slttblep VS PlatformIO

The oscillator bit is, but I don't appear to have uploaded the one with the filter which I will need to find.

https://github.com/ErroneousBosh/slttblep

The filter is just an SVF with, with a precomputed expo scale "bent over" at the top to correct for quantisation. From that the two SVF coefficients ω/Q and ω*Q are calculated every time there's a control update and of course because you can't divide on an Arduino it uses a lookup table of reciprocals. I could probably use a "wider" table of 16-bit values for better precision.

This code here will run on an Arduino and read an analogue input which sets the pitch of a bandlimited sawtooth waveform coming out one of the PWMs.

Take a look at https://github.com/ErroneousBosh/slttblep for an example of an anti-aliased sawtooth on an Arduino. Since you're using an 8-bit Arduino you can't really multiply and can't divide at all, so you have to use the titular Stupid Lookup Table Tricks to "divide" by multiplying by a reciprocal, and use a precomputed table for the function that "smooths out" the step.

I've waffled long enough. Get an Arduino of some sort, and run this on it and read through the code until it makes more sense :-)

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.

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.

PlatformIO together with avr-stub can be used to do source level debugging but there are some caveats.

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

If the HW looks like it works, you could also try alternate programming software. (e.g. TinyGo or PlatformIO)

You might have better luck with PlatformIO than the Arduino IDE; it's better at automatically choosing the serial port, though I can't say I've used it under Windows.

My other suggestion takes more work but will make your life oh so much better. Professionally I have used and highly recommend. https://platformio.org/ which is free!

Will you be doing embedded Linux? Embedded RTOS? Bare metal? Microcontrollers? SoC (say, FPGA with a hard processor core)?

You can do a lot with QEMU. https://bootlin.com/ has a lot of great, free training material.

https://bootlin.com/doc/training/embedded-linux-qemu/embedde...

is one of my favorites.

Learning to cross-compile, do embedded debugging, the process of booting an embedded system (which varies depending on the answers to the above questions), learning how to read a technical reference for the processor you’re using as well as for peripherals you’re likely to interact with - SPI, i2c, UART, maybe PCIe, are all handy skills. Learn a bit about JTAG, hardware, reading schematics, etc. Even being able solder is helpful.

There may be books (I had a great embedded Linux book when I started) but there are lots of online materials too. Check out https://platformio.org/

There are fun embedded boards and projects for microcontrollers too - micropython on an rpi pico, tinygo, eLua, etc.