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Altera_Forum's avatar
Altera_Forum
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11 years ago

my ep3s200f1152 has been damaged?

Hi,on my subboard there is a fpga(ep3s200f1152),now i cannot access jtag chain,as download is also not work,yesterday i had used it and it can work .My subboard is connected to bottom board which pro...
Altera_Forum's avatar
Altera_Forum
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11 years ago

Just my experience with hot-plug of anything. If you can ensure the GND lines to be connected first - either by special connectors or by using a wire clamp you can hot-plug these stuff. Otherwise the signal voltages on the JTAG Signal lines can increase due to Floating GND potentials (which are most often "somehow" connected either capacitive, by earth groud references, ...)

The datasheet (iirc the cylcone IV one) has some protection diodes connected to the signals to keep the voltages in acceptable range. If you really need to hot-plug the JTAG cable I'd recommed to either route GND by a separate line to equalize signal references or to add the protection diodes.