Hi,

I have problems when I try to connect to LPC1768 on a custom board with a J-link (Hardware v.8.0, DLL v.4.80). Jlink doesn't see the controller at all, and I think the problem is in hardware, but I can't understand, where exactly.
I see with an oscilloscope, that TCK has level of 0,77 V when jlink is connected. If i disconnect only this wire (others remain connected), the level is +3,3 on Jlink side, and i can see the clock going. On thу board side level is 0. It seems, that the TCK pin has a too strong pull-down on board side. I have a pull-down resistor on the line, but the performance of the board does not change with the value of this resistor (tried 10k, 5k, 100k and no resistor). I have no other elements on TCK line.
I have several such boards, and it seems unlikely, that the problem is in controller. Also I have another board with same controller, that worked properly with a different debug device, but behaves the same way with the current Jlink.
Maybe there is some settings that i'm missing, so Jlink can handle such pulldown? Or, if you know, there is a way to change this internal controller's pulldown before it is programmed?

Update:
Another J-link with older hardware (hardware v.3.0 and firmware from 2006) connected to the same board with the same cabling without any problems and allowed to program and debug it. Therefore, I still suspect J-Link as the faulty element. (although the first, "faulty" J-link also programmed one of our other boards, so it functions OK.)