WITHOUT A DOUBT one of the biggest flaws of the USB standard is the childishly low amounts of power that can be provided and it’s been a major bugbear of the USB protocol. USB 3.0 upped it slightly, but 900mA is hardly what we’d call generous, but it seems like Intel has finally caught on and is considering some serious changes.
According to an IDF presentation by Abdul Ismail, who’s a software architect at Intel, that we had a browse through, Intel is considering making some significant changes to USB as we know it. How much of this that will turn into actual final products isn’t known, but hopefully Intel will decide to implement just about all of it. The key thing we’d like to highlight is what Intel calls PDC or Power Deliver and Control. Now, we didn’t attend the actual presentation, so we’re most likely missing a few bits and pieces. PDC is meant to allow USB devices to have the ability to read and/or report its power status and this would then allow the two devices to decide how to interact with each other when it comes to power delivery as well as which device is in control.
As an example, let’s say you have a USB docking station connected to your notebook. If the notebook is connected to a power source, then the dock will draw its power from the notebook, but if instead the dock is connected to a power source, then the notebook should be able to draw power from it. All USB devices are intended to offer this kind of functionality to some degree, but for this to work some fundamental changes have to implemented to the USB standard. Of course, not all types devices will be able to deliver power, but any device that you need to connect to a wall socket today should be able to act as a power source in Intel’s scheme.
USB devices are going to need to be able to deliver more power, a lot more power in fact and it looks like Intel wants to implement support for up to 42V at 1.8A for a total peak power draw of 35W. However, this appears to be just a first step with the presentation mentioning “future expansion to 200-300W using new connectors”. Now that might seem a little bit excessive, but it would allow you to plug in just about anything to a USB port and it would be able to either be powered by it or charged by it. However, Intel also wants USB to be able to deliver less than 5V, something that some devices require and can’t have today.
Some of Intel’s usage scenarios includes bus powered USB 3.0 RAID enclosures for up to two hard drives, monitors and printers acting as power sources for netbooks, tablets and smartphones as well as solutions where the power draw is being equalised between two devices where both are plugged into a different power source. It all sounds so very simple, but it’s actually quite complicated to make it all work.
The USB protocol is going to have to get a lot smarter, as the devices need to be able to communicate with each other in ways that aren’t possible today. Intel has also suggested that a “zero Volt start” be used, in other words when a device is inserted in a USB port, there’s no power flowing. The problem to overcome here is how the receptacle will be able to discover that a device has been inserted if there’s no power, but we’ll leave that to Intel for now.
Another problem with making “smart” USB devices is how those devices will interact when an OS wants to control them instead of the built in logic. However, this doesn’t seem like an impossible problem to solve and it would require some kind of hand-over between the logic and the OS. There are several advantages to making the USB interface smarter than it is today, but it’s also presenting a lot of challenges. Intel sure has some interesting plans, but it’s not going to be easy to implement it all and it’s going to require an entirely new ecosystem of USB devices. Of course, it’s still meant to be backwards compatible, but older devices would have limited functionality when it comes to the power control part. Intel seems to be looking ahead to the “smart-grid home”.
Another part of the presentation that caught our eye was the fact that Intel seems interested in pushing USB as an AV interface. There are already solutions from DisplayLink that allows you to send HD video and audio over USB, but it seems like Intel wants to take things even further. One problem today is that there are so many different connectors that are all used for various purposes, but Intel is suggesting that USB can replace all other connectors and cables. In fact, Intel seems to think that USB is the be all and end all solution no matter what type of device you’re trying to connect.
The presentation claims that USB 3.0 has enough bandwidth for 500 streams of DVD quality video (6Mbps) and 100 streams of HD quality video (30Mbps) and that the only limit USB has as an interface, is available bandwidth. One problem today is that there’s no so called AV classification for USB, but it seems like Intel is interested in implementing it. It is an interesting concept, but USB still has some limitations that more traditional AV interfaces don’t suffer from, such as requiring quite a lot of processing power, at least when it comes to streaming video content.
Despite Intel’s slow uptake of USB 3.0 is seems like the company is now trying to catch up and come up with additional features for the next implementation of the USB standard. Who knows, we might end up with a USB 3.1 specification in the future that adds some of the features in the presentation. The AV features should prove to be fairly straight forward to implement and would give USB a boost in the home cinema market space. As for the power changes, well, that’s much more complex and we’re not holding our breath for a quick implementation for the near future.S|A
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