There's also https://librepcb.org/ Has anyone had time to try Horizon and/or LibrePCB and compare them to KiCad? - Source: Hacker News / 12 months ago

On the open source front, LibrePCB seems to be the only contender, never used it myself, but have heard good things and met some devs at a conference and they were nice. The level of support you get there may be a bit more personal. Otoh, if you've never designed PCBs before, it may be hard to even tell if something is a bug... Source: about 1 year ago

I would throw LibrePCB into the mix. Coming from Eagle, it was easier for me to grasp than KiCad. Source: about 1 year ago

Also LibrePCB at https://librepcb.org A bit "lighter" in size than KiCad. Source: about 2 years ago

I've been turning out some nice results from LibrePCB. It has a learning curve like anything else but its not an impossibly convoluted workflow like some of the more established FOSS programs out there. Source: over 2 years ago

For the ESP32 in read mode, we've successfully developed a project using PlatformIO that accepts the key during build time and stores it in memory. Source: 10 months ago

Check out Zephyr OS and Platform IO. Zephyr is part of the Linux foundation and has similarities to Linux with how it performs hardware abstraction (device tree). Platform IO integrates with other frameworks including mbed and Arduino. Source: 10 months ago

PlatformIO together with avr-stub can be used to do source level debugging but there are some caveats. Source: about 1 year ago

Look into https://platformio.org/, it can abstract over a few RTOSes, and can show you which OSes work with which chips/boards. Source: about 1 year ago

If the HW looks like it works, you could also try alternate programming software. (e.g. TinyGo or PlatformIO). Source: about 1 year ago