Understanding the APA102 “Superled”

From cpldcpu.wordpress.com 8 years ago in Blogs

A couple of weeks ago I reported about a new type of RGB-LED with integrated controller, the APA102. One of the interesting new features of this device is a two-wire SPI interface instead of the proprietary one-wire protocol of the more common WS2812. Many microcontrollers have hardware SPI functions, which...

Articles from Tim’s Blog

Does the WS2812 have integrated Gamma-Correction?

From cpldcpu.wordpress.com 7 months ago in Blogs

A while ago, I used transient current analysis to understand the behavior of the WS2812 a bit better (and to play around with my new oscilloscope). One peculiar finding was that the resolution of the pulse-width modulation engine was actually...

Analyzing a Copper String Light with unusual Phosphor Converted LEDs

From cpldcpu.wordpress.com 1 year ago in Blogs

After being amazed about finding a really clever implementation of powerline controlled LEDs in a low cost RGB “copper string light”, I bought a few other products in hope to find more LEDs with integrated ICs. At less than $4.00...

Controlling RGB LEDs with only the Powerlines: Anatomy of a Christmas Light String

From cpldcpu.wordpress.com 1 year ago in Blogs

As should be obvious from this blog, I am somewhat drawn to clever and minimalistic implementations of consumer electronics. Sometimes quite a bit of ingeniosity is going into making something “cheap”. The festive season is a boon to that, as...

The TransistorPixel

From cpldcpu.wordpress.com 2 years ago in Blogs

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. The Objective What exactly do we want to build?...

Ultra Low Power LED Flasher using the Padauk PFS154

From cpldcpu.wordpress.com 2 years ago in Blogs

Flashing a LED is certainly among the first set of problems any burgeoning electronics specialist is tackling, may it be by using an ancient NE555 or, more recently, a microcontroller to control the LED. As it turns out, we can...

Power Analysis: Probing WS2812 RGB LEDs

From cpldcpu.wordpress.com 2 years ago in Blogs

Power analysis is a technique to probe the inner workings of an integrated circuit by measuring changes in the supply current. Whenever a logic gate switches, it will cause a tiny current spike that can be measured externally. By inspecting...

Building a Chaotic Oscillator from Common Components

From cpldcpu.wordpress.com 3 years ago in Blogs

Sometimes you find things you have not even been looking for… A chaotic oscillator is an electronic circuit that can exhibit “chaotic“, nonperiodic behavior. A commonly cited example is Chua’s circuit, but there are many others. I always regarded these...

Intelligent 7-Segment Display

From cpldcpu.wordpress.com 3 years ago in Blogs

Time for another project with a super-low-cost microcontroller. But what to design? Ever since seeing a project where a $0.03 MCU controls $40 worth of intelligent RGB LEDs, I have been wondering whether this is the right place to use...

What made the 1960s CDC6600 supercomputer fast?

From cpldcpu.wordpress.com 3 years ago in Blogs

Anybody who has ever taken an advanced computer architecture class has heard of the CDC6600, which was the world’s fastest computer from 1964 to 1969. It was the machine that put Seymour Cray on the map as a supercomputer architect....

A LED-Candle based on the 3 cent MCU

From cpldcpu.wordpress.com 3 years ago in Blogs

After having reviewed sub $0.10 microcontrollers recently, it’s time for some projects using the Padauk PFS154 and PMS150C. Considering my previous investigation of electronic and non-electronic candles, it appears only natural to chose this as a target for the lowest...