Malfunction of USB-ports
in [Asus]
|
Prev: LAN Driver for P4P800-VM
Next: P4S8X beeps Hi-Lo-Hi-Lo
From: Paul on 29 Nov 2008 11:13 Klaus Haber wrote: > Hello Paul, > > I found some time to continue the discussion. > > Am Fri, 28 Nov 2008 10:27:32 -0500 schrieb Paul: > >> Klaus Haber wrote: >>> Hello, >>> >>> I use the ASUS-Board P5GD2 Deluxe. This board has totaly 8 USB 2.0-ports, 4 >>> at the real panel direct connected and 4 ports at the front, connected by >>> cable to the board. >>> >>> I found out, that 2 ports at the front will not work properly, if I connect >>> them to my Epson Scanner. If I do so, I get a failure message, that an >>> other scanner is already connected to the computer, which is not true. All >>> other 6 USB-ports are working well with the scanner. I changed the >>> USB-cable, no success. If I connect a camera, an USB-stick, an external >>> USB-harddisk to these both ports, they all work well, exception is the >>> scanner. I have no idea, what could be reason of this effect. Have the >>> different USB-ports also differnt valances? >>> If I connect the scanner to the different ports of my laptop, also no >>> problems. So I assume, that the failure should be at the ASUS-board. >>> >>> Is there one possibility to test generally an USB-port for its >>> functionallity? >>> >>> Thank you for comments, regards >>> >>> Klaus Haber >>> >> You have one of these in the motherboard box. >> >> http://estore.asus.com/images/14-000012222.JPG > > Correct, I have this adapter (missing the game plug). >> Disconnect the front panel USB wiring. Connect up the >> 2x5 USB cable of the 14-000012222 adapter. (You don't >> need to connect the game port.) >> >> Plug the scanner into the faceplate of the adapter. >> Test the scanner. If it works with the Asus adapter, >> but not with the computer wiring, then the computer >> wiring is faulty. >> > Maybe I didn't report exactly enough. > > This adapter was installed due to the handbook of the motherboard since I > got the computer. I used this adapter all the time with success for all > commen hardware. Only the scanner was connected from the beginning to the > rear USB-port. The reason was the local arrangement of the scanner at the > table. > > Some month ago I rearranged the local hardware and the scanner moved to a > place, from which it was easier to plug the USB-cable into the adapter at > the frontside than to the real. And since this rearrangement I got the > malfunction of the scanner. Therefor I don't believe, that the malfunction > is due to a failure in wiring or thomething else. If I connect the scanner > back to the realport, it is running well again. If I connect other > consumers (cameras, sticks, harddisks a.s.o.) to the same frontadapter, > they are also running well. That would demonstrate, that the wiring is ok. > > An other point. As far as I know, there are two classes of USB-ports. I > don't mean the 1.x resp. 2.0 clas but the class of powersupply. One class > has a powercapacity of ~ 200 mA ( I don't know the exact value) and the > other class of ~ 500 mA (not the exact value). The first class is used by > hardware with low powerconsumption, the second one for high > powerconsumption. USB-hardware with high power will not run proper, if they > are connected to the lowpower USB-port. I took a look at ASUS Homepage, but > I did not found any information about the class of my ports at the > motherboard. My scanner has an own powersupply, so it should not be > necessary to use a lowpower-port. > > At the other hand, the scanner will run at all 3 USB-ports at the laptop. > > Grrrrrrrrrrrrrrrr, I don't understand this ;-) > > @Rob > > I studied your link exactly and I found nothing which did not meet my > wiring. From this point of view, every thing is wired right. > > Can you (both) give some comments to the powersupply-classes of the > USB-ports in connection with the plugged consumers? > > Regards > > Klaus > As far as I know, the classes are 100mA and 500mA. All Asus motherboard ports will be 500mA. There is a Polyfuse near each USB header, and it is rated for more than 1 amp. The 1 amp is shared by the two USB ports. So DC power should not be an issue. Each Asus port should meet the high power spec. The 100mA limit happens, when you use a bus powered hub connected to a motherboard port. Like this. 500mA ----- 100mA Motherboard_USB ------- bus_powered_hub ----- 100mA ----- 100mA ----- 100mA The current limit still applies, even if the bus powered hub has only one output port. An example of a one port hub, is a 5 meter USB active buffer cable. 500mA Motherboard_USB ------- 5_meter_buffer_cable (one port hub) ----- 100mA Bus_powered means all power is derived from the original 500mA limit. If the scanner works with the adapter I described (this one) - http://estore.asus.com/images/14-000012222.JPG but not with the computer case wiring, then the computer case wiring is not working correctly. As a front panel substitute, you can use a 5 1/4" drive bay USB panel as a substitute. For cabling, what you want is a minimum of loose wire. If the loose wires here were part of the USB cable, the electrical performance might not be very good. USB2 is a 400Mbit/sec signal, and the signal should be maintained in a transmission line environment. Single loose wires, with no ground reference, don't have a precisely defined impedance, and signal reflections result. http://c1.neweggimages.com/NeweggImage/productimage/13-999-356-02.jpg To give an example of the problem, I have an Antec case here, where the front USB port only runs at USB 1.1 speeds. This is a known problem with the cable and PCB assembly that Antec shipped with a number of their older computer cases. Antec has improved the design, with their latest stuff. I haven't heard of problems with the more recent cases. Paul
From: Klaus Haber on 30 Nov 2008 08:54 Hello Paul, Am Sat, 29 Nov 2008 11:13:33 -0500 schrieb Paul: > Klaus Haber wrote: >> Hello Paul, >> >> I found some time to continue the discussion. >> [...] >> > > As far as I know, the classes are 100mA and 500mA. All Asus motherboard > ports will be 500mA. There is a Polyfuse near each USB header, and it > is rated for more than 1 amp. The 1 amp is shared by the two USB ports. > So DC power should not be an issue. Each Asus port should meet the > high power spec. ok. > The 100mA limit happens, when you use a bus powered hub connected to a > motherboard port. Like this. > > 500mA ----- 100mA > Motherboard_USB ------- bus_powered_hub ----- 100mA > ----- 100mA > ----- 100mA > > The current limit still applies, even if the bus powered hub has only one > output port. An example of a one port hub, is a 5 meter USB active buffer cable. > > 500mA > Motherboard_USB ------- 5_meter_buffer_cable (one port hub) ----- 100mA > > Bus_powered means all power is derived from the original 500mA > limit. > > If the scanner works with the adapter I described (this one) - > > http://estore.asus.com/images/14-000012222.JPG > > but not with the computer case wiring, then the computer > case wiring is not working correctly. As a front panel > substitute, you can use a 5 1/4" drive bay USB panel > as a substitute. For cabling, what you want is a minimum > of loose wire. If the loose wires here were part of the > USB cable, the electrical performance might not be > very good. USB2 is a 400Mbit/sec signal, and the signal > should be maintained in a transmission line environment. > Single loose wires, with no ground reference, don't have > a precisely defined impedance, and signal reflections > result. > In my eyes it is very clear now, where to find the failure. I have in total 2 panels which each 2 USB-ports: One frontpanel with 2 ports and one realpanel with 2 ports. Both motherboard headers are connected by cable to these 2 panels. The frontpanel ist the malfunction equipment, the realpanel ist working well. And now I changed the cables so, that the frontpanel was fit into the header of the realpanel and the realpanel was fit into the header of the frontpanel. Result: The frontpanel USB ist working well now and the realpanel USB has malfunction. That means, that the cables of the 2 panels are ok, but one USB-header at the motherbord is not working well - let's say not working well for the scanner. Because I see no change to "repair" the motherboard, I leave this configuration. It ist now locally easier to fit the scanner cable into the front USB port. For the other equipment, which is always fixed connected by USB cables, the real ports are good, because they don't indicate any failure. Very interesting for me! Thanks again for your help, regards Klaus -- Homepage: http://www.bingo-ev.de/~Klaus.Haber "pH-Messung - einfach zu verstehen" neu: "Eine Hundegeschichte" http://www.bingo-ev.de/~Klaus.Haber/akita.html
From: Paul on 30 Nov 2008 17:20
Klaus Haber wrote: > > In my eyes it is very clear now, where to find the failure. I have in total > 2 panels which each 2 USB-ports: One frontpanel with 2 ports and one > realpanel with 2 ports. Both motherboard headers are connected by cable to > these 2 panels. The frontpanel ist the malfunction equipment, the realpanel > ist working well. And now I changed the cables so, that the frontpanel was > fit into the header of the realpanel and the realpanel was fit into the > header of the frontpanel. > Result: The frontpanel USB ist working well now and the realpanel USB has > malfunction. That means, that the cables of the 2 panels are ok, but one > USB-header at the motherbord is not working well - let's say not working > well for the scanner. Because I see no change to "repair" the motherboard, > I leave this configuration. It ist now locally easier to fit the scanner > cable into the front USB port. For the other equipment, which is always > fixed connected by USB cables, the real ports are good, because they don't > indicate any failure. > > Very interesting for me! > > Thanks again for your help, > > regards > > Klaus > That is why they give you so many USB ports. In case some of them break :-) Paul |