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Altera_Forum's avatar
Altera_Forum
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15 years ago

Is chip fried? Can't access JTAG chain

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 c...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

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This information is inconsistent. If an ohm-meter indicates 0-Ohms between the core voltage and ground, then its a short, and you would not see a voltage when you turn the supply on. (You be making the impedance measurement with the power off).

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What I meant about 0-ohms was just measuring the 3.3V-rail alone, from one end to the other. If I go 3.3V-to-ground, it's kind of weird. The reading starts at 0.5-Mohms and slowly climbs up, until displaying Overload. I guess that means I have a really weak short between 3.3 and ground? Probably another sign the chip is busted.

Thank you very much. I'll suck it up and buy a new one now :/