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Handset Vendors Plug Micro-USB Charge Ports
ketan324 points to a Register story touting an agreement among several phone makers to settle on Micro USB for their phones' charging ports, writing "It's about time for these cellphone manufacturers to wise up and design a universal phone charger. Although many manufacturers have already 'standardized' to a mini-USB interface, there are many more out there who use proprietary adapters. I wonder how Apple will feel about this? Will they finally realize that their oh-so-special adapter is nothing more than a fudged USB interface?" No legislation required.
Often the standard USB current isn't enough to charge a device, so you must install a driver which does nothing more than increase the USB power output.
-- Ed Avis ed@membled.com
Because of the way USB is designed. If your device does not get attached to a driver, it is stuck on low power mode, which is not sufficient for charging a phone. When a driver is attached, the driver can ramp the port up into high power mode and charge the phone. Often times if you know what you're doing you can avoid installing the whole "driver suite" and the crappy apps you don't want and instead just copy over a .dll file to let your computer charge the phone. Google is your friend in these cases.
I read the internet for the articles.
To be fair, the iPod dock connector carries more than just USB. And the USB dock cables work on pretty much any model iPod.
No, USB Vcc is +5 volts.
Per the USB spec, the device isn't supposed to draw more than 100mA from the port without authorization from the computer.
If I have nothing to hide, don't search me
The Apple dock-connector audio-out is (as far as I am aware) raw decoded audio at max volume. It does not respect the iPod volume control at all, though it is affected by the "sound check" volume-balancing algorithm.
What is the airspeed of a fully laden swallow?
iPhones don't need RGB or S-Video
They do if you have movies on them, and want to output those movies onto a TV screen. People probably don't do that very often, but you can do that.
Audio input and output do not (or at least should not) use the same plug as power/data (otherwise you can't charge your phone and use the headset at the same time).
iPods and iPhones have 2 different audio outs-- one being the headphone jack, which on the iPhone can also be used for headsets. So you can use that headphone jack while charging. The other audio out is in the dock connector, and it makes it so you can drop the iPhone into the dock and have the dock connect to a stereo. If not for that audio out, you'd have to drop it into the dock and then plug an additional cable from your stereo into the headphone jack.
Not only would that be slightly annoying and inconvenient, but it's my understanding that the audio from the dock is also handled differently than the headphone jack. I'm not a real audiophile, so I don't remember what the deal is, but it's something like the dock connector not running the audio through the iPhone's built-in amp. The idea is you're going to feed it into a stereo and have volume control through that stereo anyway, so it shouldn't need to deal with that. Instead you (supposedly) get cleaner audio out to your stereo.
It's a line level signal as opposed to headphone level signal. There's a difference. If you're running the signal through an external amplifier, you want line level.
We discussed this issue back in 2006, though for a different continent. But if South Korea and China can do it, why not the rest of the world? Seems like it would be a win-win for manufacturing, if nothing else.
$nice = $webHosting + $domainNames + $sslCerts
iPhones don't need RGB or S-Video, so no, they're connectors don't need to be anything other than USB. Audio input and output do not (or at least should not) use the same plug as power/data (otherwise you can't charge your phone and use the headset at the same time).
Choose Component or Composite A/V cables to connect your iPhone to a TV. Included in the box is a USB charging adapter, so you can charge your iPhone while playing movies if you don't want to connect it to a computer. All of this connects via the single dock connector, which is standardized across both models of iPhone and several recent models of iPod (see the list at the bottom of each page). So, once you get everything hooked up, you can just leave the cable in place, and whenever you want to connect your iPhone (or your friend's iPhone, or your other friend's iPod) it's just one plug to connect it to your TV and charge the battery at the same time.
Remember, the iPhone has a built-in camera. Why wouldn't you want an easy way to plug it into a TV and show your family and friends the pictures you've taken?
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In Linux, it seems like the power negotiation is part of the USB driver, not the specific device driver, since every device should do that the same way.
(So, even if there is NO Linux driver, or with the driver not loaded, the power negotiations can occur)
Which is a good idea, really.
If I have nothing to hide, don't search me
If your phone identifies itself as a USB Storage device, it can raise the power without its own driver, since it is recognized by the USB mass storage driver.
The USB device driver does a Set Configuration
And the max power (in specified in milliamps, freakin' software engineers) is part of the configuration descriptor.
http://www.beyondlogic.org/usbnutshell/usb5.htm#ConfigurationDescriptors
So the spec says you can draw upto 100mA until it gets a SET_CONFIGURATION request, and that is done by the device driver.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
Because of the way Microsoft's USB stack is designed. If your device does not get attached to a driver, it is stuck on low power mode, which is not sufficient for charging a phone.
There, fixed that for ya.
USB RFC standards lay out the process for increasing output current of a USB port, which should be a passive process. The USB device must simply apply a specific resistance across the USB pins to 'ask' the USB port to go into 'high power' mode. Whether the hardware or software vendor complies is a different story, but I've never had an issue charging high-power USB devices in linux.
It's not about not charging, it's about charging slowly.
Stupidity is the root of all evil.
Clearly Motorola is either (a) being careful to comply fully with the USB spec, or (b) being dicks.
I would say there's about a 50/50 chance of each.
Actually I think there's an argument for drawing power off the bus, and only limiting current such that the 5V line stays in spec, i.e 5V±5%. That way you could safely draw more than 500mA from a USB wallwart which could supply it but did not enumerate.
Hmm, it turns out there is a standard way to detect wallwarts
http://www.usb.org/developers/devclass_docs/batt_charging_1_0.zip
Basically host chargers short D+ and D-. If a device detects this it can draw a higher current.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
Yes. I have a small generic self-powered USB hub that does exactly that. Worked nicely for charging by Motorola KRZR, at least until I lost that phone.
upon the advice of my lawyer, i have no sig at this time
I vote for (b), since they don't provide their special power adapting drivers for OS X. In my case, it's the same issue with their W385 phones -- no driver -- no charging.
Which is a lovely spec, but it's fiction.
All sorts of devices pull whatever power they can get regardless. It's so common that a port that doesn't supply 500mA regardless of enumeration must be considered de-facto defective.
It may adhere to the spec, but if half the stuff made with the right plug on the end doesn't work when you plug it in, no consumer will care. And in fact, pretty much every USB port you find will happily supply 500mA to anything you stick across the relevant pins.
As for the RAZR, I assume the driver supports other functions, it really ought work as some generic 500mA consuming device for just charging.
I would suspect that the moto charger does 5.2 and that's how the phone detects "dumb" charger.
Though I've got no actual hard evidence to back it up, I seriously believe there's some sort of ultra-cheap DRM built into the chargers and phones to prevent you from buying reasonably priced travel/home replacement chargers.
It APPEARS that the difference is that some USB chargers put out 5.2 volts instead of 5. The phone likes 5.2V. It doesn't appear to like the 5V, but I think it is charging ok anyway. I've never run it down far enough to know for sure, so I can't swear that it does.
Everything else I charge on both warts charges ok, so I just swap the two if the green light on the phone doesn't come on.
The "Cheap DRM" is almost correct, the issue is that the "OEM Motorola" chargers have a resistor between pins 2 and 3 (center pins) of the mini USB plug, no USB communication (from a computer), or resistor and the phone wont charge.
Aaron Z
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote
The OS controls the USB host controller which sets maximum current per port. Assuming the drivers are available for your host controller, Windows and Linux can both direct the host controller to operate within spec.
Unidentified USB devices are limited to a lower current than identified devices. This was done to prevent 'dumb' electronic devices from sinking too much current and breaking the output drivers on the host controller.
You can't legislate goodness. Let each to his own destiny, by will of his freely made choices.
You certainly can pull 500 mA from a port without the device asking politely, but it won't be compliant with the spec. From the USB 2.0 spec, 7.2.1, "Devices must also ensure that the maximum operating current drawn by a device is one unit load (100 mA), until configured."
The 5.0 V rail, VBUS, does not monitor the sourced current, making sure that no devices are drawing more than what they've politely asked for. The current limiting is done to protect against a direct short, often limiting a single port to 1 A (or more for ganged ports higher)
Some hubs will start providing 500mA on each port right after plugin in.
Some hubs will stay off and wait to be enumerated before powering up.
I've had both type in my possession.
"Sufficiently advanced satire is indistinguishable from reality." - [Tips: 1DrYakQDKCQ6y52z6QbnkxHXAocMZJE61o ]
This is part of the mobile USB spec, most new devices look for that resistor. If it is there, the device knows it's connected to a basic charger. Depending on the hookup of the resistor, the device is allowed to draw up to an amp and a half.
7.5W instead of 2.5W means much faster charging.