I find the ESP32 much easier to develop for, you don't need to install any toolchains, just plug in and drop code into the virtual USB drive that shows up! I wish all microcontrollers were like that these days.

That sounds like a very specific bootloader that you're using

ESP-IDF is still very nice though, and being CMake based makes it easy to integrate outside code

It supports serial based uploads, which are still pretty nice with the bundled serial monitor (one key combo to build, upload, and restart) and OTA uploads

Oh sure, but it's still way better than the last time I had to deal with an STM32 and install about 5 different things, modify a "boards.txt" file (which there were 3 copies of on my system in different places and I had no idea which was the real one) and then hit the program button with one hand with a mouse in the air while carefully timing a short of a reset trace on a PCB with the other with my elbow holding down the PCB. STM32s really suck. Never had to do that with an ESP32, at least someone made a nice bootloader for it.

How do you handle SSL? I found this very cumbersome in my experiments with esp32

I never coded on Espressif, but in other SDKs (e.g., mosquitto, mbedtls) typically this is done when you open the connection at the application layer (HTTPS, MQTTS). You pass in the cert bytes either as binary or PEM text as a char[]. Use a CA root cert(s) from your OS/browser.

EDIT: grammar and typos.

It depends on whether you want to connect to random hosts or ones that you know beforehand. The latter is very easy, I just hardcode the certificate fingerprint. The former/dealing with CAs is harder, I've never done it.

The high-level client in esp-idf handles ssl out of the box and comes with a list of pre-installed root cas.

The question, of course, is: What if these CAs expire?

ESP32 is a very generic synthesized chip, not particularly ULP oriented.

On other hand, it's the most developer friendly company out there.

I've been unsuccessful getting any proper reaction from Innophase about SDK support. Their sales seem to not even understand what we are wanting from them, and keep sending us "enter these AT commands through USB-TTL"

ESP32 is also pretty much the one, and only wireless MCU you can buy on the open market, in any quantity, on a short notice. Nothing else comes with the supply chain security like this.

> ESP32 is a very generic synthesized chip, not particularly ULP oriented.

Maybe not, but setting it up to sleep most of the time and only boot once a day to fetch the calendar and update the display should sip power pretty sparingly; I expect you'd get months if not a year or more before needing to recharge the battery.

I wanted to try their Espressif ESP32 low power 802.11 part back in March but it wasn't shipping yet. Their website isn't clear but I'll poke around and see if it has been released yet.