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Certain output signals are default high after power up

FXion
Beginner
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I have a customized MAX 10 board with 10M08DAF256C8G chip. One of the output signals driven by the FPGA pin P5 is high right after power up before the FPGA is programmed. After programming, the signal is low. Don't know what's going on, guess there is something inside the FPGA going on like a weak pull up resistor. Don't know how to fix this to bring the signal low after power up before programming. Thanks.

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Nooraini_Y_Intel
Employee
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Hi Fxion,

 

There is weak pull up on each MAX 10 IO pins however these IO pins are ​tri-stated when power up.  The POR circuit monitors the voltage level of power supplies and keeps the I/O pins tri-stated during power up. The weak pull-up resistor in MAX 10 device I/O elements (IOE) keeps the I/O pins from floating.

 

Regards,

Nooraini

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