Fenix

A bare-metal project on the STM32F756ZG Nucleo board for learning everything about MCUs from first principles, namely:

• ARM toolchain (compared to x86, newlib, different ABI)
• Linker scripts and basic ASM bootloader to setup RAM and call main()
• How the C runtime is initialized
• How to read datasheets
• How to write software drivers

Currently comes with:

• basic RTOS with context-switching between tasks inspired by FreeRTOS
• USART driver for logging
• Ethernet + ARP, ICMP support

Notes:

• Make sure you've got the ARM GCC toolchain (arm-none-eabi-) to build
• Emulate with Renode (>= v1.14.0.6117 to fix an annoying Ethernet bug)
• I'm working on macOS, so I needed the TUN/TAP kext (you can install Tunnelblick). There's also platform-specific bridging between en0 and tap0 to connect Renode to your host interface. The device names might be different for you - edit in start.sh

Build debug with make and then run Renode with sudo ./start.sh. Currently the board has a hardcoded IP address 192.168.0.254:

• ARP: arping 192.168.0.254 -- you might need to brew install arping and add Homebrew's sbin to your path. The default MAC from Renode is 00:00:00:00:00:02.
• ICMP: ping 192.168.0.254