Why the Raspberry Pi 4's USB-C interface is not compatible with all Type-C data lines?

Last Update Time: 2019-07-31 10:49:42

Raspberry Pi released, the Raspberry Pi 4 Model B as the latest generation of the Raspberry Pi, in addition to the performance improvements (officially, its desktop performance is comparable to the entry-level x86 PC system), the commonly used interfaces have become richer and more practical. The Pi 4 consists of two USB 2 ports and two USB 3 ports, powered by a USB-C port, plus a Gigabit Ethernet interface and headphone jack, and two micro HDMI ports (supporting two 4K monitors).

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But recently developer Tyler found a problem with the USB-C power interface of the Raspberry Pi 4. According to the developer, the Pi 4's USB-C charging interface is not compatible with all USB Type-C lines that should be supported, which means that the user may not be able to power the Raspberry Pi 4 using the Type-C data cable at hand.

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The Raspberry Pi Foundation subsequently confirmed that the Pi 4's USB-C interface had design flaws and was not compatible with all Type-C data lines.

 

According to the Pi 4 circuit diagram published by the Foundation, it uses less of a CC resistor, and the two "CC" plug-in scripts on the Pi 4 USB-C port should have their own 5.1K ohm resistors, so this design flaw eventually This allows them to share only a single resistor, undermining compatibility with many USB-C chargers.