Renode

Renode is an emulator targeting microcontroller-class devices. This port is a minimal version of CircuitPython that runs under Renode. Renode is designed to mimic full microcontrollers but CP uses more peripherals than what Renode has implemented so far. This port allows us to run on a variety of CPUs without worrying about peripherals.

Running

  1. Get Renode: https://renode.io/#downloads

  2. cd ports/renode

  3. make BOARD=renode_cortex_m0plus

  4. In another tab: tio /tmp/cp-uart

  5. renode

  6. In renode: include @renode.resc

  8. start

  9. pause

  10. quit

Step 4 sets up tio to talk to CircuitPython via UART <-> PTY bridge.

Other stuff

Emulator logging

Renode modules have debug logging that can be enabled with logLevel with an int between -1 for NOISY and 3 for errors only.

GDB

Renode can provide a GDB server. It is very useful for precisely controlling the emulator’s execution.

machine StartGdbServer 3333 true

Execution profiling

In renode do cpu EnableProfiler CollapsedStack $ORIGIN/profile.folded before starting the emulation. You can view it using Speedscope. CircuitPython calls a lot of functions and may overwhelm speedscope. You can enable this tracing over a specific section of CircuitPython execution to limit the capture size.

Related Renode Docs

Execution tracing

If you want to see every instruction run you can do: cpu CreateExecutionTracing "tracer_name" $ORIGIN/instruction_trace.txt Disassembly.