8255芯片 ENTITY a8255 IS PORT( RESET : IN std_logic; CLK : IN std_logic; nCS : IN std_logic; nRD : IN std_logic; nWR : IN std_logic; A : IN std_logic_vector (1 DOWNTO 0); DIN : IN std_logic_vector (7 DOWNTO 0); PAIN : IN std_logic_vector (7 DOWNTO 0); PBIN : IN std_logic_vector (7 DOWNTO 0); PCIN : IN std_logic_vector (7 DOWNTO 0); DOUT : OUT std_logic_vector (7 DOWNTO 0); PAOUT : OUT std_logic_vector (7 DOWNTO 0); PAEN : OUT std_logic; PBOUT : OUT std_logic_vector (7 DOWNTO 0); PBEN : OUT std_logic; PCOUT : OUT std_logic_vector (7 DOWNTO 0); PCEN : OUT std_logic_vector (7 DOWNTO 0) );
