These instructions are macOS centric right now, but the Mbed toolchain will work on Mac, Windows, and Linux. Improvments to these instructions are welcome.

Install the arm-eabi-none toolchain

brew tap PX4/homebrew-px4
brew install PX4/homebrew-px4/gcc-arm-none-eabi-63

Optionally, install nrfjprog

brew cask install nordic-nrf-command-line-tools

Checkout all submodules git submodule update --init --recursive.

Install all the Python packages required for Mbed. Your options are:

• Install from the Pipfile. pipenv install
• Install from Mbed requirements.txt pip install -r modules/mbed-os/requirements.txt

To use the Makefiles, you must set the environment variable MBED_PINETIME_PATH to the root of the repository. If anyone has ideas on how to not need this or otherwise improve the build system, let me know.

• BMA421 Accelerometer
• [-] HRS3300 Heart Rate Sensor
• Hynitron CST816S Touch Pad
• [-] Sitronix ST7789V LCD Driver
• Macronix SPI Flash
• Vibrator
• LED backlight
• ADC Battery Voltage Sense
• Physical button

00> 0x15 Touchpad

• Only responds after a touch event.
• At 100khz, Limit of read from register 0x00 after a touch event is 190-195ish bytes. This is probably due to the chip going back to sleep.

00> 0x18 ACK Accelerometer

• BMA421 -- Not a public avalible chip, therefore no publicly availible drivers.
• Similar to BMA423
• Seems to require binary blob on startup (chip firmware?)

00> 0x44 ACK HALS3300 Heart Rate Sensor

• Datasheet is OK
• Resolution was set to 16bits 0x08
• Gain was set to 1 0x02

Flash:

• SPI flash is now working with Mbed SPIF driver
• Needed to be "reset" by letting the battery die
• 4194304 bytes

Display:

• Display needs mode 3 SPI?
• https://www.allaboutcircuits.com/technical-articles/spi-serial-peripheral-interface/
• Got it sort-of working with Mbed ports of the Adafruit GFX libraries.
• Still work to be done here

I can't get the physical button to work for the life of me. Someone please help 😂