Low level USB port power control

This may be a software question, but is there a way to keep the USB ports from powering down on a MacBook? The power-saving feature is causing some trouble for some older USB equipment we have (like things aren't waking back up ). You can do this in Windows through the device manager, but if there is a way in OSX I would guess it's a plist modification of some kind. Thanks!

Hi Bob,
The article below should povie helpful information about power usage and connection of high-powered devices. It also shows how to verify the amount of power being provided.
Apple Computers and Displays: Powering peripherals through USB
http://support.apple.com/kb/HT4049
-Jason

Similar Messages

Low-level USB control

Hi all,
I'm trying to do some very-low level USB control using Labview. Tasks are:
-Write 1 to output
-Write 0 to output
-Write clock to output.
Very simple tasks (no need to read, just write) , but i need to be able to do this with just a USB cable attached without any device. It will be used to characterize the cable.
The other end of the cable will be terminated appropriately.
If anyone could give me some information for me to start this, that would be extremely helpful.

If you want to do something like setting the pins of a RS-232 port without a device attached, this will not work.
USB works fundamentally differently to RS-232. It is a point-to-point connection. It doesn't work open ended and you don't have direct access to the signal levels at all.
Look for a cheap I/O device instead and use it for testing.
Shane.
Say hello to my little friend.
RFC 2323 FHE-Compliant

USB port power management issue on apple aluminium wired keyboard after upgrade to 10.8.5

Hi there,
Since I upgraded my imac (late 2012) from 10.8.4 to 10.8.5 today, i can't plug any usb flash drive, or my iPhone, to the USB port of the wired keyboard anymore; I have a power management message asking to plug the usb device to the imac directly!!
It was working perfectly just before the upgrade, is it a bug, any idea?

FYI...
I tried reporting the bug but so far have had no luck being able to do so.
I went to the developer center as Eric suggested and signed in with my Apple ID.
Once there I clicked on "Bug Reporting".
That took me to a Bug Reporting page with the heading "Submitting Bugs and Feedback".
On the side of that page is a little box that says "Apple Bug Reporter: Sign in with the Apple ID you used to register as an Apple Developer to submit a bug."
(This step seems somewhat ridiculous since I had to sign in with my Apple ID just to get this far. Now it wants me to sign in again.)
When I click the the "Sign in" button I get this:
An error has occurred. Please report the error to Apple Inc. by emailing the error detail to [email protected]
So, it seems the bug reporter doesn't work. This has been going on since the time of my last post here.

Anyone having issues with USB port power after upgrading to iTunes 11.1?

After upgrading to itunes 11.1, I can no longer use the USB ports on my wired keyboard to synch my iPhone 4s, ipod Nano, and Ipad 2. Previously, I could use this port to synch and charge the nano and iphone, and synch (but not charge) my iPad. Now I simply get an error when I attach any of the devices ("a usb device needs more power").
I currently use all four of the USB ports on the back of my imac (UPS power supply, aformentioned keyboard, a Lacie backup drive that has its own power supply, and a superdrive). Interestingly, when I unplug the Superdrive (which is plugged directly into the mac on a separate USB port), the USB port on the keyboard will work. Unplugging any of the other 2 devices does not allow the port on the to work.
I bought the wired keyboard to have the easily accessible UBS port to synch my nano as well as the fact I needed a number pad.

Get yourself a good self-powered 7 port USB hub to plug your extra devices into.
Belkin International, Inc F4U041v - Best Buy
PROVANTAGE: Belkin F5U237-APL-S Hi-Speed USB 2.0 7-Port Hub for Apple #TB857LL/A
NewerTech USB2HB7PRO 7 Port Hi-Speed USB 2.0 Hub... in stock at OWC
MacAlly TRIHUB7 TriHub - 7 Port Hi-Speed USB 2.0... in stock at OWC

USB port power failure?

I'm a user of Macbook Pro 13'' Early 2011, OS X Lion pre-installed. I'm having a tiny problem with my USB port located the nearest from the front. Everytime I freshly boot-up to either Mac OS X or Window with a pre-plugged optical mouse I cannot move the cursor with my USB Mouse light show there is power on under the mouse. However, after I restart the computer again it able to moves with the mouse still plugged in.
And this USB port seem to confuse keyboard driver with USB flash under my Window 7. Thus I cannot properly eject my flash when I plug everything to this port or I lose the built-in keyboard.
P.S: I already try resetting every RAM configuration and do a clean install of Mac OS X. But still not working.
Desperately NEED HELP!!!
Any suggestion, would be appreciated.

Did you try both USB ports? Apparently on a MacBook the front port is the one to use, as the back port shares its bus with the trackpad, camera, bluetooth, etc. See this web page:
http://www.wired.com/gadgetlab/2008/05/the-macbook-all/
That said, I am investigating this topic on behalf of two clients whose MacBooks appear to have intermittent USB connectivity.

Q190 USB Port Power

I have had a Q190 for about a month. In spite of the reviews/comments that I have seen on the Q180, I am greatly satisfied with this machine. I've even become accustomed to Windows 8! :-)
Here's my issue: When the machine is in Sleep Mode, the USB Ports seem to go into a reduced power state. I want to charge my Iphones. etc., but the USB Ports (which will charge it normally) will stop charging in Sleep Mode.
I know that there is SOME power to the ports during sleep mode, because I have an LED Backlit Keyboard, and THAT remains lit during sleep mode. So, presumably, the USB Ports are going into some sort of "reduced power state" on System Sleep.
I have made (what I think), are all the proper OS changes (usb controllers are set to not allow the PC to turn off the usb, (box unchecked) and the usb selective suspend mode in advanced power settings is set to disabled). I'm also using the High Performance Power Plan. I see NO option for USB Power in the BIOS.
Does anyone have any ideas on how to keep the USB Ports on Full Power during system sleep. I know this can be done on many Windows Systems, as I have colleagues who do it regularly.
TIA! :-)

hi LeonS,
Can you try to:
1. Press the Winkey+R > type devmgmt.msc
2. On the Device Manager, navigate to Human Interface Devices
3. Do a right click > properties on all HID-compliant device and USB input Device and enable Allow this device to wake the computer under the Power Management Tab.
4. Close the device manager, put the computer to sleep and try to connect a gadget that supports USB charging
Let me know your findings
Cheers
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USB ports power management settings

An All-In-One HP Printer, Scanner, Copier is connected via USB cable, directly to one of the two USB ports in the Macbook. When the Macbook is put in sleep mode, the connection between the HP and the Macbook is interruped (I presume) because in sleep mode, the power (from the computer) to the USB ports is turned OFF, instead of being kept alive, or even reduced. Upon waking up, the HP's functions are partially disabled, e.g. there is no possibility of scanning a document. Restoring all the functions requires uninstalling the HP software, when some of its components have to be trashed manually, and reinstall the software. HP technical support has been very responsive both in contents and in speed, but suggest that the problem might be caused by the power being turned OFF to the USB ports, when the Macbook goes into sleep mode. They suggest either to power OFF the AIO HP before putting the Macbook to sleep, and powering ON the AIO after the Macbook wakes up and regains complete functionality. They also suggest to change the settings of Power Management to the USB ports. I have searched the forums here, and the web in general, but have found no indication that it is possible to change or even access the settings of the power that feeds the USB ports of the Macbook. After this long introduction, for which I apologize, here come two questions. 1) Is there a way, maybe via Terminal, to change the USB power management settings, and how? 2) If there is no such way, would it be possible to work around the problem by connecting the AIO, via USB cable, to a powered USB hub (connected to the Macbook), instead of connecting it directly to the Macbook's USB port, the "rationale" being that the USB hub is always powered, and stays powered when the Macbook is put in sleeping mode. Thanks in advance.

I have solved the issue by turning OFF the printer before sleeping or turning off the computer itself.

USB port power?

I wanted to ask before I tried this and fried my iPod. Is the USB port on the AirPort Express capable of supplying enough power to charge an iPod?

Exactly, you can get USB chargers for dirt cheap. Checkout these for $2.99US and $5.50US.

Provide USB port power during Macbook Pro Sleep mode

My old Macbook used to go to sleep, with lid closed, and charge my phone via USB cable.
With my i7 2010 15" Macbook pro however, I cannot see how to configure this same feature. Basically when the lid closes, the unit goes to sleep, including the USB ports.
In order to charge my phone, I am forced to leave the computer on.
This seems like a giant step backward for a traveler like myself, one of the main reasons I made the investment in the new Macbook Pro was for the great new battery life.

I have the same problem. This was working, but it seems that after the last security update all USB ports are turned off completely, so my iPhone and iPad (both of which I leave connected to the USB ports) do not get charged. This is a big deal with my iPhone.
Is there a configuration parameter on my MBP I should check?
Thanks!

Low Level Serial Port Access

This question has gone unanswered several times on this forum in the past but I thought I would try it once more.
Is there any Java API that is in, or will work with J2ME to allow direct read and write to the serial port similar to the functionality that javax.comm provides for j2se.
This would be useful for a project where a palmos device is used to communicate with equipment used to monitor industrial processes.

Some MIDP 1.0 devices support access to the Serial
Port.
I have done it with Motorola i85, i50 (iDen) and
Motorola T720i.
I think 95cl also supports it. I'm ALSO having problems with serial port access on
my T-Mobile Moto T720i phone. I've had MUCH success
with the Nextel i85, i50, i95cl, etc phones, but the
same code isn't running on the T720i.
What do I need to do differently???
Thanks,
-Tim

High level and low level grabs

Hi, I'm looking at different acquisition options. Fast acquisition is a priority as is fast processing. I'm a little confused on high level versus low level. Is there any benefit to which one is used? Or is it 6 one way and 1/2 a dozen the other. Thanks

If you feel comfortable using the Low Level functions I would personally recommend using them instead of the High Level. Bruce's answer is correct, high level will call low level with standard options selected. If you think of ways to improve the speed of your code, you may want to use low level, my reason is because high level VIs will actually be a function call calling other functions, which introduces a minimum delay, instead, if you use low level you are directly calling the functions for acquisition so there is kind of a small time saving if you think of it as acquisition wise.
Also, the high level VIs if you check their block diagram it has more structures for error checking, session ID checking, etc., so with low level you have direct control over the acquisitio
n from your main program without introducing innecessary structures or functions.
Regards,
Nestor Sanchez
IMAQ/Motion Support
National Instruments
Nestor
National Instruments

Mac Pro 2008 USB port problems - persistent

Hello all,
I have a 2008 Mac Pro - standard config : 2.8Ghz 2Go Ram ATI 2600.
At the outset I did a clean install onto a 1To Seagate drive.
From day 1, and before adding any third party applications, the aluminium keyboard would suddenly stop working. If I changed this for my old G5 plastic keyboard, I had no problem. The aluminium keyboard would work again sometimes if I changed USB port, sometimes only after rebooting.
This problem occurred randomly, a few, or many times a day.
Apple, after going thru' a number of tests with me over the phone, finally sent me a new keyboard (after having sent 2 white plastic models). This changed nothing. I then had a problem with the white plastic keyboard and one day, with a USB drive linked to a USB port I got the error message of having disconnected the disk without having ejected it first. That told me that the problem was not with the keyboard but with the USB ports (power to them?).
I did a clean install (with erase disk 1 pass) under 10.1.5 - the problem didn't go.
I then did a clean install again 10.1.5 followed immediately by upgrade 10.5.2 and the graphics upgrade. I installed no third party apps for 2 days. I had no problems. I installed some apps. No problems for 3 days. I ran all this time on a plastic keyboard. Today I plugged in the aluminium keyboard. No problems for 8 hours and suddenly tonight everythings starts over again.
I've had to do 4 reboots in the last hour. I'm back on the plastic keyboard. But if I lose that like last time I'm pretty convinced that this is a hardware issue.
Curiously I have not seen this problem cited in any forums on the Apple boards and other Mac
sites.
Any ideas ?
I wan't this machine changed. It's my work tool and I can't afford to lose so much time…nor to get so frustrated.
Apple, Help ! Please !
PA
P.S. My first Mac was a MAC SE !!

I think there is a problem with the usb ports on the MacPro which I also think is causing some of the bluetooth problems that are being reported around. Here's why.
I have a "base" new MacPro (2xQuad 2.8, 320G drive, etc.). After getting the unit going with the standard usb keyboard and mouse I then paired my Apple wireless keyboard and mighty mouse. All worked fine. Then the problems started. I have security set that requires a log in when booting, however after restarting, or rebooting, the MacPro the wireless keyboard and mouse were no longer recognized and I was stuck at the login screen. If I then connected my original Mac usb keyboard it would not work. The ONLY way I can get the usb keyboard to work is by having it connected when I reboot/restart. Calling Apple support was...well let's just say less than useless. So I have been doing a lot of experimenting on my own. I have finally found out that if I have nothing at all connected to any of the usb ports then the MacPro will recognize my wireless keyboard and mouse (although it does take some time to recognize it). If I connect my usb devices again and reboot...back to the same situation. No connection to my bluetooth devices and my usb keyboard will not work (unless I again reboot with it already attached). Now before you say it's my other usb devices let me tell you what I have....just a Canon printer and a Western Digital USB drive that I use for Time Machine. Both of these units have been working fine for over a year and work absolutely fine when connected to my Mac Book Pro.
I believe the bluetooth device inside is connected to the usb bus internally which is why I think the usb bus is the "root" of the problem. When certain usb devices (and heck it my be almost any usb device) are attached then the usb internal hardware screws up, which kills the bluetooth connection. I believe that this problem may be borderline (not sure if its power, timing, etc.) which is why we see so many issues that are similar, but hard to pin down.
I also believe that Leopard exacerbates this problem (but not sure yet and way too long to detail now....I'm babbling enough).
Right now the only way I can get my machine to work properly is to disconnect my printer and drive, boot the machine and then reconnect them after I have logged in. That sequence seems to work.
I know that isn't any kind of an answer, but you are certainly not the only one and I think this is just another symptom of a larger Apple USB issue. I'm continuing to investigate.
Good luck all,
rd

Re: 2 two usb ports on left side of my hp pavilion g6 2230 is not working

Hi,
Is your notebook still in warranty? Warranty status check webpage
If some ports work and others do not, then it is quite likely that the issue is hardware related. Replacing the system board would be required to resolve the issue. If the issue were operating system or driver related, then no usb ports would work.
As a workaround you can use a powered external usb hub. If you use an unpowered hub then you are quite likely to kill another port. You must have used a usb device that drew more current (in µA). The same thing happens to motherboards in PCs, so don't feel lonely. You can see what I mean about the power limits of usb ports in the following image. Go into the device manager and check your usb ports power availability and power required.
Best regards,
erico
****Please click on Accept As Solution if a suggestion solves your problem. It helps others facing the same problem to find a solution easily****
2015 Microsoft MVP - Windows Experience Consumer

Dear Sir,
I read your answer. You said that if one USB port is working, others should also work. Thus this could be hardware related problem.
Fortunately I have ubuntu also installed as second operating system.
The left usb ports are working on the Ubuntu system. Thus we can conclude that hardware is perfect.
Now with above reference, can you please guide on how can the left USB ports can also funtion?
Regards,
Rajeev
erico wrote:
Hi,
Is your notebook still in warranty? Warranty status check webpage
If some ports work and others do not, then it is quite likely that the issue is hardware related. Replacing the system board would be required to resolve the issue. If the issue were operating system or driver related, then no usb ports would work.
As a workaround you can use a powered external usb hub. If you use an unpowered hub then you are quite likely to kill another port. You must have used a usb device that drew more current (in µA). The same thing happens to motherboards in PCs, so don't feel lonely. You can see what I mean about the power limits of usb ports in the following image. Go into the device manager and check your usb ports power availability and power required.
Best regards,
erico

N585 - Win 8 Autoplay does not respond - one USB Port

I have a new (one month) N585 Ideapad, Canon Powershot camera plugged into 3 USB ports launches Windows Autoplay, the fourth (2.0 on the right, front that is NOT present on the G585) no Autoplay. I haven't installed any 3rd party SW (machine came with McAffee). Some investigation shows:
- camera appears as portable device in Device Manager (although no usual 'bong' when plugged in or removed)
- no Yellow/exclamation points for the USB hubs so that's ok
- can manually launch import w/ win8 Start/Pictures/Devices but no Autoplay popup appears
- Logitech mouse and flash drive DO work in the port
I've read everything from USB port power limit issues, to shell hardware detection, resetting Autoplay defaults, and editing the registry. Also, that Lenovos have a good number of USB port issues! Does anything jump out with the N/G series of IdeaPads???
I find it curious that this particular port is NOT on the virtually identical G585 machine profile....
Thanks in advance!

It could be that the port where it does not function may not be producing sufficient power for the given HDD. It has been shown that all USB ports do not output the same power. You might test with a USB 'Y' connector or a powered hub.
Ciao.

My frequent USB port connection has new warning?

Hello,
Just recently, I've had a new warning pop up when I connect my iPod video to my old iMac G4 on one of the 3 USB ports located on the back. The warning says something about how I've connected the iPod to a low-speed USB port (1.1) and may have performance problems.
I never had this kind of message before. I haven't used the iPod video all that much and actually prefer to connect it to my MacBook Pro but there are times when a recharge on my iMac G4 is more convenient than the laptop. Plus, I purchaed the iTunes Video Games with the G4 and anytime I restore the iPod Video I have to sync it with the G4 in order to transfer the games.
Does anyone have a reason for this message? Related to an update? Do USB ports go bad over time or wear down? Is there something else wrong with my iMac or a symptom in the ports area?
uurk
iMac G4 Mac OS X (10.4.9)
iMac G4 Mac OS X (10.4.9)
iMac G4 Mac OS X (10.4.9)

i talked with a sales rep at local apple store. he thinks it may be all the new ipod updates for the latest ipods and phone and apple created a new warning message based on quality of old USB ports on old iMacs.

Low level USB port power control

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