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i can't download program into EP2C5 via jtag,so i test it use Quartus II tool named jtag chain debugger ,Quartus II know the device is EP2C5 TMS TCK TDO is ok ,but there is a Fork on TDI,then i use oscilloscope to test Circuit,
i found the wave of TMS TCK TDO is good ,but the TDI is not good , the wave of TDI is in the attachmenthigh level is 3.3V ,that right,but the low level is 1.68V (the half of 3.3),not 0V ,can anyone tell me why?
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What kind of pull-up do you have on TDI? Isn't it too small?
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the pull-up is 1k 0603 they are ame on TCK and other
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okay... it could be the jtag cable that has a bad driver then... can you test it on another board?
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