Driving WS2812 LED's with STM32 DMA+Timer

The WS2812 aka the Neopixel is a very well know LED, it combines a fully self-contained PWM driver ic with RGB led’s in a cheap and (relatively) painless to work with package. The downside to these is their not-very-fun protocol that requires effort to ensure you drive it at the correct timing. Other fantastic people have already done a deep dive into this protocol. The TL;DR is that the protocol works out to encode the bit as 0 or 1 based on the pulse length, with minimum off times between bits....

July 1, 2021 · 12 min · Ben V. Brown

STM32 Hardware & Software Design Part 4

Where we left off Part 1 covered the quick rundown of selecting the STM32 and assigning a rough pinout in STMCube. Part 2 provided a quick through the schematic capture process and PCB layout at a high level. Part 3 covered exporting the PCB for manufacture and a quick run through the ordering process with PCBWay. Disclaimer In this section, I’m using PCBWay for the ordering process example. They have kindly offered to cover the cost of the production of these PCB’s before this series actually went live....

May 26, 2020 · 5 min · Ben V. Brown

STM32 Hardware & Software Design Part 3

Where we left off Part 1 covered the quick run down of selecting the STM32 and assigning a rough pinout in STMCube. Part 2 provided a quick through the schematic capture process and pcb layout at a high level. Part 3 here will cover the exporting the PCB for manufacture and a quick run through the ordering process with PCBWay. Disclaimer In this section I’m using PCBWay for the ordering process example....

April 22, 2020 · 4 min · Ben V. Brown

STM32 Hardware & Software Design Part 2

Where we left off Part 1 covered the quick run down of selecting the STM32 and assigning a rough pinout in STMCube. Part 2 here will run through the schematic capture process and pcb layout at a high level. Schematic Capture I design exclusively in KiCad now, having completely moved off other platforms over the past few years. As such this guide will only cover KiCad related design work. I highly reccomend using hierarchical sheets in your design, to allow for both (some) reuse, as well as make the seperate building blocks clearly definied....

April 11, 2020 · 8 min · Ben V. Brown

STM32 Hardware & Software Design Part 1

Outline This is a half walkthrough / half hints guide to taking a base concept for a STM32 from idea to (somewhat) working hardware. The goal is to roughly document the path I use, but not bogging down into the details on things that are easier to google. For this series, I’m looking at designing out a small development board, designed to mount to the quite nice ILI9486 LCD unit. I’m designing this mostly so that its in a nicer form factor than other development boards, and so I can use USB-C as I really dislike USB mini-B....

April 10, 2020 · 6 min · Ben V. Brown