15 August 2022 · 1451 words · 7 mins
Taking a closer look at the PWM behavior of the WS2812: Why does it have 11 bit PWM resolution when only 8 bits are used for color data?
23 January 2022 · 2310 words · 11 mins
Reverse-engineers a whole-wire LED Christmas string that encodes data on the supply rails, mapping its protocol.
27 February 2021 · 1775 words · 9 mins
What would it take to build an addressable LED like the WS2812 (aka Neopixel) using only discrete transistors? Time for a small “1960 style logic meets modern application” technology fusion project.
5 April 2020 · 1455 words · 7 mins
Builds an addressable seven-segment display module using Padauk MCUs, covering protocol details and firmware.
13 December 2016 · 1124 words · 6 mins
Analyzing the SK9822 addressable RGB-LED, a clone of the SPI based APA102.
9 March 2016 · 669 words · 4 mins
Analyzing a new addressable RGB LED: The SK6812.
30 November 2014 · 981 words · 5 mins
Dissects APA102 timing details to explain start frames, data forwarding, and reliable end-frame clocking.
27 August 2014 · 771 words · 4 mins
Investigating the SPI-based APA102/APA102C LED, outlining its SPI protocol, global brightness control, and fast PWM behavior.
19 March 2014 · 940 words · 5 mins
Implementing a stripped down version of V-USB including a WS2812 controller on a minimal ATtiny10 MCUs with only 1kb of flash.
19 January 2014 · 623 words · 3 mins
Implementation of the optimized light_ws2812 driver with hand crafted assembly inner loop that bit-bangs LEDs even at 4 MHz without timing violations on an AVR.
14 January 2014 · 1419 words · 7 mins
Analyzing and understanding the WS2812 timing, protocol tolerances, and hardware behavior to enable a reliable driver implementation.