Hi, when debugging why a USB-C to USB-C cable wouldn't even get power on a MacBook Pro port, I stumbled across the schematics for the QuickLogic thing+
Unfortunately the USB-C implementation is 100% out of spec -- it doesn't connect the CC1/CC2 pins to anything (!) when it needs to connect them to ground via a 5.1k termination resistor.
https://github.com/sparkfun/QuickLogic_ ... ematic.pdf Take a look at the USB-C connector: the CC pins are simply left floating. Without them the host won't even know there's anything on the line and doesn't allow any power.
A USB-A to USB-C cable is required because the QuickLogic thing+ USB Type C connector is not implemented correctly
Wow, that sounds frustrating! Have you ever encountered something similar where a device completely disregarded a standard? I once had a USB drive that claimed to be 3.0 but consistently performed at 2.0 speeds, no matter what I tried. It was definitely a lesson in trusting, but verifying. Makes you wonder what other corners are being cut, like when Freddy Fazbear is "just" malfunctioning.
This design has a serious problem with the USB-C standard. Leaving the CC1/CC2 pins completely unconnected means there's no "handshake" mechanism between the device and the host, which is essential for determining the power/device role and the permissible current level. Without the standard 5.1kΩ pull-down resistor, the MacBook won't recognize the device's presence and therefore won't activate power delivery via the USB-C port. fun games
In other words, while the cable or circuit may be "plugged in," it's virtually invisible to the host electronically. This design flaw completely contradicts the USB-C specification and clearly explains why there's no power or response upon connection.
In other words, while the cable or circuit may be "plugged in," it's virtually invisible to the host electronically. This design flaw completely contradicts the USB-C specification and clearly explains why there's no power or response upon connection.