ChipScope and XEM3050

First of all, my apologies. I’m posting here because I couldn’t find a discussion board specific for the XEM3050 ( by the way, I take the opportunity to suggest the creation of said board :slight_smile: )

On to my question:

I’m trying to use ChipScope with my XEM3050 board, however acording to the manual, the JTAG connector on this board has a signal level of 2.5 volts. I have the Xilinx JTAG cables but it has a 5V power. Here are its specifications:
Xilinx Parallel Cable IV
Model DLC7
Power 5V – 0.2A
How am I supposed to use this cable with this board? can I connect it directly or do I need a voltage regulator?



Please confirm with the appropriate Xilinx documentation, but the JTAG interfaces are typically driven by the voltage from the target board. The 5v to the Xilinx cable itself is used to drive other logic on the board.

Even Xilinx’s own devices use a variety of JTAG interface voltages, so their own cable needs to be aware and tolerant of this.

Re: XEM3050 and JTAG, please make sure that R17 has been removed in your board. Some units were mistakenly built with this resistor in inserted.

If my board has the R17, what does this mean in terms of using the JTAG interface?

R17 bypasses the switch (J1) and forces it to “USB Programming” mode. It won’t do much for JTAG/ChipScope, but it means you will not be able to boot from PROM.