Blinky, your “Hello World!”, on a PineTime smartwatch

This tutorial shows you how to create, build, and run the Blinky application on a PineTime smartwatch.

Prerequisites

If you have not removed the flash protection yet, you should to that first. See the PineTime wiki for instructions.

Create a Project

Create a new project if you do not have an existing one. You can skip this step and proceed to Create the Targets if you already have a project created.

Run the following commands to create a new project:

$ mkdir ~/dev
$ cd ~/dev
$ newt new blinky-pinetime
Downloading project skeleton from apache/mynewt-blinky...
Downloading repository mynewt-blinky
Installing skeleton in blinky-pinetime...
Project blinky-pinetime successfully created.
$ cd blinky-pinetime
$ newt upgrade
newt upgrade
Downloading repository mynewt-core (commit: master)
Downloading repository mynewt-nimble (commit: master)
Downloading repository mcuboot (commit: master)
Making the following changes to the project:
    install apache-mynewt-core (1.7.0)
    install apache-mynewt-nimble (1.2.0)
    install mcuboot (1.3.1)
$

Create the Targets

Create two targets for the PineTime - one for the bootloader and one for the Blinky application.

Run the following newt target commands, from your project directory, to create a bootloader target. We name the target boot-pinetime:

$ newt target create boot-pinetime
$ newt target set boot-pinetime app=@mcuboot/boot/mynewt
$ newt target set boot-pinetime bsp=@apache-mynewt-core/hw/bsp/pinetime
$ newt target set boot-pinetime build_profile=optimized

Run the following newt target commands to create a target for the Blinky application. We name the target blinky-pinetime.

$ newt target create blinky-pinetime
$ newt target set blinky-pinetime app=apps/blinky
$ newt target set blinky-pinetime bsp=@apache-mynewt-core/hw/bsp/pinetime
$ newt target set blinky-pinetime build_profile=debug

You can run the newt target show command to verify the target settings:

$ newt target show
targets/blinky-pinetime
    app=apps/blinky
    bsp=@apache-mynewt-core/hw/bsp/pinetime
    build_profile=debug
targets/boot-pinetime
    app=@mcuboot/boot/mynewt
    bsp=@apache-mynewt-core/hw/bsp/pinetime
    build_profile=optimized

Build the Target Executables

Run the newt build boot-pinetime command to build the bootloader:

$ newt build boot-pinetime
Building target targets/boot-pinetime
Compiling bin/targets/boot-pinetime/generated/src/boot-pinetime-sysflash.c
Compiling bin/targets/boot-pinetime/generated/src/boot-pinetime-sysinit-app.c
Compiling bin/targets/boot-pinetime/generated/src/boot-pinetime-sysdown-app.c
Compiling repos/mcuboot/boot/bootutil/src/boot_record.c
Compiling repos/mcuboot/boot/bootutil/src/caps.c

    ...

Archiving sys_sysinit.a
Archiving util_mem.a
Archiving util_rwlock.a
Linking /tmp/blinky-pinetime/bin/targets/boot-pinetime/app/boot/mynewt/mynewt.elf
Target successfully built: targets/boot-pinetime

Run the newt build blinky-pinetime command to build the Blinky application:

$ newt build blinky-pinetime
Building target targets/blinky-pinetime
Compiling bin/targets/blinky-pinetime/generated/src/blinky-pinetime-sysinit-app.c
Compiling bin/targets/blinky-pinetime/generated/src/blinky-pinetime-sysdown-app.c
Compiling bin/targets/blinky-pinetime/generated/src/blinky-pinetime-sysflash.c
Compiling repos/apache-mynewt-core/hw/bsp/pinetime/src/sbrk.c
Compiling apps/blinky/src/main.c
Assembling repos/apache-mynewt-core/hw/bsp/pinetime/src/arch/cortex_m4/gcc_startup_nrf52.s
Compiling repos/apache-mynewt-core/hw/bsp/pinetime/src/hal_bsp.c

    ...

Archiving sys_sysinit.a
Archiving util_mem.a
Archiving util_rwlock.a
Linking /tmp/blinky-pinetime/bin/targets/blinky-pinetime/app/apps/blinky/blinky.elf
Target successfully built: targets/blinky-pinetime

Sign and Create the Blinky Application Image

Run the newt create-image blinky-pinetime 1.0.0 command to create and sign the application image. You may assign an arbitrary version (e.g. 1.0.0) to the image.

$ newt create-image blinky-pinetime 1.0.0
App image succesfully generated: ~/dev/blinky-pinetime/bin/targets/blinky-pinetime/app/apps/blinky/blinky.img

Connect to the Board

  • Connect a ST-LINK programmer via USB to your computer.

  • Connect the ST-LINK programmer to the SWD connectors of the PineTime. The easiest way it to mount the PineTime on a cradle and let the programmer cable rest on the contact pads. See PineTime wiki for the pinout.

Load the Bootloader and the Blinky Application Image

Run the newt load boot-pinetime command to load the bootloader onto the board:

$ newt load boot-pinetime
Loading bootloader
$

Run the newt load blinky-pinetime command to load the Blinky application image onto the board.

$ newt load blinky-pinetime
Loading app image into slot 1

You should see the backlight of the screen board blink!

Note: The screen itself will stay black, this could make the blinking difficult to see.