ULP (ESP32) : a simple example

The ULP is a low-power coprocessor (Ultra Low Power) integrated into the ESP32 MCU. It’s a very small processor that can run independently from the main cores and that has access to the GPIOs, some peripheral and an I²C controller.

The ULP is also able to run when the ESP32 is is deep-sleep mode. In this mode, nearly the whole MCU is powered-off, except the RTC domain, in which the ULP is built. It is also able to wake the ESP32 up.

A possible application of the ULP is to acquire temperature while the ESP32 is in deep-sleep and to wake it up once it reaches a specified threshold.

Programming the ULP seems very interesting, but even if the documentation from Espressif is very complete, I couldn’t find a simple and easy example to learn how to use it.

Here is then in details an ultra simple exemple : the traditional blink, which blinks 2 LEDs on the WROVER-KIT V3.

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ESP32, ESP-IDF, CMake & CLion

I’ve been working with ESP8266 and ESP32 for some times now. Until now, I used the Arduino framework, mostly because it’s easy : it provides a lot of services and libraries, allowing me to go straight to the point and concentrate on my own code.

But I like to understand what lies underneath the top-layers, get closer to the metal, the transistors, the peripherals and the registers. For that, Espressif provides a well-documented SDK, and for which a lot of resources are available online.

This framework, name ESP-IDF (“Ce framework, nommé ESP-IDF (“Espressif IoT Development Framework”) provides toolchains and tools allowing the development of application for ESP32 MCU. In fact, the Arduino framework integrates this SDK to provide a higher-level API, and compatible with other platforms

When I installed the IDF, I was surprised (in a very good way) to find CMake files! CMake is an open-source tool to manager the build process of a project, especially for C++ projects. And CMake is natively supported by my favorite IDE : CLion.

So, shouldn’t it be possible to create, edit, build and run an ESP-IDF project in CLion ? That’s what we are going to see! (TL;DR : the answer is ‘YES’!).

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Un bot pour Mastodon écrit en Micropython

Il existe déjà sur Mastodon, le réseau social libre et décentralisé dont j’ai déjà parlé à plusieurs reprises, toute une série de bots plus ou moins intéressants. Certains donnent l’évolution du nombre d’utilisateurs et d’instances sur le réseau, d’autres tootent automatiquement un résumé d’articles de blogs quand ils sont publiés, ou publient régulièrement des photos coquines. Bref, il y en a pour tous les goûts.

Moi, j’ai décidé d’écrire un bot… qui ne sert à rien! Non, l’intérêt de mon bot ne se situe pas dans sa fonctionnalité, mais plutôt dans sa conception : il va s’exécuter sur un processeur embarqué.

Dans le but de rendre le travail simple et rapide, j’ai choisis de le développer en Micropython. Et pour l’exécuter, mon choix s’est porté sur la carte Lopy de Pycom, basée sur un processeur ESP32, avec WiFi intégré. Continue reading “Un bot pour Mastodon écrit en Micropython”