pingp.tdf

这是用AHDL语言编写的一个PCI采集系统的逻辑源码

SUBDESIGN pingp
(
 --data source inputs
 	wr_data[7..0]			: 	INPUT; --from sample data
	wr_addr[14..0]			: 	INPUT;
	wr_clk					: 	INPUT;  --from sample clock(pclk)
  	dfv,ndfv				: 	INPUT; 

 	rd_addr[14..0]			: 	INPUT; --data and address pins
 --rams interface 
 	rama_wr, ramb_wr		: 	OUTPUT;
 	rama_data[7..0]			:	BIDIR;
 	ramb_data[7..0]			: 	BIDIR;
 	rama_addr[14..0]		:	OUTPUT;
 	ramb_addr[14..0]		: 	OUTPUT;
 	rama_oe, ramb_oe		: 	OUTPUT;
 	rd_data[7..0]			: 	OUTPUT; 

)

VARIABLE
 	data_outa[7..0]		: 	TRI;
 	data_outb[7..0]		: 	TRI;
 	oea					: 	NODE;
 	oeb					: 	NODE; 
       
BEGIN


 	oea = dfv;             -- if dfv is high, rama write, ramb read
 	data_outa[].oe = oea;
 	data_outa[].in = wr_data[];
 	rama_data[] = data_outa[].out;
 	oeb = ndfv;
 	data_outb[].oe = oeb;
 	data_outb[].in = wr_data[];
	ramb_data[] = data_outb[].out;

 	IF(dfv) THEN
 		rama_addr[] = wr_addr[];
		rama_wr = !wr_clk;
		ramb_addr[] = rd_addr[];
		ramb_wr = VCC;
		rd_data[] = ramb_data[];

 	ELSE
		rama_addr[] = rd_addr[];
		rama_wr = VCC;
		ramb_addr[] = wr_addr[];
		ramb_wr = !wr_clk;
		rd_data[] = rama_data[];

	END IF;

 	rama_oe = dfv;
 	ramb_oe = ndfv;
         
END;