APA102 aka “Superled”
This entry was posted in LEDs and tagged APA102, RGB LED, WS2812, WS2812B.
I contrast to the very timing-sensitive one-wire protocol of the WS2812, the APA102 uses a standard two wire SPI protocol – one clock line and one data line. Each LED has two inputs and two outputs which can be daisy chained. At the first sight this may seem wasteful, but it has the advantage of being supported by standard microcontroller periphery and it is insensitive to timing variations. Due to the critical timing requirement it is not possible to control the WS2812 from SOCs with multitasking operating systems, such as the Raspberry Pi. This should not be an issue with the APA102. Furthermore, the data can be transferred at an almost arbitrary clock rate. I was able to control the LEDs with 4 MHz SPI clock without any hitch. It appears that the maximum speed is mainly limited by the parasitics of the wiring.