decoder.vhd

新买的书

-- Memory decoder module for the Mobile Videophone Thesis. It is
-- set to send the output high when the address is 0x01000000.
library ieee;
use ieee.std_logic_1164.all;
entity MEM_DEC is
port(XA21,XA20,XA5,XA4,XA3,XA2,XRE,XOE,XWE,XCE1: in BIT; DOE: out BIT);
end MEM_DEC;
architecture behavioral of MEM_DEC is
begin
process (XA21,XA20,XA5,XA4,XA3,XA2,XRE,XOE,XWE,XCE1)
variable READ,WRITE: BIT;
begin
READ := not XA21 and not XA20 and not XA5 and not XA4 and not XOE and not
XRE and XWE and not XCE1;
DOE <= READ and not XA3 and not XA2;
end process;
end behavioral;