug session. Use attach to start one:
Run telnet as shown earlier, and you should see the following message in the terminal:
***** Booting Zephyr OS v1.14.0-rc1 *****
Hello World! hexiwearHere is an example for the hello_world application.
Run telnet as shown earlier, step through the application in your debugger, and you should see the following message in the terminal:
***** Booting Zephyr OS v1.14.0-rc1 *****
Hello World! hexiwear