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Altera_Forum
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17 years ago

Cyclone II I/O Output at Power Up!

Using a EP2C8F256C6 and found that during power up there is a 3.3V pulse coming out from the I/O pins. Pulse lasts for ~10ms. As I understand, during power up, pins should be tri-stated but I'...
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Altera_Forum
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17 years ago

The i/o are really tri-stated at power-up, reset, configuration and initialization (to be verified).

In cyclone II device, there are a weak pull-up resistors(~25kOhms) wich pull the pins high.

See datasheet and "configuration handbook"

Except for some pins :

dev_oe which goes low (open drain) until the first data configuration frame comes. If you use dev_oe as an user I/O pin.