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Async Resets for Flops -> what polarity is preferable?

ldm_as
Novice
497 Views

Hi All,

 

As for the Async Reset for the flops - what polarity is preferable (posedge or negadge)?

 

If I don't define a default value for FF, will it be '0'?

 

Thank you!

 

0 Kudos
1 Reply
Kenny_Tan
Moderator
170 Views

Usually would be negedge

 

always @ (negedge <reset> or posedge <clock_signal>)

begin

// Reset whenever the reset signal goes low, regardless of the clock

if (!<reset>)

begin

<register_variable> <= 1'b0;

end

// If not resetting, update the register output on the clock's rising edge

else

begin

<register_variable> <= <data>;

end

end

 

You can right click the vhdl -> insert template -> verilog hdl-> logic -> register

 

Look into the details.

 

You can also look into https://www.intel.co.jp/content/dam/www/programmable/us/en/pdfs/literature/quartus2/qts_qii51006.pdf page 9-4

 

If you don't defined, there will be no reset port in your flop flop.

 

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