dmod-boot

Dynamic Modules (dMOD) bootloader - A minimalistic embedded project for STM32 microcontrollers.

Building

Building for Hardware

mkdir build
cd build
cmake ..
cmake --build .

Building for Renode Simulation

To build for Renode simulation (useful for automated testing without hardware):

mkdir build
cd build
cmake -DDMBOOT_EMULATION=ON ..
cmake --build .

With emulation mode enabled, the workflow targets (install-firmware, connect, monitor-gdb) work similarly to hardware mode but use Renode instead of OpenOCD.

Why Renode? Renode provides excellent STM32F7 Discovery board emulation with complete peripheral support, accurate memory mapping, and full interrupt controller implementation. This enables proper firmware execution and log capture via monitor-gdb, making it ideal for CI testing and verification.

Building with Embedded Files

You can optionally embed binary files in ROM during the build:

cmake -DCMAKE_BUILD_TYPE=Debug \
      -DTARGET=STM32F746xG \
      -DSTARTUP_DMP_FILE=path/to/startup.dmp \
      -DUSER_DATA_FILE=path/to/user_data.dat \
      -S . -B build
cmake --build build

Build Parameters:

• STARTUP_DMP_FILE (optional) - Path to a startup package file (.dmp) that will be automatically loaded using Dmod_AddPackageBuffer at boot
• USER_DATA_FILE (optional) - Path to a user data file that will be embedded in ROM, with its address and size available via environment variables USER_DATA_ADDR and USER_DATA_SIZE
• DMBOOT_EMULATION (optional) - Enable Renode simulation mode instead of hardware mode

Automatic Build-Time Embedding:

• modules.dmp - Automatically created and embedded during build if modules are specified in modules/modules.dmd. This file is loaded before startup.dmp at boot time. If no modules are defined, the file won't exist, which is not an error.

All parameters are optional. If not specified, the build will proceed with default settings.

CMake Targets

The following targets work in both hardware mode (with OpenOCD) and Renode simulation mode. The workflow is identical regardless of the mode.

install-firmware

Install firmware on the target.

• Hardware mode: Flashes firmware to the microcontroller via OpenOCD
• Renode mode: Copies firmware to a known location for Renode to use

cmake --build . --target install-firmware

connect

Connect to the target and start the debug server.

• Hardware mode: Starts OpenOCD server that allows debugging and monitoring
• Renode mode: Starts Renode with GDB server on port 3333

cmake --build . --target connect

Keep this running in one terminal while using other debugging/monitoring tools.

monitor

Monitor logs from the firmware in real-time via OpenOCD. This target:

• Automatically builds the dmlog_monitor tool for the host architecture
• Extracts the ring buffer address from the firmware's map file
• Runs dmlog_monitor with the correct configuration

Usage:

In one terminal, start OpenOCD:

cmake --build . --target connect

In another terminal, start the monitor:

cmake --build . --target monitor

The monitor will display logs from the firmware in real-time. Press Ctrl+C to exit.

monitor-gdb

Monitor logs from the firmware in real-time via GDB server. This target:

• Automatically builds the dmlog_monitor tool for the host architecture
• Extracts the ring buffer address from the firmware's map file
• Runs dmlog_monitor with GDB backend configuration

This target works identically in both hardware and Renode modes, as it connects via the GDB protocol.

Usage:

In one terminal, start the debug server:

cmake --build . --target connect

In another terminal, start the monitor using GDB mode:

cmake --build . --target monitor-gdb

The monitor will connect to the GDB server at localhost:3333. Press Ctrl+C to exit.

Note: Both OpenOCD and Renode provide a GDB server on port 3333. The monitor-gdb target connects to this GDB server interface using the GDB Remote Serial Protocol, which is an alternative to using OpenOCD's telnet interface (port 4444) used by the monitor target. Both methods work equally well for monitoring logs.

debug

Start GDB and connect to OpenOCD for debugging.

cmake --build . --target debug