I made a USB C mod for my calculator. I wired all the Vbus, ground, D+, and D- pins to the corresponding mini B traces. Also did the 5.1K resistor as a pd from CC to ground so that USB C to C would work as well. The calculator works with USB A to C and USB C to C but when I use a USB C to C 100W cable it does not work. Any ideas why?
First image is just the mod itself, second image is with a standard USB C to C cable, third image is with an Anker 100W USB C to C cable
Here is the more info about the basic usb c connector breakout board I bought if needed:
https://www.aliexpress.com/item/4001035781660.html
Best Answer
You are only showing one resistor on your USB C receptacle board.
For a proper USB C receptacle configuration, you need a resistor per CC pin.
Inside an USB C able with a configuration chip, one of the CC lines gets connected between both devices, and the cable presents a low value resistor on both sides on the other CC pin.
Because your USB C breakout board has both USB CC lines connected to each other, the detection signal is coming into the breakout board via 1 CC pin, and then going out though the other, instead of properly seeing the 5.1k identification resistor.
It works with 60W 2.0 USB C to C cables, since they do not have a chip inside the cable, so the short on your board does not interfere with the operation
Make sure to wire it up so that you have an distinct 5.1k resistor for each CC of the receptacle, instead of trying to save on 1 part and combining the CC pins of the receptacle.
For reference, this is how termination is shown in the USB C specification: (Rd = 5.1k 20%, Ra = the resistor inside your active cable)