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Altera_Forum's avatar
Altera_Forum
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15 years ago

EP3C25 nStatus 1V

I have five EP3C25 borad, 3 of them are working well. But the rest 2 will sometimes boot fail. The working mode is AS or fast AS from EPCS4. There're 10K pull up on nStatus, nConfig, Conf_done, MSELs...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

The manual says 2.5V so connecting them to 3V isn't ok. That said I'm not sure it would have any real impact on the system. The only two issues I see would be with clamping diodes (but then, it's only 0.5V...) and a problem due to power supply ordering. Although in the latter case maybe the por circuitry prevents the FPGA from reading the MSEL pins before all the supplies are at their nominal level.

Do the FPGA's on the failing boards answer properly through JTAG?