If the polyfuse has tripped, you will get a low current. It would be much better to measure the voltage across each polyfuse. Any significant voltage will show the the polyfuse is blocking the current.Grumpy Mike wrote:I had exactly the same problem
http://www.raspberrypi.org/phpBB3/viewt ... =28&t=6592
However the current is not the issue as it only draws 22mA, I measured it.
It is the software that is wrong or the way the poly fuses mess about with the supply regulation.
Look you keep saying this like it was some sort of truth. It is not. The keyboard in not rated at 200mA it shows up in the USB probe as requiring 50mA and so does the hub. BUT when I measured it the whole thing only takes 22.9mA - the whole thing! Yes I had nothing connected into the hub just the keyboard. Are you saying the Pi knows that potentially it can take more current and so crashes early to save time?mahjongg wrote:The apple wired keyboard has a built in 2 port hub, so you can plug in two other USB devices, such as a mouse. The keyboard is rated 200mA, therefore its not a "single current unit" device (with "current unit" being the technical term for 100mA in "USB speak").
Hi Mike,Grumpy Mike wrote: What part of it is not a power issue do you not understand.
The fact that some people report it working through a powered hub suggested to me something wrong with the timing in the software that, going through a hub, fixes.
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DEBUG:handle_hc_chhltd_intr_dma:: XactErr without NYET/NAK/ACK
this is definitely a Debian Squeeze driver issue. My keyboard & mouse work fine on the RasPi on both Arch & Fedora Remix 17.
It might say 200mA on the back, but that's not what it's telling your system. It's telling your system it needs *up to* 50mA + 50mA (unless you have a model that's radically different to any of mine)
The problem isn't the keyboard. Yes, plugging stuff into its hub is a potential problem, but - y'know, "don't do that, kids." The actual and major problem is the USB (and overall) power policy taken on the Pi boards.tufty wrote:
Using a good power supply shoving out 2.1A, and Raspbian (as the default debian may have some issues), 2 Apple branded and one Apple-style keyboards work fine on my board that won't even boot "naked" off a 700mA wall wart. http://www.raspberrypi.org/phpBB3/viewt ... 799#p94619
No ... you totally misunderstand what that rating value means. I have worked for a large company with it's own compliance department and I have been responsible for putting such ratings on devices. This has involved me discussing the labeling requirements with the experts, people who have a full time job reading and interpreting the legislation.
Fight to the death?markb wrote:Hmm, mahjongg's arguement is pretty convincing, but then again so is Grumpy Mike's. There's only one way to resolve this........
Yup! The same Apple keyboard works fine when I boot up the Arch distro. So this is a USB issue with Debian.mahjongg wrote:So thom_thumb please do try another distro, and see if that solves the problem.
Again you seem to be missing the point and that point is my measurements of the voltage show that I have 4.83V across the not working correctly keyboard. So what ever class it is in there is enough voltage to operate it. So it is not a power issue!!!!!mahjongg wrote: Multiple current unit devices are not, and thus may require 4.75 Volt.
When drawing the same current, the first call may work, while the second class may fail in a situation where they receive a voltage between 4.4 and 4.75 volt.
I never claimed that the label meant it could draw 200mA,
Which sounds to me like you are.apple keyboard claims to need 200 mA
Yes I used an unfortunate way to put that mine is labeled as "200mA" I grant you that, I should have said "-my- apple keyboard is labeled as a 200mA device" but you could probably distill from all my other remarks (like "therefore its not a "single current unit" device") that I wasn't concerned by the actual current consumption of the device, only it's class.apple keyboard claims to need 200 mA
I can confirm this. I downloaded an Arch distro and the Apple Keyboard ran sweet as a nut all afternoon, just plugged directly into the Pi. I even tried it on an unpowered hub with no problems.thom_thumb wrote: Yup! The same Apple keyboard works fine when I boot up the Arch distro. So this is a USB issue with Debian.
First thing I need to know. If you copy the kernel.img from Arch to Debian image, does it still boot? Does it make the keyboard reliable?Grumpy Mike wrote:thom_thumb wrote: So it is back to the Debian crew to fix this. How do we tell them?