Build & Flash

This page explains how the example projects are built and uploaded.

You need the newest C3 Compiler

To use this library you need a version of the compiler that is newer or atleast 0.8.0, since that was the point that avr support was included in the default executable.

Build an example

Use blink as the first test:

cd examples/blink
c3c build

The build uses examples/blink/project.json. The important settings are:

• dependencies: ["arduino"] — imports this library.
• dependency-search-paths: ["../../.."] — lets the example find the library from inside examples/blink.
• cpu: "atmega328p" — selects the target MCU.
• target: "elf-avr" — builds an AVR ELF file.
• use-stdlib: false and link-libc: false — keeps the binary freestanding.
• no-entry: true — uses the exported start symbol instead of a hosted entry point.

Output:

build/blink.elf

Flash with the helper script

./scripts/flash.sh

The script runs c3c build and then uploads with avrdude:

avrdude -c arduino -p atmega328p -P /dev/ttyACM0 -b 115200 \
    -U flash:w:build/blink.elf:e

Change the serial port

If your board is not on /dev/ttyACM0, edit scripts/flash.sh.

Common Linux device names:

• /dev/ttyACM0
• /dev/ttyUSB0

You can often find the device with:

ls /dev/ttyACM* /dev/ttyUSB*

Permissions

On Linux, your user may need access to the serial device. Depending on your distribution, adding the user to dialout, uucp, or a similar group may be required.

Troubleshooting

• Confirm that c3c --version reports a nightly build.
• Confirm the board is an ATmega328P-compatible Arduino Uno style board.
• Check the serial port in scripts/flash.sh.
• Make sure no serial monitor is currently using the port.