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Altera_Forum
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10 years ago

Why the output of this Code is 'U' ?

Hi all Why the Sum Value is 'U' in this code ? : LIBRARY ieee; USE ieee.std_logic_1164.all; ENTITY Adder_4_Bit_2C IS PORT( A, B : IN STD_LOGIC_VECTOR(3 DOWNTO 0); Mode : IN STD_LOGI...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
10 years ago

That is Output and mapped to Out port of adder , when A and B and Mode have value , Sum should have value too , Is it correct ?!

I have tested that and Sum shown Output , then I closed project and opened another project with Model-Sim , And Opened this project again and now there is no output !