Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor
use IEEE.numeric_std.all; -- for the unsigned type
invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet.
-- Source: http://en.wikipedia.org/wiki/VHDL library IEEE; use IEEE.std_logic_1164.all; use IEEE.numeric_std.all; -- for the unsigned type entity COUNTER is generic ( WIDTH : in natural := 32); port ( RST : in std_logic; CLK : in std_logic; LOAD : in std_logic; DATA : in std_logic_vector(WIDTH-1 downto 0); Q : out std_logic_vector(WIDTH-1 downto 0)); end entity COUNTER; architecture RTL of COUNTER is signal CNT : unsigned(WIDTH-1 downto 0); begin process(RST, CLK) is begin if RST = '1' then CNT <= (others => '0'); elsif rising_edge(CLK) then if LOAD = '1' then CNT <= unsigned(DATA); -- type is converted to unsigned else CNT <= CNT + 1; end if; end if; end process; Q <= std_logic_vector(CNT); -- type is converted back to std_logic_vector end architecture RTL; process begin wait until START = '1'; -- wait until START is high for i in 1 to 10 loop -- then wait for a few clock periods... wait until rising_edge(CLK); end loop; for i in 1 to 10 loop -- write numbers 1 to 10 to DATA, 1 every cycle DATA <= to_unsigned(i, 8); wait until rising_edge(CLK); end loop; -- wait until the output changes wait on RESULT; -- now raise ACK for clock period ACK <= '1'; wait until rising_edge(CLK); ACK <= '0'; -- and so on... end process;