back to article NEC ready to sample 'world's first' USB 3.0 controller chip

NEC has taken the wraps off what may be the world's first control chip for USB 3.0 - aka SuperSpeed USB. The µPD720200 implements the most recent version of the USB 3.0 specification to deliver data-transfer speeds of up to 5Gb/s - more than ten times faster than USB 2.0's peak. NEC uPD720200 USB 3.0 controller NEC's µPD720200 …

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Boffin

Voltage

So, according to the block diagram... there's 3.3v and 1.05v going in.... I wonder if they're using a charge pump to generate the 5v for the usb port, or if they ommitted it in the diagram, or if it's not actually there.

OK, I appreciate that the 5v could be wired directly to the port, but the block diagram specifically mentions the port power control interface... maybe it's to enable the requests for more power and it interfaces with external power limiting hardware.

Glad to see USB3 is getting there though.

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Backwards compatibility

You mention that USB3 is back-compatible with USB2, as I expected. However, USB2 is back-compatible with USB1. Not knowing much about the inner workings of USB - will USB1 devices work on USB3 ports?

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@Voltage

Port power control block is also marked as being external to the chip, so I'd guess at the chip controls the power without routing the power THROUGH the chip.

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Anonymous Coward

Port Voltage

IMHO, it would be pretty wasteful to put 5V through silicon simply to forward on to the physical ports, so I figure that voltage would be hardwired. But someone correct me if I'm wrong.

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Anonymous Coward

USB voltage

USB power is (almost?) always switched externally to the controller chip. Processes suitable for this high speed stuff don't make good, cheap, high current FETs. (Also, cheap manufacturers want to do the power control on the cheap, with (resettable) fuses, no current monitoring, no shutdown.

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Happy

Ha this is sweet

Nice

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(Written by Reg staff)

@Greg

USB 3.0 is backward compatible with USB 1.1 - that's, in part, what the USB 2.0 element is for.

The cabling's compatible too: USB 3.0 ports will interconnect with USB 1.1/2.0 connectors. Some, but not all, will work the other way round, but USB 3.0 device plugged into USB 2.0 port will only connect at 480Mb/s peak, not 5Gb/s.

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Thumb Up

If I remember correctly ...

I saw a diagram (possibly on here) which showed the USB3.0 socket as physically compatible with USB2.0/1.1 but with a small extension to the plug so you can plug a USB2.0 plug into a USB3.0 socket and it only meets up with USB2.0 compatible pins, but the 3.0 plug fits in further to pick up the faster data transfer pins.

So it's a full implementation of USB2.0 (including 1.1 which is part of the 2.0 spec) plus extra pins for the faster connection.

Of course it could all have changed since I last looked!

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Paris Hilton

5v, 3.3v

G E E K ! ! ! !

Paris - she know about high speed

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@Greg

All there for you in black and white on the drawing. There are separate USB3 and USB2 PHYs, with the USB2 PHY handling the High Speed / Full Speed / Low Speed (i.e. USB2, USB 1.1, USB 1) traffic.

So yes, a USB3 port will be able to interface with a piece of USB1 hardware.

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Cheers guys

Ah, so that's what HS/FS/LS was. Cheers.

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