ADuM4160 PIN pin grounding
Q. I am getting “USB device not recognized” error message – what do I do? Also, since the isolator is soldered into my circuit, “reconnect peripheral” suggestion seems too difficult to follow.
I decided to write this article after receiving several e-mails from people who bought my isolator. While setups described in those e-mails were different, the problem was the same – a PC refusing to recognize the device connected through the isolator. Here I will try to explain what is happening and also share my ideas how to troubleshoot and possibly fix the problem.
When nothing is connected to USB port, the bus is held at ground level with pull down resistors on the host side. USB device, when connected, pulls one of bus lines up, often times also with a resistor connected to Vbus and data line. Host sees it, sends bus reset and tries to query the device. If device is answering, host keeps querying the device and eventually enumerates it. When device is enumerated, application takes over.
If device is not answering (like for example, when self-powered device is turned off), host will give up and post “Device not recognized” message. To get attention from the host, we need to generate bus event, i.e., disconnect the peripheral and connect it back again.
If we are dealing with typical copper-wire-connected USB host and peripheral, which end of USB cable gets disconnected and reconnected would not matter. However, when host and peripheral are talking through ADuM4160, this is not always the case. I tested about 50 different USB devices and found out that while breaking the connection on the peripheral side works every time, host side disconnect does or does not help depending on device.
It is possible to simulate device disconnect without breaking actual connection by pulling PIN pin of ADuM4160 to ground. Normally it is held at 5V by R8 pull up resistor. This resistor is located next to peripheral side USB connector and marked 1M above it. Left side of it, the one right below the “1M” mark is connected to PIN pin (12). The closest ground point is right pad of bypass capacitor, which sits above R8. An experimenter with good eyesight and steady hand can easily connect those two points with tweezers. However, if said experimenter is not feeling comfortable operating tweezers inside powered circuit, a safer arrangement is shown on the title picture.
Disconnecting peripheral, either directly or by driving PIN pin, with power applied to the isolator and host side connected, will most likely solve device detection problem. If you still having issues with the circuit, please let me know, I will try to help.
Oleg.
Dear Oleg,
Your PIN advice works great. I installed a toggle switch between ground and R8 that allows me for “re-boot” the connection in case of accidental disconnection. I use your isolator on my USB audio DACs. I strongly recommend it for this purpose as the improvement in sound quality is evident.
Many thanks fro your help.
PS: a remark; I read 3.3VDC at R8 (not 5VDC) as it is connected to VDD2…
Thank you for the catch – I’ll make corrections to the article!
hi Oleg,
the board works great with a mice in low speed mode
in fast speed mode i get only the USB device not recognized error.
I try to use an usbasp Adapter , no way, not slow or fast.
I get only USB device not recognized. đ
regards from Germany
Uwe
From what I can see, USBasp should be compatible with this isolator. Have you tried other high-speed devices, like usb flash drive, for example?
Also, tell me about your power supply – can you measure 5volts with USBasp connected?
Hi Oleg,
I have power off my Laptop, not only a reboot.
Now i works well, in fast mode and with usbasp!
A good job….
regards from Germany
Uwe
I’m glad you got it running; however, powering the isolator from a computer is wrong. It might work but it won’t isolate. You need to use separate power supply fro peripheral side.
Hi,
Have you tested your USB Isolator with external 2.5inch portal hard drives?
Thanks
I haven’t tested it with 2.5 drives. It works fine with 3.5 external drives. What is the difference?
Hi,
I made my own circuit using this device, but it works fine on some PC’s, but on other PC’s it says, “USB device not recognized”. What do you think could be the problem?
I have pins 3,4,5 connected together and then on the other side, 12,13,14 are connected together. I am also using 24R on both sides for the D+ and D- lines.
Best Regards,
Ray
I am not using 1meg pullups or any pullups, just connecting them directly.
The circuit works on one PC, but on others there is the not recognized problem.
Have you tried grounding PIN pin as in the article (to do this, you will need a pullup on it)?
Hello and Good day
My problem is this I am using a 4160 ADUM typical configuration with the proposed Analog Divic, but when you first connect a device such as a keyboard or a mouse everything works fine. The problem is when I unplug the mouse or keyboard and put a USB flash memory tells me unrecognized disposition
The same happens if other circuits attached for the first time a USB flash memory everything works fine but when I disconnect to connect a mouse or keyboard when I connect it tells me unrecognized device that could be happening
Thanks
Hello,
I have now built and tested this device, but am experiencing strange results. Do not have issues with connected devices being recognized, but no matter what (full-speed) USB device is connected, the host computer reports that “this device can perform faster” — even though the isolator is plugged into a full-speed host port. If I simply eliminate the isolator, plugging the USB device directly into the host port, all is normal. Any suggestions?
Cheers
In USB 2.0, 3 speeds are possible – low, full, and high. You are using high speed host and device, isolator supports low and full speeds only. As long as your device is working, you can ignore this message.
Follow-up… after much swap’n and test’n it is now confirmed that the USB drivers for the Musiland Monitor01-USD conflict with whatever the ADuM4160 invokes when connected to the host computer. This holds true for XP and Win7x64, regardless of what USB device is connected to the isolator. For example, an external Seagate USB HD normally performs at ~32MB/s but if connected via the isolator it then is only able to muster ~1MB/s – IF the Musiland driver is installed. Remove that driver and all works as otherwise expected. This behavior is consistent with the “device can perform faster” notices mentioned in the last post… everything works, just at USB-1 speeds đ
I will certainly contact Musiland about this, but if anyone here has further information that would be nice to have too.
Cheers
The circuit is ok, but even I set it to ful speed, a windows alert says: “it’s not a full speed peripherical” with the isolator mounted and powered with an external supply. Do you knowe how to solve this problem?
I haven’t seen this error before. Can you make a screenshot of error message and send it to me to mazurov at circuitsathome com?
Hi,
I just connected my two boards today for the first time. I’m using Windows XP with a USB 2.0 cable, testing with a USB memory stick, and have both jumpers in the lower “Fspeed” positions. When using both boards, I get a message at the lower right of my screen saying “This device can perform faster. This USB device can perform faster if you connect it to a Hi-Speed USB 2.0 port. For a list of available ports, click here.” When I plug the memory stick into the port directly, the message does not appear.
-Bryan
This message means that Windows was not able to negotiate high-speed with high-speed device, which is not surprising since ADuM4160 supports full and low speeds only. Your drive should work just fine though; that’s exactly how I check isolators prior to shipping – I connect USB drive with large zip file to a PC via an isolator and run archive integrity test.
But it’s USB 2.0 full speed full compatible?
Hallo Oleg
I can”t get my usb isolator to work, PC/W7/64.
I was recommended by a DIY group build for audio, the usb entry
pcb work’s fine solo. The aim is to isolated pc-ground.
I cant do a desent test!!
Groet Ton
Hi Here some more info.
I did the wire at the chip , the pc react,wire away return to
where it was. i powered with a wirebridge to the vin points.
The USB pcb (= usb to I2 s interface) by
firm name altmustech” from japan/china.
It works stand alone, W7 reacts direct when cables switched.
Groet Anton (61) Holland
Didi you check the isolator with some other USB device, like, for example, USB flash drive?
Hallo Oleg
I trieed with common-usb sticks, give’s no reconnicion sign from windows. i get the feel it wont come over the chip.
Groet Ton
Hello Oleg
After some more testing , i find out (a) that if i losen the usb cable to and from isolator and usb interface windows react accordingly. (b) usb interface has a DSP with a Vbus 5volt!!
As eyesided is not ok and age (61) is making this may be a bridge to far!!
Groet Ton
Hi Oleg,
Like Igo51, I get the âthis device can perform fasterâ message. Tried three different PCs running XP and same on each. It reads memory sticks OK, but I bought mine for use with a recording device (E-MU 0204) that needs usb 2 speeds to work right. At the moment, it sees the usb link as being too low in bandwidth to allow the high sample rates I want. Do you have any further solutions?
Thanks,
Hugh
The isolator does not support high speed, only full and low. I’m not aware of any high-speed capable USB isolators, sorry.
Good morning, Oleg!
Why do not you put on the slave power galvanically isolated DC-DC converter?
What do you mean – I do have DC-DC converter on the slave and it’s isolated?
I mean, isolated DC-DC powered from the host
I’m planning to have this as an option in the next version of the isolator. The issue is max.current – currently, all isolated DC-DC modules are rated at 100ma max. and I wanted to be able to provide more than that.
LTM8022 1A Isolated DCDC
Won’t work – it requires 7V Vin.
Excuse me, LT3439
At May 19, 2011 at 3:39 pm you wrote:
Iâm currently prototyping low noise linear regulator for new âmodularâ USB isolator. The new isolator will be available with switching, linear, or USB-powered isolated supply. No ETA yet.
How do you do with this project?
Still working on it.
Sorry, but the specification defines the usb power consumption for USB 2 is 500 mA. Efficiency of modern DC-DC 72-90%. Total output at 400 mA should be ?
You are talking about current consumption. There is no specification which forbids USB Host port from sourcing more than 500ma. In fact, PC ports are often capable of 700+ ma and many hubs work in ganged current limiting mode, being able to source 2A from 4 ports – if you only use one port, you can have all of it.
1) Does this thing come with a PSU?
2) If no PSU is supplied, then what is recommended?
PSU is not included, you may use any wall wart with standard center positive round connector and 9-24V output. If you don’t have any lying around, this one will work -> http://www.sparkfun.com/products/9442 .
WE tried the solutions you suggest with pulling out USB cord at either end and still are unable to get computer to recognize USB peripheral through the isolator. Tried short USB cord to computer from isolator with flash drive. Can get the light on flash drive when wiggle in USB port – is not reliable light on. Even when find a positino that lights the flash drive continuously, the computer does not recognize the drive. We have two new isoloators and they both act the same. Odd that we have to wiggle the USP plug to get light on but even so it does not recognize the flash drive.. In any case, we have other peripherals that are not recognized eigther, including a USB power detector and a MEasurement Computing A/D interface module.
Looked at your picture and do not see that your suggested shorting points accomplish grounding of R8. Why not just short the R8 (1M) to the case of USB port which is ground. The capacitor and pin shown in picture above do not appear to be ground – they are separated from ground by 5M or more resistance.
Where did you get your isolators from?
Orderfed from eBay and shipped to us from China. Is this not your part?. I got your company name Circuits@Home off the PCB.
Neither of the two circuits allows the computer to recognize any USB peripheral
This is not my part; the board I make is only available from this site and distributors listed on a product page -> https://www.circuitsathome.com/products-page/usb-interfaces/adum4160-usb-isolator-board-populated
Interesting.
I hope there is not someone else manufacturing your board unauthorized. I thought I was purchasing your board but remarketed? They shipped me two new looking boards but with no instruction sheet or paperwork or power supply – a first clue. The PCB is marked with your company label “Circuits@Home 2009” and looks very similar to your photo in above website, but definitely not the same – a few components moved. The board is labeled “USB Isoloator v1.1 Sep.20, 2009 and at bottom has 829D37x2. I thnk it cost me slighly more than the price you list on website.
Is this really not your board. I can buy another from that website if it will actually work. Have you heard of this unauthorized dealer shipping similar parts that do not work?
Thank you for letting me know. The board listed on eBay is a clone. Hope you can return your money.
The boards I sell work fine. They are 100% tested and tests I developed are quite thorough. I have very low rate of returns on these – mostly from folks who needed high-speed, which is not supported.
BTW, I don’t ship power supply with the isolator.
Hi!
I bought the USB isolator fron your european distrobutor. I am going to use it between my PC and USB-dac. I have used it for a while now, but I get sound dropouts all the time. And sometimes the music player stops completely, and I have to restart it o get it working again. Since I have no dropouts when not using the USB-isolator, I suppose it is related to the Isolator. I fed the isolator with current from a linear power supply. Why do I have these dropouts?
Make sure your USB DAC can work at full speed as USB isolator doesn’t support high-speed USB.
I don´t know how to know if it work at full speed, but I can´t se why it should not. It do not utilize any specific drivers, and it do not require any specific version of USB. I
In the beginning the isolator worked for several songs in a row until it freeze. The if I rebooted it worked again, most often. But now it freeze after just a second. I can´t get it to work at all, not even for a while.
Can you check to see if any other device works via an isolator, like a flash drive? Also, are you using homemade or modified factory-made USB cables? What king of power supply are you using?
Hi again Oleg.
I tested with an usb flash stick. I transfered a mp3 file from my laptop to the flash stick and played the file from the stick on my laptop. The USB cable is from Wireworld. It is an “audio” usb cable, it is factory made and not modified. My power supply is a linear labaratory power supply from Manson. It has fixed outputs for both 12 and 5 volt. I wrote a e-mail to the company who has built the DAC. I am not sure they understod my question, but they answered the USB input is specified to 48 khz.
I first read about your USB isolator here – http://www.cicsmemoryplayer.com/index.php?n=CMP.10Soundcard#OptimisingUSBDACs
On this site it is actually said there can be problems with 48 khz – “The device has been successfully tested at 96kHz. Though issues have been reported with some DACs at rates over 48kHz, they are almost certainly caused by the drivers.”
I can´t come to any other conclusion that my problem has to do with the DAC, but I can´t understand why. It ought to work I think.
Hi Oleg, I bought ADuM4160 and make a circuit of my own. I found that when I run host on FULL speed and peripheral on LOW my USB mouse works. But when I run both sides (Host and Peripheral) on FULL speed the mouse doesn’t work and there is no Windows USB error. Why is that? I tried connecting three different memory sticks all I receive is “USB Device Not Recognized”. Do you know why that is?
Thanks
Typically, mouse is low-speed device. Why is it working when the host side is set to full speed, I don’t know. I set both sides to low when I need to work with low speed device.
Yeah I’m not sure, it is not supposed to work with two different speeds. Is it possible to use memory sticks (high speed) with FULL speed selected so that the transfer rates are slower but would still work?
yes, I do this all the time.
But it’s not working for me. I plugged in my 16GB DataTraveller and I get windows device error. Any way to solve this? I have done what you had posted previously but still no change.
It’s hard to suggest anything without seeing your circuit. All I can do is to confirm that AdUM4160 does work with flash drives – one of the QC steps I perform before shipping the board is 1Gb read from some random flash drive connected to a PC through an isolator.
Do you know any reason as to why ADuM4160 would work well at slow speed but when set to FULL it doesn’t react?
Also I see you have an inductor there, what is it for?
Hi Oleg,
I have just assembled one of your isolators. My first experience with smd devices! The IC soldering became out beautiful but the 0.1 caps an resistors are horrible. New experience. I also used a linear regulator and not populated the PS section. Works fine.
But, the lesson really learnt was that I did not now that USB 2 had 3 speed modes. And of course, my device, a PC based scope, requires high speed. Though it does work with full speed refresh rate on the software is unusable.
Anyhow, I am still happy having this tool around. You will never know when you will need it. I use many RS232 devices with the 232 -> USB cable. Now, I know that if I need to isolate the device from the PC, I can.
It is interesting that you are not aware of any isolator that supports high speed. I wander what would be the black magic behind it…
Regards, Charlie.
The AduM4160 has transformers inside and some way ti translate static bus states between sides, Maybe this is too much for high speed. All high-speed isolators I’ve seen so far are optical and cost a lot.
Hi Oleg,
I need help!
I have absolutely no experience in electronics and most of these comments are a foreign language to me.
I am a hobby-music producer and have had a buzzing noise coming from my studio speakers due to interference happening when I plug my laptop charger in and someone recommended I use your USB isolator.
I have a USB audio interface connected to said laptop and have put your USB isolator between the laptop and the USB audio interface.
I still get the USB device not recognized and have tried to do what you have instructed and demonstrated in the picture.
Is there any way you can help me make this work by explaining in layman’s terms?
It is worth noting that I have only used a random power cable I found in a box around the house, should I get a specific power cable?
Really hoping you can help me as this is an expensive mistake for me!
Many Thanks,
Vaughan
Have you already tried to connect other USB devices through the isolator to see if the issue could be specific to a particular device?