Fried USB port?

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smkoberg
 
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Fried USB port?

Post by smkoberg »

Hi All;
Got a new laptop a few weeks ago and I think I may have fried 2 of the 3 USB ports...
I was working on a project using a Boarduino, 16x2 LCD screen, and a stepper motor which is supposed to get power from a wall-wart run through an L293D.

The stepper is rated 2.8V at 1.5A, so I was using the 5V, 2A wall-wart to power the stepper, along with a voltage regulator to drop the voltage down, and have the USB/FTDI cable power the Boarduino and the LCD screen.

I had made sure the +power coming from the USB and the wall-wart didn't get mixed up/had the USB power on one breadboard rail, and the wall-wart power on another rail, and from what I understand, you are supposed to tie all grounds together. So I did.

When I first connected the boarduino to the laptop, the Arduino IDE recognized something was connected to COM3, and I uploaded one of the stepper examples to see if the motor was wired up correctly, as soon as the uploading was finished, the IDE lost communication with the board, and now two out of three of my USB ports don't work for data I/O.

I connected a usb mouse to the messed up USB ports to see if they were fried, and I'm getting the LEDs in the mouse working, so I know power is getting to the mouse, but the mouse doesn't effect the cursor on the monitor. I also am unable to get data from a thumb/flash drive to the ports; the computer doesn't recognize somethings connected.

Does this sound like I overloaded the USB ports somehow with the wall-wart?

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zener
 
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Re: Fried USB port?

Post by zener »

I don't know the answer, but I seem to remember a nearly identical question recently. You might try searching the forum.

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cstratton
 
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Re: Fried USB port?

Post by cstratton »

At first glance it's surprising that you could fry the data lines while the power is still good - I'd be more likely to suspect killing the power supply to the port.

But if you are dealing with a stepper, you have a serious inductor, and that can kick back well above the supply voltage every time a winding is turned off. Without appropriate catch diodes - or on a breadboard where the circuit is always falling apart as you work on it, it could be a recipe for trouble.

One thing you might consider in the future is using an ordinary USB-RS232 adapter instead of the ftdi cable, and then use a level translator in your project - while not immune to everything, RS232 drivers/receivers are designed to be connected to exposed ports, and use 12-15v signals, so they may be a little more robust.

You can also use a throwaway usb hub - not perfect insurance, but it's one more piece of inexpensive gear standing between your experiment and something that is expensive to replace.

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abqlewis
 
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Re: Fried USB port?

Post by abqlewis »

Whether the ports are blown or not, this is a wake-call for me (but I am sorry if yours are gone). I like the idea of a sacrificial USB Hub. Maybe a backup so I can trade them out. One more thing to change out of the loop during debug. But could it affect the USB protocol in some small way (different driver, different COM port #, etc)?

Thanks,
Michael

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cstratton
 
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Re: Fried USB port?

Post by cstratton »

A USB hub does change the situation somewhat, but it's less likely to be an issue with something that is proper USB like the ftdi cable, than it is with some hack of a soft-usb expirment-in-progress. Though, for that matter, when on the edge of the specs, adding a hub may be as likely to help the communication as hurt it - it's all a matter of which is more tolerant, that or the computer.

I do have a cheap hub (a freebie bearing a distributor's imprint) which has the annoying habit of reconnecting every client that is on it, anytime one of its clients is plugged. This is bad if there's a terminal program open on an ftdi cable or other usb serial on the hub, while you plug something else like a usb project, because then the usb-serial reconnects and gets assigned a new port name since the original is tied up by the still-running terminal program. But most of the time one only has one USB accessory involved in the project.

smkoberg
 
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Joined: Tue Aug 11, 2009 3:45 am

Re: Fried USB port?

Post by smkoberg »

Interesting update:
Over the past couple of days, I've been dreading the potential disassembly of my laptop to see if I could figure something out about the two USB ports, all the while using my mouse in the one working USB port. Today, I decided to hook up the mouse to one of the 'fried' USB ports to confirm that they weren't working and windows gave me a 'searching for device drivers' message... After the drivers installed, the mouse works fine. I'm going to connect my FTDI cable and boarduino and upload the blink sketch to see if it all works like its supposed to.

silly windows.

smkoberg
 
Posts: 55
Joined: Tue Aug 11, 2009 3:45 am

Re: Fried USB port?

Post by smkoberg »

Well, the USB ports work fine.
I connected the FTDI cable and windows gave me a message about not being able to find the correct driver, so I went into the device manager to find the FTDI cable and update the drivers, which window told me were up to date. I plugged up the boarduino and uploaded the blink sketch and it ran fine.
I understand something may have happened when I had the stepper motor, boarduino, LCD screen, and wall-wart connected, but not having anything change in the meantime and having the issue sort itself out is confusing. Whatever, I'm just glad its working.

Now, if you'll excuse me, I need to figure out away to take over the world with this stuff...

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baldengineer
 
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Re: Fried USB port?

Post by baldengineer »

Modern USB host chipsets will shutdown power to a port that is drawing too much current. It is possible you tripped some form of safety.

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