标签: 十进制计数器

LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.ALL; USE IEEE.STD_LOGIC_ARITH.ALL; USE IEEE.STD_LOGIC_UNSIGNED.ALL; --************************* ENTITY counter10 is PORT( CP:IN Std_Logic; Qout: OUT STD_LOGIC_VECTOR( 3 DOWNTO 0) ); END counter10; --*************************** ARCHITECTURE demux4_behave OF counter10 IS SIGNAL RST:STD_LOGIC; SIGNAL QN:STD_LOGIC_VECTOR(3 DOWNTO 0); BEGIN proceSS(CP,RST) BEGIN IF RST='1'THEN QN="0000"; ELSIF CP'EVENT AND CP='1'THEN QN=QN+1; END IF; END PROCESS; RST='1'WHEN QN="10" ELSE '0'; Qout=QN; END demux4_behave;