Consider providing a step by step guide to running an Arduino sketch using simavr

[TomasHubelbauer]

Hi there, this project looks like exactly what I need from my searching around, but I am not capable of figuring out how to actually use it for my usecase. I have an Arduino sketch which computes some stuff (based on data included in its contents) and writes the results to the serial. I would like to run this sketch using simavr and see the results written to serial in my terminal. I read the readme, the manual (way over my head) and searched through GitHub issues containing arduino, which led me to #270 where I saw @idoc had the same usecase, so I also asked them for the same in that (closed) issue. If they reply, I will PR the project README with the guide after I verify I was able to use it.

[lcgamboa]

1- Use the Arduino or avr-gcc to compile the sketch to generate the .hex file.
2- Use the patched version of simduino of my fork https://github.com/lcgamboa/simavr/ with option SIMAVR_UART_XTERM=1 and the .hex file.

Obs: avrdude is for transfer the .hex file over serial to arduino bootloader, this is not necessary in your usecase.

You can try my graphic arduino simulator https://github.com/lcgamboa/picsimlab as a "virtual arduino uno" with the Arduino IDE.

[TomasHubelbauer]

I tried to use the Arduino CLI to compile the sketch (I don't like the Arduino IDE very much so I try to see if I can do this part using CLI tools only) and it spit out a HEX file and an ELF file, so step one is covered.

For step 2, I found that when using an HEX, the m and f flags are both mandatory, for ELF only the m one is. (m is mcu and f is freq)

When I tried an ELF I got Unable to load firmware.

When I tried a HEX I got Unable to load IHEX file.

Looks like simavr doesn't like HEX/ELF files produced by Arduino CLI. Also the Homebrew installation method seems to not install run_avr and I am not sure if in order to real serial output I need that or simavr suffices. Also I was unable to find any documentation about how the environment variables for terminal output work, even though you mentioned one and another one was mentioned in some open issue.

I tried PicSimLab on macOS using Wine and it looks really great! I ran into an issue tho so I opened it in your repo. I didn't try to use it as a target board with an Arduino IDE yet (like I said above for now I only have Arduino CLI).

[TomasHubelbauer]

Closed by mistake. Reopening. I didn't find other issues dealing with either of the two errors, so I'm not sure how to proceed to try and fix either of them.

I did find https://stackoverflow.com/a/7874424/2715716 tho which looks like it could be easy to use to observe the serial. Will try later.

[TomasHubelbauer]

I was able to put together instructions for compiling SimAVR on clean Ubuntu and using Arduino CLI to compile a sketch to an ELF for running in SimAVR:

curl -L https://github.com/arduino/arduino-cli/releases/download/0.5.0/arduino-cli_0.5.0_Linux_64bit.tar.gz -o arduino-cli.tar.gz
tar -xvzf arduino-cli.tar.gz
./arduino-cli core update-index
./arduino-cli core install arduino:avr
./arduino-cli compile -b arduino:avr:uno nmea-checksum.ino
apt update
apt install -y build-essential libelf-dev avr-libc gcc-avr freeglut3-dev libncurses5-dev pkg-config
git clone https://github.com/buserror/simavr.git
cd simavr
make
cd simavr
./run_avr -m atmega168 -f 16000000 ../../nmea-checksum.ino.arduino.avr.uno.elf

I'm still at loss about two things:

• How to execute the setup function of the sketch?
• How to listen to the serial port?

@lcgamboa mentions the SIMAVR_UART_XTERM environment variable, but I'm not clear on where to go from there. Should just setting it make it so that the serial messages end up in stdout of SimAVR?

[TomasHubelbauer]

My bad! With the latest version of SimAVR when running the last line in the above script, run_avr actually correctly outputted the expected serial values… I just mistook them for SimAVR's own logging… 🙄 Really dumb of me, but now that I realized that, I can say this project works perfectly! Thank you!