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I'm new to Cyclone IV design... I accidentally applied 3.3V to the core of a Cyclone IV today, so it's very possible that the chip is fried. When I try to configure it, I get the "Can't access JTAG chain" message. Would that be caused by a fried chip, or is there another problem? Thanks in advance
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Its highly likely you have destroyed the device.
Did you try to measure the power supply voltages? Is the core at the correct voltage after this accident?
There is a JTAG debugger tool in Quartus. You could try toggling TCK, TMS, and TDI and then probe at the FPGA to see if the signals are toggling there. If they are, and TDO does not toggle, then your chip is dead.
If you have another version of this Cyclone IV board, then measure the supply rail impedance. If your toasted board has significantly different impedance than a good board, then thats also a bad sign.
Don't worry, I've made similar mistakes, generally with scope probes accidentally shorting traces together, eg., MAX II CPLDs don't like 12V on their I/O pins either :)
Cheers,
Dave
Honored Contributor
