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Altera_Forum
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16 years ago

Error in JTAG chain before reprogramming

I'm trying to reprogram a MAX II CPLD with USB Blaster in JTAG mode. When I click Auto Detect appears error message “Unable to scan device chain. Can’t scan JTAG chain.” Testing JTAG chain with...
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Altera_Forum
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16 years ago

There shouldn't be glitches on TDO. If they are actually present (not only caused by limited oscilloscope resolution), something is wrong with your hardware. E.g. an unsufficient ground connection creates ringing clock edges at TCK.