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Altera_Forum
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8 years ago

JTAG connection issue

Hi all, I have a board that configured the Cyclone 4 E device JTAG signals with 2.5V with 100 ohm series resistor on all signals and TMS, TDI pulled up to 2.5V through 2.2k resistors. I ob...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
8 years ago

No. What I want to show with the waveforms is the fact that TDO has low level 1V instead of 0V, which explains why the circuit marginally work with vccio=3.3V but not at all with vccio=2.5V

Plus the variation of signal level, I suspect there is data contention on these signals. According to the schematics, the JTAG signals are also connected to a system controller PLD through series resistors.