Question

Write VHDL code that represents a T flip-flop with an asynchronous clear input. Use behavioral code, rather than structural code.

Answer 1

The VHDL code provided describes a T flip-flop with an asynchronous clear using a process block that reacts to changes in the clock and clear signals to update the output.

Step-by-step explanation:

The student is asking for VHDL code that implements a T flip-flop with an asynchronous clear input using behavioral code. In VHDL, a process block can be used to describe the behavior of the T flip-flop. A typical behavioral description includes reading the current state, checking input conditions, and then determining the next state of the flip-flop. Here is a simple VHDL code example for a T flip-flop with an asynchronous clear:

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity T_flip_flop is
Port ( T : in STD_LOGIC;
clk : in STD_LOGIC;
clr : in STD_LOGIC;
Q : out STD_LOGIC);
end T_flip_flop;

architecture Behavioral of T_flip_flop is
begin
process(clk, clr)
begin
if clr = '1' then
Q <= '0';
elsif rising_edge(clk) then
if T = '1' then
Q <= not Q;
end if;
end if;
end process;
end Behavioral;

The process is triggered by changes in the clock (clk) or the clear signal (clr). If the clear signal is asserted (clr = '1'), the flip-flop's output Q is asynchronously set to '0'. Otherwise, on the rising edge of the clock and if T is '1', then the output Q toggles its value.