Compiling the Software

Prerequisite

Make sure the Toolchain is set up as described.

Build Configurations

ZSWatch supports different board targets and logging transports. You combine them when creating a build.

Board Targets

Target	Board string	Description
WatchDK	watchdk@1/nrf5340/cpuapp	Current development kit
ZSWatch Legacy v5	zswatch_legacy@5/nrf5340/cpuapp	Legacy ZSWatch v5 hardware
ZSWatch Legacy v4	zswatch_legacy@4/nrf5340/cpuapp	Legacy ZSWatch v4 hardware
Native simulator	native_sim/native/64	Linux simulator, see Native Simulator

Debug Logging

For debug builds, you need a base config (debug.conf) plus a log transport:

Transport	Kconfig fragment	Overlay needed	Notes
UART	debug.conf, log_on_uart.conf	log_on_uart.overlay	Logs via serial
RTT	debug.conf, log_on_rtt.conf	(none)	Logs via SEGGER RTT (needs J-Link)
USB	debug.conf, log_on_usb.conf	log_on_usb.overlay	Logs via USB CDC ACM

For release builds (no logging, optimized), use release.conf instead of debug.conf.

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Option A: Build from VS Code (nRF Connect Extension)

1. Open VS Code with the nRF Connect extension.

2. In the nRF Connect sidebar, under Application, select app.

3. Click Add build configuration.

   • Target: Select your board (e.g. watchdk@1/nrf5340/cpuapp).
   • Extra Kconfig fragments: Add the config files, e.g.: debug.conf, log_on_uart.conf
   • Extra Devicetree overlays: Add if needed, e.g.: log_on_uart.overlay
   • Build Directory: Optionally name it, e.g. build_devkit.

4. Click Generate and Build.

Option B: Build from Command Line

Open an nRF Connect Terminal in VS Code (Ctrl+Shift+P → nRF Connect: Create Shell Terminal) and run:

# For example WatchDK with UART debug logging
west build --build-dir app/build_dbg_dk app \
  --board watchdk@1/nrf5340/cpuapp -- \
  -DEXTRA_CONF_FILE="boards/debug.conf;boards/log_on_uart.conf" \
  -DEXTRA_DTC_OVERLAY_FILE="boards/log_on_uart.overlay"

More build examples

# WatchDK with RTT debug (no overlay needed)
west build --build-dir app/build_dbg_dk app \
  --board watchdk@1/nrf5340/cpuapp -- \
  -DEXTRA_CONF_FILE="boards/debug.conf;boards/log_on_rtt.conf"

# Legacy ZSWatch v5 with RTT debug
west build --build-dir app/build_dbg_leg_v5 app \
  --board zswatch_legacy@5/nrf5340/cpuapp -- \
  -DEXTRA_CONF_FILE="boards/debug.conf;boards/log_on_rtt.conf"

# Native simulator (Linux)
west build --build-dir app/build app \
  --board native_sim/native/64 \
  -DSB_CONF_FILE="sysbuild_no_mcuboot_no_xip.conf"

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Flashing

From VS Code

Use the nRF Connect extension: Actions → Flash.

When hovering the Flash button, an icon to the right will appear "Erase and Flash to Board". Use it as it will be much faster.

From Command Line

west flash --build-dir app/build_dbg_dk

TODO

Document how to flash a locally built firmware image without a debugger, using MCUboot and MCUmgr tools only (USB or BLE).

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Debugging

For information on debugging, see the Debugging guide.