In this blog we will be concerned with the world of embedded development. I see it that the tooling and the dev environments have come a long way in the last 10 years, and it is an exciting world! This blog will be more concerned from a hobbyiest / maker viewpoint, involving parts mostly sourced from the bargain site Aliexpress.

More specifically we will be looking at IoT development. More specifically the low power wireless devices; namely BLE, Zigbee and the open standard 802.15.4. (Why they didn’t give it a human friendly name I dont know?!).

Most development walkthroughs will be done on Linux environment, specifically Debian 10/11. Linux oriented articles/guides will be scattered throughout. I’m also a Linux addict. And where possible we will take a open source/open standard approach. This tends to be relevant for longer, whereas proprietary products change or dissappear!

The primary boards/chips in our attention is the

  • Micro:Bit(nRF52833) (low power wireless)
  • Pi PICO (Cheap all rounder)
  • BL702 (wireless; abandoned for the nRF)

The BL702 is a new offering from the chip design company Bouffalo Lab, that is extremely cheap, performant RISC-V chip. With all the bells & whistles of IoT, it’s got BLE, 802.15.4, and Zigbee. See this post for further info.

The development environments we will tackle are based on open source project components integrated into the respective IDE by the vendor: such as FreeRTOS and lwIP.

FreeRTOS is a real-time kernel that enables multitasking; makes the life of a firmware dev easier. Good resources about RTOS theory include:

  • Digi-key Youtube series
  • μC/OS-II User’s Manual Chapter 2: “Real-Time Systems Concepts” pp47. Accessible here is an excellent intro into the world of RTOS. It has slow paced, thorough treatment.

PS: An abandoned write-up on the linux based RTOS - Zephyr is accessible here. It currently covers just the basics…

PS: Based off my rants about the lack of cheap hobbyiest nRF52 boards; here’s a PCB I adopted. Features a RESET button and SWD pinout; and LIPO battery charging (for those low power applications!! Why else would you want an integrated soulution?! :smiley: ). It houses the E73-2G4M08S1E modules sold in Taoboa for $2.50. It’s open licensed but with interest I could accumulate locally for posting…

pcb screenshot