Yet another simulator for Microchip AVR microcontrollers, inspired from simavr

yasimavr is a simulator for AVR 8-bits microcontrollers. It is mainly aimed at the Mega0 and later XT series (ATmega80x-160x-320x-480x and others) with a possibility to work with older series. (ATMega48/88/168/328 and others)

It is composed of 2 layers:

• a C++ layer for the core API and the various peripheral simulation models

• a Python layer to handle the configuration, utilities, data recording, and external components

Installation

Thanks

Quite a few ideas in this software - and even big chunks of code - originate from simavr. (https://github.com/buserror/simavr) Big thanks to the simavr authors for this great tool !

Supported IOs

• GPIO

• SPI

• TWI

• USART

Supported Cores

The package includes a predefined set of MCU models:

• ATMegaxx8 series (ATMega48/88/168/328)

• ATTinyx4 series (ATTiny24/44/84)

• ATMega 0-series (ATMega808/809/1608/1609/3208/3209/4808/4809)

• ATTiny 0-series (ATTiny202/204/402/404/406/804/806/807/1604/1606/1607)

Other device models can be easily simulated by creating a YAML config file. A template is provided, and the example atgiga4809 shows how to load and use a customised device configuration. New simulation models for peripherals can be created in Python or C++ using the provided API.

Features

• Real-time/Fast mode : yasimavr can try to sync the simulated time with system time or run as fast as possible

• AVR-GDB integration : yasimavr can acts as a GDB backend stub, with support for breakpoints and watchpoints

• VCD export : yasimavr can export traces of pin states, GPIO ports, interrupt vectors, memory locations or generic signals in Value Change Dump (VCD) files

• MCU dump : at any point of the simulation, yasimavr can create a snapshot of the state of the MCU model, including all registers and memories and save it in a text file.

• “Zombie” mode : yasimavr can directly interact with simulated peripherals by acting as the CPU. This is useful to verify customised peripheral models or a test script.

• Probing : yasimavr can read/write CPU registers or memories on-the-fly. This is useful to force the firmware into certain branches for example, improving test coverage.

How to use

yasimavr can be used as a Python package to run a prepared simulation script. (See the examples for how it looks like)

It also supports direct command line use:

• python -m yasimavr [options] [firmware]

For the list of command line options, execute python -m yasimavr -h

Some simple script examples are available here: https://github.com/clesav/yasimavr/tree/main/examples

Documentation

The documentation is still a work in progress but will be progressively completed. The online version, including an API reference, can be read on the Read the Docs:

• [Development documentation] http://yasimavr.readthedocs.io/en/latest/

• [Stable documentation] http://yasimavr.readthedocs.io/en/stable/