How to read bits from input in VHDL?

Altera_Forum · ‎01-16-2012

Hi guys..

Can anyone tell me how to read bits from a signal? Let's say I have 16 bits input signal and it's called signal A. How do I read the first 4 bits of the input signal and compare it with signal B which is also 4 bits? Is this possible?

Thanks.

Altera_Forum · ‎01-16-2012

you can access any bits in A:

if A(3 downto 0) = B then

--etc

Altera_Forum · ‎01-16-2012

Thanks Tricky. It worked. =)

But how about if I want to read only 1 bit? Say, there's 01010101 and I want to read the 4th bit.

Thanks.

Altera_Forum · ‎01-16-2012

assuming A is declared something like:

A : in std_logic_vector(7 downto 0);

op <= A(3);

Altera_Forum · ‎01-16-2012

thank Tricky! this helped so much. :)