esp32c3

2 Articles

Run Linux By Emulating RISC-V On A RISC-V Microcontroller

April 23, 2023 by 7 Comments

For years it was a given that it was impossible to run a Linux based operating system on a less powerful computer whose architecture lacked a memory management unit. There were projects such as uCLinux which sought to provide some tidbits to low computing power Linux users, but ultimately they came to naught. It is achievable after a fashion though, by using the limited architecture to emulate a more powerful one. It’s been done on AVR chips emulating ARM, on ARM chips, and now someone’s done it on an ESP32-C3 microcontroller, a RISC-V part running a RISC-V emulator. What’s going on?

RISC-V is an architecture specification that can be implemented at many levels from a simple microcontroller or even a pile of 74 logic to a full-fat application processor. The ESP32-C3 lies towards the less complicated end of this curve, though that’s not the whole reason for the emulation. The PSRAM storage is used by the C3 as data storage and can’t be used to run software, so to access all that memory capacity an emulator is required that in turn can use the PSRAM as its program memory. It’s a necessary trick for Espressif’s implementation of the architecture.

Surprisingly it’s not as slow as might be expected, with a boot-up time under two minutes. It’s not what we’d expect from our desktop powerhouses, but it’s not so long ago that certain lower-power full-fat processors could be just as lethargic. For past glories, see the AVR running Linux, and the RP2040.

Low-Power Wi-Fi Includes E-Paper Display

March 10, 2023 by 6 Comments

Designing devices that can operate in remote environments on battery power is often challenging, especially if the devices need to last a long time between charges or battery swaps. Thankfully there are some things available that make these tasks a little easier, such as e-ink or e-paper displays which only use power when making changes to the display. That doesn’t solve all of the challenges of low-power devices, but [Albertas] shows us a few other tricks with this development board.

The platform is designed around an e-paper display and is meant to be used in places where something like sensor data needs to not only be collected, but also displayed. It also uses the ESP32C3 microcontroller as a platform which is well-known for its low power capabilities, and additionally has an on-board temperature and humidity sensor. With Bluetooth included as well, the tiny device can connect to plenty of wireless networks while consuming a remarkably low 34 µA in standby.

With a platform like this that can use extremely low power when not taking measurements, a battery charge can last a surprisingly long time. And, since it is based on common components, adding even a slightly larger battery would not be too difficult and could greatly extend this capability as well. But, we have seen similar builds running on nothing more than a coin cell, so doing so might only be necessary in the most extreme of situations.