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USB and FW Ports during Deep Sleep

Message #1 - Posted 2006/12/12 - pixel_a_ted

I believe that when I connect my iPod to the FW port of my G5 it continues to charge when the computer goes to sleep. I recently got a new iPod Shuffle that uses USB. I connected it to a port on the computer but when the computer went to sleep the light that indicates charging goes out.

So, I guess to conclude from this that the FW port continues to have power when the computer sleeps but not so for the USB port. I'd just like to get a confirmation on this and also, although I know it's not likely, I'm just wondering if there is a way to keep the USB port on during sleep.

Thanks.

Message #2 - Posted 2006/12/12 - larwe

pixel_a_ted wrote:

power when the computer sleeps but not so for the USB port. I'd just like to get a confirmation on this and also, although I know it's not likely, I'm just wondering if there is a way to keep the USB port on

The USB specification states that the port should not supply power unless the machine is ready to enumerate an inserted device.

(Many computer vendors violate this spec, by the way).

Message #3 - Posted 2006/12/12 - Malcolm

On 2006-12-12 10:40:00 -0500, pixel_a_ted said:

I believe that when I connect my iPod to the FW port of my G5 it continues to charge when the computer goes to sleep. I recently got a new iPod Shuffle that uses USB. I connected it to a port on the computer but when the computer went to sleep the light that indicates charging goes out.

So, I guess to conclude from this that the FW port continues to have power when the computer sleeps but not so for the USB port. I'd just like to get a confirmation on this and also, although I know it's not likely, I'm just wondering if there is a way to keep the USB port on during sleep.

Thanks.

The FireWire power should also be off during deep sleep.

Message #4 - Posted 2006/12/13 - john evans

On 2006-12-12 18:14:45 +0000, Malcolm said:

On 2006-12-12 10:40:00 -0500, pixel_a_ted said:

I believe that when I connect my iPod to the FW port of my G5 it continues to charge when the computer goes to sleep. I recently got a new iPod Shuffle that uses USB. I connected it to a port on the computer but when the computer went to sleep the light that indicates charging goes out.

So, I guess to conclude from this that the FW port continues to have power when the computer sleeps but not so for the USB port. I'd just like to get a confirmation on this and also, although I know it's not likely, I'm just wondering if there is a way to keep the USB port on during sleep.

Thanks.

The FireWire power should also be off during deep sleep.

I've just tested the FW port on my shut down intel mini & power is present.

Message #5 - Posted 2006/12/17 - zit

john evans wrote:

I've just tested the FW port on my shut down intel mini & power is present.

If my TiBook 800 is plugged in to the wall, then it provides FW power during sleep.
Providing power while shut down is brain dead.

Message #6 - Posted 2006/12/18 - Barry Twycross

Previously, larwe wrote:

The USB specification states that the port should not supply power unless the machine is ready to enumerate an inserted device.

(Many computer vendors violate this spec, by the way).

Which particular part of the spec are you thinking of? I can't think of one which says that.

When a Mac sleeps, the USB ports are put into suspend mode. Power is present at the port, but a device (such as an iPod) is not allowed to take any significant power from the port. With a little cooperation between the Mac and the iPod it would be possible for the iPod to charge while the Mac is sleeping, but its not been implimented like that.

I would expect a desktop not to charge an iPod over FireWire in sleep. Usually a desktop's power supply is in a standby mode when the Mac is sleeping, its not designed to supply signifcant amounts of power, just enough to keep the RAM alive. (But I seem to be wrong about that.)

Laptops are a bit different, they'll charge the iPod in sleep via FireWire when plugged into A/C power, but not when they're running off battery.

Barry
Barry@netbox.com <http://www.netbox.com/barry> ------
(I should put something down here).

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