all debuggers I have used in the past have had the ability to decide whether the debugger will power the DUT or not. I have hunted through ulink and not found it.
if no such function exist, is it OK to cut the Vcc wire from ulink to device??
Erik
Indeed it does - which is why I say that a diagram would be much more helpful!
I had exactly the same question as you a few months back, and had to trace through the schematics to actually be sure.
www.keil.com/.../ulink2_hw_schematic.htm
You need to set the jumer so that "the target hardware provides VCC to the JTAG interface" - which, as I said, is the mirror image of your question; ie, "the JTAG interface does NOT supply power to the target hardware"!
The text is still somewhat misleading: when it says "the JTAG interface" what it actually means is "the buffers between the target hardware and the rest of the uLink"
the jumper is at 'ARM' and the DUT is still powered through the ulink.
just a dirty thought: could it be a signal powering the DUT through a protection diode (ST32) this thought made me measure the DUT Vcc which is ~2.1V when "ulink powered"
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