you are viewing a single comment's thread
view the rest of the comments
[–] 1 point 1 year ago (2 children)

That's if the manufacturer doesn't just install a max wattage chip in every cable.

Unfortunately this is not uncommon.

  • source
  • parent
  • hideshow 2 child comments
  • [–] 1 point 1 year ago* (1 child)

    I'm not extremely familiar with the USB-C handshake, but isn't it between the device and power supply?

  • source
  • parent
  • hideshow 1 child comment
  • [–] 1 point 1 year ago

    It used to be that simple. You could put a certain value of resistor between two pins and that was that.

    This guy covered it quite well

    https://superuser.com/questions/1555520/what-can-a-program-find-out-about-a-usb-c-cable-attached-to-the-computer

    In brief, Type-C cable specs are nearly independent from USB data and USB Power Delivery (Type-C can support anything).

    By specs, Type-C connector/cable provides two methods of self-identification.

    First one is by combination of resistor pulls-up and pulls-down on both sides of CC wires. Since there are two CC pins in Type-C connectors, and several analog levels, many combinations are available. Other than connect function itself and basic determination of source-sink roles and power capacity, several "alternate" functions are defined, as Display Port, Audio, and Debug mode.

    The second amendment to Type-C is the mandatory embedding of e-markers into every C-C cable. >The information in e-marker contains name of manufacturer and current carrying capability of particular cable.

    The state of CC1/CC2 pins is usually acquired by a special CC-controller chip. The CC-controller communicates with main system by I2C interface. The register-based interface is standardized in Intel document USB Type-C Connector System Software Interface Specification

    So, many manufacturers are including markers with maximum settings that exceed the wires'/cables' capability.

  • source
  • parent