Monday, March 27, 2023

Espressif IoT Development Framework

So far, I have been programming my ┬Ácontrollers using the Arduino IDE. As I progressed with my TurboLEDz experiments, I came across different ┬Ácontrollers, including the ESP32 series from Espressif.

Espressif actually has their own SDK, which targets the command line. As I feel quite at home on the command-line, I decided to switch over to the Espressif SDK, which is called ESP IDF, or ESP IoT Development Framework.

This environment is based on cmake and python tools that wrap it. Nowadays, it recommends to use it with vscode IDE, but frankly, I found it to work better without.

You mainly interface with the build environment using the tool. The typical sequence would be:

    $ set-target esp32s2
    $ build
    $ flash
    $ monitor

And what I really appreciate from ESP IDF is that you can code in pure C, without any C++ stuff involved. No need for .ino files, either. Plain, simple C. I love it.

Speaking of Internet of Things... I've always found it to be a nebulous term. But I guess it pertains to devices that don't have a screen, keyboard, mouse, but do have Ethernet/WiFi? And thanks to the march of progress, those tiny little devices are typically as capable as desktop computers were two decades ago?

My favourite ┬Ácontrollers are RISCV based. And some devices really blur the line between ┬Ácontroller and single-board-computer. Like the Pine64's Ox64 which is powerful enough to run Linux (but witout the protected memory, I think.)

I also like the ESP32 with two cores, a lot. It enabled me to create this voice-changer where the two cores can tag-team: one core is computing the Fourier Transformations while the other is doing I2S, and then they switch. So one core does everything for the odd-numbered batches with samples, and one core does everything for the even-numbered batches. Nice low-latency concurrency. Yay! But that project was all in Arduino IDE.

For my fist IDF project, I wrote a single-header-file piece of code for use with Adafruit's LED backpack. See my ledbp.h gist. It sits on top of Espressif's driver/i2c.h code.