move, ident

[raggedstone] / dhwk / source / parity_out.vhd

-- J.STELZNER
-- INFORMATIK-3 LABOR
-- 23.08.2006
-- File: PARITY_OUT.VHD

library ieee;
use ieee.std_logic_1164.all;

entity PARITY_OUT is
	port(
		PCI_CLOCK		:in		std_logic;
		PCI_RSTn		:in		std_logic;
		PAR_IN			:in		std_logic_vector ( 2 downto 0);	
		PAR_REG			:in		std_logic;
		SERR_CHECK	:in		std_logic;	
		PERR_CHECK	:in		std_logic;
		OE_PCI_PAR	:in		std_logic;
		OE_PCI_PERR	:in		std_logic;
		PA_ER_RE		:in		std_logic;
		SERR_ENA		:in		std_logic;
		PCI_PAR_IN	:in		std_logic;
		PERR				:out	std_logic;
		SERR				:out	std_logic;
		PCI_PERRn		:out	std_logic;	--	s/t/s
		PCI_SERRn		:out	std_logic;	--	o/d
		PCI_PAR			:out	std_logic		--	t/s
		);
end entity PARITY_OUT; 

architecture PARITY_OUT_DESIGN of PARITY_OUT is

	signal PAR			:std_logic;
	signal PAR_FF		:std_logic;
	signal SERR_FF	:std_logic;
	signal PERR_FF	:std_logic;
  
begin

	PAR		<= ( PAR_IN(2) xor PAR_IN(1) xor PAR_IN(0) ); 

	process (PCI_CLOCK, PCI_RSTn) 
	begin
		if	PCI_RSTn = '0'	then	PAR_FF	<= '0';
															PERR_FF	<= '0';
															SERR_FF	<= '0'; 

		elsif (PCI_CLOCK'event and PCI_CLOCK = '1') then

			PAR_FF	<=	PAR;
			SERR_FF	<=	((PCI_PAR_IN xor PAR) and SERR_CHECK) and PA_ER_RE and SERR_ENA and (not SERR_FF);   
			PERR_FF	<=	((PCI_PAR_IN xor PAR) and PERR_CHECK) and (not PERR_FF);  

		end if;
	end process; 

	SERR			<=  SERR_FF;
	PERR			<=  PERR_FF;

	PCI_PAR		<= PAR_FF				when	OE_PCI_PAR	= '1' else 'Z' ; 
	PCI_SERRn	<= '0'					when	SERR_FF			= '1' else 'Z' ;
	PCI_PERRn	<= not PERR_FF	when	OE_PCI_PERR	= '1' and PA_ER_RE = '1' else 'Z' ;

end architecture PARITY_OUT_DESIGN;