Raspberry Pi Admits To Faulty USB-C Design On the Pi 4

'The Raspberry Pi 4 was announced two weeks ago as a major new upgrade
to the line of cheap single-board hobbyist computers. The Pi 4
featured a faster CPU, options for up to 4GB of RAM, and a new, modern
USB-C port for power delivery. The Pi 4 was the Raspberry Pi
Foundation's first ever USB-C device, and, well, they screwed it up.
As detailed by Tyler Ward, the Raspberry Pi 4 has a non-compliant
USB-C charging port and doesn't work with as many chargers as it
should. Thanks to the open nature of Raspberry Pi (even the schematics
are online!), Ward was able to discover that Raspberry Pi just didn't
design its USB-C port correctly. Two "CC" pins on a USB-C port are
supposed to each get their own 5.1K ohms resistor, but Raspberry Pi
came up with its own circuit design that allows them to share a single
resistor. This is not a compliant design and breaks compatibility with
some of the more powerful USB-C chargers out there.

Whether your USB-C charger works with the Pi 4 has to do with whether
it uses an "e-marked" cable. E-marked cables are fully featured USB-C
cables with chips inside that negotiate power management, accessory
modes, data rates, and other communication specs. Since the Pi 4 USB-C
port is wired incorrectly, these smart cables will detect the Pi 4 as
an "Audio Adaptor Accessory" and refuse to charge them. Usually,
e-marked cables are more expensive and come with larger,
higher-powered items, like a USB-C laptop. After reports started
popping up on the Internet, Raspberry Pi cofounder Eben Upton admitted
to TechRepublic that "A smart charger with an e-marked cable will
incorrectly identify the Raspberry Pi 4 as an audio adapter accessory
and refuse to provide power." Upton went on to say, "I expect this
will be fixed in a future board revision, but for now users will need
to apply one of the suggested workarounds. It's surprising this didn't
show up in our (quite extensive) field testing program."'

-- source: https://hardware.slashdot.org/story/19/07/09/1934205

I'll stick with my RPi3 for the time being...

Cheers, Peter
-- 
Peter Reutemann
Dept. of Computer Science
University of Waikato, NZ
+64 (7) 858-5174
http://www.cms.waikato.ac.nz/~fracpete/
http://www.data-mining.co.nz/
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