I am trying to JTAG program a new board which has a UC3A3256. I power everything from USB and the USB is connected to the UC3 and I see the DFU bootloader in windows as a device. A stupid thing I did was to change the placement of the bootloader pin from PB10 to PB1 so I cant use the bootloader after the first programming unless I can change the user pages and that needs JTAG.
So the problem I am having is that the JTAG ICE MK3 does not detect any device. Voltage is ok, but no device. I do not know very much about JTAG signals and what should happen when. Is there a specification or has anyone make a log of how it should look if it works? I have tripple checked the signals and the schematic is the same as the EVK board and the layout looks good as well.
This is generation 5 of the board so it has been working for me for a very long time (~5 years with ~75 boards made). I cant see what I have changed, it should all be the same except routing which should be better on this board since its the first time I cared about trace impedance. Is there a problem using the JTAG ICE MK3 perhaps? I did buy a ISP MK2 for my 8-bit processors because I thought the ICE MK3 was not stable enough.
Any support on problems with the ICE MK3 or on what the signals on the JTAG should look would be appreciated.