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by marshray 3806 days ago
For the same reason you're using USB 2.0 when you could maybe get by with USB 1.1: in a few years a big majority of the mainstream embedded chips you'll use will support USB 3.1, so you'll effectively get it for free.

I say "a few years", but I seem to recall it taking 5 or more for the transition from USB 1.1.
2 comments
bsder 3805 days ago
High speed USB 2.0 support is quite rare on cheap chips. Most are still at USB 1.1 speeds.

USB 3 connectors? WAY COOL. I'm running USB 1.1 on the inner pairs and Ethernet on the USB 3 pairs for several projects.

USB 3 standard? Oh, hell, no. The signal integrity requirements are outrageous. And most embedded chips can't even transmit at the 400+Mbps necessary to saturate even USB 2.0.

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moreati 3805 days ago
> I'm running USB 1.1 on the inner pairs and Ethernet on the USB 3 pairs for several projects

That sounds like a nice trick. Could you elaborate, or is there any public information you could link to?

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bsder 3805 days ago
Nothing proprietary. Just look at a Type C pinout.

http://arstechnica.com/gadgets/2015/01/usb-3-1-and-type-c-th...

Two TX pairs/Two RX pairs. Standard USB 2.0 in the middle.

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IshKebab 3806 days ago
Embedded chips (i.e. microcontrollers) won't support USB 3 for a long time (think 10 years at least). Very very few even support USB 2 High Speed and that was released 15 years ago.
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VLM 3805 days ago
There's a division forming in embedded where "real embedded" like my dishwasher uses an 8-bit microcontroller to turn pumps and valves on and off in sequence which may never have a USB and for price reasons will never support above USB1. It has very little stored state to talk about, and the more state and sensors the less reliable and productive it'll be, so that's unlikely to change any time soon.

The other division of embedded is best described as duct taping a tablet computer permanently to a refrigerator, and those will have USB-C like next year. In the '80s we put TVs and VCRs into the same case and called it innovation... This is the '10s version.

One type of embedded is like industrial control, the other type is like product tying.

One segment is extremely price conscious because China sells the USA 10 million value engineered dishwashers per year, and using a microcontroller that costs $1 more to do something the market is completely uninterested in is a $10M loss which the market will not tolerate. The other segment is luxury gadgets for rich people where price is no object and sales never exceed the thousands, although the web pages are extremely elaborate and expensively designed.

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