USB type C

When I was designing newest board layout, around two years ago, I briefly thought about using USB C-type connector in it. Device itself doesn't use any new USB-C related features, but new connector at least would get rid of "which way up" problem of microB.

After some reading and pondering, I found few schematics showing how to wire USB C to backwards compatibility mode, but even these were somewhat complex and with some gotchas that might have needed changed if I were to run onto them. So I abandoned the idea and used plain old micro B connector instead.

Just now we're hearing that Raspberry Pi 4 boards have problems due to new C-type connector, as they have wired CC pins incorrectly which makes board to not work with some (more expensive) cables due to power negotiating failure.

Eben Upton, co-founder of Raspberry, says; "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."

That made me smile - just a bit. Note subtle blame-shifting there? No, it's not charger does identifies Pi4 incorrectly; it's Pi4 that identifies itself as audio accessory by shorting those two pins, and charger quite correctly reacts to this by not providing power to it.

Either way, I think I'll stay away from type C for a bit longer, even if the connector itself is quite nice. There's just a few too many traps there yet.