Launchpad is not recognized by PC

I have seen this message a lot of times cause by a lot of different reasons.

It is like my old car that would not start. Sometimes it was because I forgot to add gas. Sometimes it was because the carburetor is flooded. Sometime it was cause by fouled spark plugs.

Lior,

When this happens, I usually disconnect the launchpad. Close CCS, and even throw in a reboot sometimes.

After you plug in the launchpad, do you here the USB "da-doot" sounds? If you look under device manager, do you see MSP430 application UART under the com port section?

-Jason

Hi Jason,

I believe the problem is with the board, not the MSP430 chip, since besides being able to program it, the board works perfectly (LEDs, buttons, etc.).  Windows (XP) does not play any sound when I plug the launchpad on, and the device manager does not show the board on the "ports" section.

I tried rebooting the PC, reconnecting the launchpad, reinstalling CCS, using different USB port and even changing the cable, but nothing helped.

As I pointed by my previous message, the symptoms are exactly like the post on the 43oh.com. My guess is that there's a shortage on the chip near the USB connector (marked in red in the 43oh forum's message) , since it gets really hot after plugging the board.

How can I check the integrity of that chip? Did I kill my launchpad?

Lior

Sometimes it is just the USB cable.

However, if it gets hot, there might be a short-circuit.

Lior David said:

Did I kill my launchpad?

Maybe the chip has been soldered 180 degree (sometimes happens, but shouldn't slip the QC then) or there was a problem with the electrical potential (maybe an electrostatic discharge - do you wear wool clothes?) that fried the chip.

My first launchpad suddenly died this weekend while doing some debugging. I noticed the Voltage regulator is getting hot and now only provides 3.3V instead of the 3.6V on my other (still working) launchpad. What is kind of scary about the Design of the Launchpad is that the maximum voltage rating for the TUSB3410 is 3.6V. I think that over time the TUSB chip is getting abused and will eventualy fail. I did order some sample regulators to see if that is actually the problem.

Sicne teh regulator is sourced by teh USB port and it is unlikely that the USB voltage has rised, there's only one reason why the regulator can go hot: someone or something is drawing more current than it can deliver. This also explains the voltage drop. I guess you used amultimeter to measure the voltage. Multimeters are slow and deliver an average voltage. And for high input frequencies, they don't detect anything.

So what might have happened is that an output capacitor is gone bad (soldering problem or if it is an electrolyte one, it may have dried out somehow). This sometimes results in the regulator starting to oscillate. It then is pumping and discharging what remains of output capacity, causing the regulators output transistor to heat up.

Another reson might be that you inserted the target MSP upsode down, and now it is drawing more current that the regulator can drive.

If the regulator is going hot, is there another part that's also heating up?

Henry von Tresckow said:

the maximum voltage rating for the TUSB3410 is 3.6V

Jens-Michael Gross said:

If the regulator is going hot, is there another part that's also heating up?

 

Well, I did some more testing tonight. I took some scope traces of both the 3.6V output and the 5V from my Bench Top supply. There was a 114mv ripple riding on the 3.3V side @127Khz. I also noticed that both the TUSB chip and the Regulator are getting hot. My lauchpad is about 6 months old now. Luckly I have another one to keep working. I also ordered another two as a backup. What has me concened though, it that the new FRAM experimenters borad (a $30 item) uses the same emulator circuit as the Launchpad...(the docs actually refer to it as a FRAUNCHPAD). Would it make sense to send in broken units so TI can do some failure analysis?

Henry von Tresckow said:

here was a 114mv ripple riding on the 3.3V side @127Khz.

It may be due to overload. Reading the LaunchPad schematics, one possible reason for th eproblem could be C6, which is supposed to be 1µF 6.3V. If it was damaged due to a temporary overvoltage, it may have lost much of its capacity and cause the regulator to oscillate. This oscillation, however, might then cause excess currents in the regulator itself as well as the TUSB.

It may as well be as you feared - the output voltage was too much fo rthe TUSB and now it is broken, drawing as much current as the regulator can give until the voltage breaks down to 3.3V. if so, you can try rising R9 from 3.3k to 4.7k, which would result in an output voltage of 3V, or 3.9k for an output voltage of 3.3V. However, if the TUSB is gone, it's gone.

i have the same problem, with 3 different lp's, did anyone find a solution yet?

just tried one of the lps on different machine, with same cord.  finds usbfet.  must be a windows issue....

I have two boards with this issue.I haven't used them in a long time, both tested.

I tried them now on 3 separate computers, one with Windows XP and one Windows 7 and tried also on a Linux machine. Same result, the hardware is not detected at all. 

Does anybody have any idea what causes this? Is it a driver missing or a Windows problem? Or perhaps these boards are just so sensitive that they may get damaged by simply sitting aside?

Any idea would be great.

Thanks

C.

COSTIN LIXANDRU said:

Is it a driver missing or a Windows problem

And it can be the cable. Corroded contacts or broken wires prevent the device from beeing seen by the computer.