Smoked a BUB :[

Problems uploading, serial connections, BUBs, P4, FTDI cables, etc
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Posts: 3
Joined: Mon Feb 15, 2010 5:42 am

Smoked a BUB :[

Post by Bitrex »

I was working on a project the other day, where I'm using the BUB to download software to an AVR microcontroller with a bootloader via a serial link. The BUB had its ground connected to the ground of the project board, and the RX and TX lines were connected to the respective pins of the AVR. The board was powered off a 15 volt supply being regulated by a 5 volt regulator on the board - no power was being supplied by the BUB board itself. Everything was working out fine with this situation, but after disconnecting the project board for testing on my workbench with a scope and reconnecting things again, something went wrong. I sent the command to upload the software to the bootloader and immediately noticed the "burning electronics" scent. I cut the power to everything, and found that it was the FTDI chip that had gotten extremely hot.

Unfortunately, while my PC will still recognize the board, it won't upload anymore; I'm pretty sure either the RX or TX lines must be fried. Without knowing the details of the project I suppose it's hard to speculate, but does anyone have any ideas about what might have gone wrong? I'm positive I didn't connect the supply to the RX or TX lines accidentally, and the project board still works fine; no shorts on it. The BUB board itself wasn't supplying any power to the circuit. I guess the only way it could have happened is if somehow the supply got on to the RX or TX lines, but I don't see how!
Posts: 9
Joined: Sat Apr 02, 2011 1:20 pm

Re: Smoked a BUB :[

Post by stevech »

not much evidence to go on. But first guess is the FTDI chip's Vcc went far too high, like the regulator failed or somehow 15V from a power source got applied to where 5V belongs.
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