Apple Lightning (2020)
On a related tangent: I'm really puzzled by these PWM-based _digital_ signaling protocols --- more so (apparently in this case) where the period isn't even fixed. The most prominent example is probably the WS2812 RGB LED, a.k.a. NeoPixel. I can get it when a PWM line carries an analog-ish duty cycle signal, but using positive and negative _widths_ to signal bit-for-bit when you control both sides of the link doesn't make sense to me engineering-wise --- if not for speed (think USB3+), not for robustness (think something like Ethernet), and not for impl simplicity (think I2C/SPI/SDIO), then for what? Maximum pain when implemented by a third party? (/s but not really)