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State of GPIO when BF is not powered up

Question asked by lee1983 on Oct 27, 2010
Latest reply on Dec 1, 2010 by Prashant

Hi,

 

The hardware manual of BF54x tells me that GPIO pins are in input mode after reset. Upon my understanding,  all of these GPIO pins should be in tri-state if no code sets them as input/output during or after BF powers up. What mode are GPIO pins in if Blackfin is not powered up at all? What is the impedance of GPIO?

 

The reason why I get this question is the signal connecting to PG6 will drop from high level to low level as long as system powers up except BF. There is 4.7k pull-up resistor (3.3V) connecting to PG6 in system.

 

Thanks.

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