Cyclone III stuck at POR?

Hello FvM,

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Regarding unusual "special" configuration circuits, e.g. pulling nCONFIG high, as long as you do't know the exact internal circuit connected to the pins and their operation, I would avoid these.

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Yes, I think that's a good hint. I'll try to simplify the config circuit to be closer to the Altera recommended circuit.

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I wonder, if the ferrite bead without decoupling capcitor may cause unwanted ripple or even overvoltages on the device side supply node.

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The ferrite's resistance is too low to cause such effects. But the ferrite isn't useless, it will kill most of the noise caused by the device. For the EPCS device it's not really needed, beacuse it's only operated during the startup phase and does not cause continous noise. But especially for oscillators the ferrite significant improves EMI compliance. The reason why the decoupling capacitor is placed before the ferrite is that if it's placed directly at the pin, the noise will flow through the capacitor to the ground plane and cause EMI.

That's how they told me in the EMI seminar, anyway.

Regards,

Jürgen