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Altera_Forum
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11 years ago

Function to_unsigned returns only zeros

Hello, I'm programming a FIR Filter in VHDL and I want to insert stuck on errors in the taps.. so, I did this: SIGNAL tap0, tap1, tap2, tap3 : INTEGER :=0 ; SIGNAL error : INTEGER...
Altera_Forum's avatar
Altera_Forum
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11 years ago

--- Quote Start ---

SIGNAL tap3std : std_logic_vector(to_unsigned(tap3, 8));

--- Quote End ---

In the declaration you should give the size of the vector, not the initial value:

SIGNAL tap3std : std_logic_vector(15 downto 0);

In this example tap3std has 16 bits. You can give an initial value to a signal that is a register.

The only exception are the testbenches where you can do that. This initial value is assigned in the reset condition:

process(clk)

begin

if( rst = '1' ) then

tap3std <= std_logic_vector(to_unsigned(....

elsif( clk'event and ....