This is the firmware for the TNC3 version 2.1.1 hardware.

Building

Use Eclipse with CDT and the GNU MCU Eclipse plugins.

Debugging

Logging is enabled in debug builds and is output via ITM (SWO). The firmware is distributed with an openocd stlink config file that enables ITM output to a named pipe -- swv. You must create this pipe in the top level directory.

To read from this pipe, open a terminal and run:

while true; do tr -d '\01' < swv; done

If you change the MCU's core clock, you need to adjust the timing in the stlink-tnc3.cfg config file.

Installing firmware

Firmware can be installed via the on-board ST/LINK port or via USB DFU.

USB DFU

Download the STM32CubeProgrammer from STMicroelectronics.

https://www.st.com/en/development-tools/stm32cubeprog.html

This programmer will work on Linux, OS X, and Windows.

Download the ELF file from the release (or that you have built from source).

Plug the TNC into a USB port. You should see a USB serial port enumerated.

Put the TNC into DFU mode by pressing the DFU button on the side. The TNC will only enter DFU mode when plugged into a USB port.

There is no visible indication on the TNC that it is in DFU mode

You should see the serial port device go away and a new DFU device appear.

Run the STM32CubeProgrammer from the command-line.

./STM32_Programmer_CLI -c port=USB1 -d firmware-1_0_0.elf -v -g 0x8000000

When that is complete, the DFU device will disappear and the serial port device will re-appear.