MicroPython VS esp-idf

it's not an embeddable runtime like Lua

While it's true you can't have multiple MicroPython interpreters running concurrently (or at least not easily; it's not that the design makes this impossible, it's just that all in all MicroPython is fairly young and development focus has been put elsewhere), it is possible to embed MicroPython. Not completely out of the box, needs some glue code etc. See for example https://github.com/micropython/micropython/tree/master/ports....

It's obviously not directly comparable - each port will be different - but startup time is <50ms on an RP2040 (Cortex M0 @133MHz):

https://github.com/micropython/micropython/issues/8420

Yes, although MicroPython is focused on running on microcontrollers it can be useful if you want to reduce memory consumption, flash space and even startup time on servers.

The challenge is that MicroPython has many fewer standard libraries:

https://github.com/micropython/micropython/wiki/Standard-Lib...

And so many Python libraries targeting CPython won't work out-of-the box and you'll need to modify them or use alternatives that do work on the MicroPython subset.

I'll link to it because many people don't know a version of Python runs on microcontrollers:

https://micropython.org/

I'm personally working on something like this for the ESP32, but written on top of micropython [1]. A few things are written in C such as the display driver, but otherwise most things are in micropython. We chose the T-Watch 2020 V3 microphone variant as the platform [2].

Our objective is to build a modern PDA device via a mostly stand-alone watch that can be synced across devices (initially the Linux desktop). We want to achieve tasks that you might typically do on your desktop, focussed towards productivity.

We did consider a custom OS, but decided against it for a few reasons:

1. Allowing somebody else to handle basic OS stuff allows us to concentrate on what really matters, the higher level stuff on top.

2. Having multiple threads in micropython is super simple and we are able to run many active apps at the same time, rather than having to kill them off [3]. Our background apps can continuously interact with the network in the background.

3. Code written for micropython can be easily run on other Python-capable devices.

[1] https://micropython.org/

[2] https://lilygo.cc/products/t-watch-2020-v3

[3] https://tactility.one/#/application-lifecycle

tools/mpy_ld.py: https://github.com/micropython/micropython/blob/master/tools...

tools/mpy-tool.py lists opcodes: https://github.com/micropython/micropython/blob/master/tools...

Can the same be done with .pyc files; what are the advantages of MicroPython native modules?

Why does it need wasm2c?

Any chance you could explain this to somebody who is just learning about HID and has run this example: https://github.com/espressif/esp-idf/tree/master/examples/pe... ? "non-boot protocol" I'm guessing is the key here? I don't have a super deep understanding of HID or what the "boot-protocol" refers to.

The researcher-or-tinkerer who wants to play with these commands can just not upgrade to the newer ESP-IDF. Or update to a newer ESP-IDF, and revert the patch. It's open source. https://github.com/espressif/esp-idf

The target ESP-IDF version is v5.3.2

The BT stack is based on Bluedroid, so that’s open source (up to the driver I’d guess); see here https://github.com/espressif/esp-idf/tree/master/components/...

For returning to deep sleep from the wake-up stub you can take a look at how it is done in https://github.com/espressif/esp-idf/tree/master/examples/system/deep_sleep_wake_stub

You can find the examples here: https://github.com/espressif/esp-idf/tree/master/examples

I found the spi_lcd_touch example and flashed it, and it seems to run fine with either ili9341 or gc9a01 drivers selected (although both are mirrored, and one has the colours inverted compared to the other - both of which I assume are things I can fix in either driver).

If that's the case: You register a GPIO as event source and make a task waiting for it, that then just performs the I2C-transaction. Follow this example https://github.com/espressif/esp-idf/blob/master/examples/peripherals/gpio/generic_gpio/main/gpio_example_main.c