disconnect sound on connecting to a project board

Problems uploading, serial connections, BUBs, P4, FTDI cables, etc
Post Reply
tuckera
Posts: 3
Joined: Sun Jan 24, 2010 9:15 am

disconnect sound on connecting to a project board

Post by tuckera » Tue May 01, 2012 5:41 pm

I'm troubleshooting a board that one of my students built for an independent project. We're using the Evil Mad Science Labs "business Card" prototype boards. I used one of these with a ZIF socket to make bootloader/chip test board that works fine. My student used the same circuit to build an instrument that uses the same circuit for serial programming as my programmer board, then he added his signal conditioning circuit and power supply circuit, both of which he had tested separately on a solderless breadboard first.

When I connect his board to a BUB that is already plugged into the computer, I get the disconnect sound. If I try to load a program, I get the classic "avrdude: stk500_getsync(): not in sync: resp=0x00" message. Of course I checked that I had the correct chip selected, and that the programming circuitry was wired correctly, and reheated a bunch of solder joints. No joy.
Then I removed the dual op-amp chip from it's socket, which disconnected what is currently the only other connection to the Arduino chip. That didn't help either. Then I removed the Arduino chip, and I still get the disconnect sound when I connect.

I get 4.93V between Vcc and ground with the BUB connected.

My question is this: what kind of problem would cause the BUB to make the disconnect sound when it is connected to the board? Knowing that would be a huge help in further troubleshooting.

thanks,
andy

paul
Site Admin
Posts: 733
Joined: Mon May 12, 2008 4:19 pm

Re: disconnect sound on connecting to a project board

Post by paul » Tue May 01, 2012 6:58 pm

tuckera,

The Windows disconnect sound? It usually means that it has lost the USB verification chain (probably my terminology is wrong). The most common cause among my students is a short circuit on the board. My thoughts are that you have a short circuit in the board - but you said otherwise. Check the RX and TX and Reset lines and make sure none of them is connected to a power rail. Other than that - I'm kind of clueless. The BUB works fine, and is recognized, all on it's own right? You don't have another power source on the board when testing do you? That could also cause the USB to go out. If you had a voltage collision between a different voltage that was connected to the BUB.

Something is not quite adding up in my mind about your description - so I'm probably missing something

Paul

tuckera
Posts: 3
Joined: Sun Jan 24, 2010 9:15 am

Re: disconnect sound on connecting to a project board

Post by tuckera » Tue May 01, 2012 9:00 pm

Thanks Paul! That's exactly what I needed to know.
It turned out it WAS a short. When I posted, I had been too focused on the programming part of the circuit. When I tested the power on the board, I was testing at a couple of jumpers near the middle of the board, but the student had messed up the wiring for the voltage regulator, which was at the far side of the board from both the serial connector and the point where I was testing.
thanks again,
andy

Post Reply