Question

Write an entity declaration for a combinational circuit named bcd2xs3 that converts a BCD

input code for a decimal digit to an excess three (XS3) output code for a decimal digit. The
input code is represented by four scalar signals of type std_logic. These signals have the
identifiers D, C, B, and A, where D is the most significant bit. The output is represented by four scalar signals of type std_logic. The identifiers for the outputs are XS3, XS2, XS1, and XS0.

Answer 1

The entity declaration for the combinational circuit named bcd2xs3 can be written as follows: entity bcd2xs3 is port ( D, C, B, A : in std_logic; XS3, XS2, XS1, XS0 : out std_logic ); end bcd2xs3.

Step-by-step explanation:

The entity declaration for the combinational circuit named bcd2xs3 can be written as follows:

entity bcd2xs3 is
port (
D, C, B, A : in std_logic;
XS3, XS2, XS1, XS0 : out std_logic
);
end bcd2xs3;

In this declaration, the circuit has four input signals: D, C, B, A of type std_logic, representing a BCD input code. It also has four output signals: XS3, XS2, XS1, XS0, also of type std_logic, representing an excess three (XS3) output code for a decimal digit.