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Altera_Forum
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18 years ago

Error: Can't access JTAG chain Error: Operation failed

Dear all, i have a custom board, with stratix II, and Cyclone II, till today i dont have any problem in downloading code, and debug with JTAG port, but today i got "Error: Can't acces...
Altera_Forum's avatar
Altera_Forum
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13 years ago

Has anybody solved this problem? I have a cyclone IV chip that was working fine for a week or so and today it stopped working with the JTAG chain. Boots fine from the existing program in the EPCS device.

I have JTAG powered by 2.5 V which is correct for the cyclone chip. I look at TDI and the CLK pin and it is what you would expect- 2.5 V signals. I look at the TDO and it responds, but the output is only .5V. Obviously this is why it isn't working, but why is it so low?

The programmer works on other boards that run on 3.3V. Did this chip blow out? what could cause this?