Power circuit input noise

[rakeshm55]

I am using a Wall wart adapter with 2 pins... wont it be isolated???

[rakeshm55]

Hi,

I contacted FTDI support team with the problem, they suggested to short the USB ground(Device ground) and the shield on my board. After this modification I am not able to hang the device .

I have run the device for 3 days continuously (with a shielded USB cable of lenth 1.75m) and have tried inserting and removing the power adaptor, connecting drill machine to the same power line etc . The device didn't hang.

 By the way I am trying a lengthy USB cable 8m with  shield .

I didnt understand what principle is at work here??

Support team of FTDI suggests a signal noise problem or an ESD problem.