// --------------- RAM?ROM ----------------------------------------
module ram( data, addr, ena, read, write );
inout [7:0] data;
input [9:0] addr;
input ena;
input read, write;
reg [7:0] ram [10'h3ff:0];

assign data = ( read && ena )?  ram[addr] : 8'hzz;

always @(posedge write)
begin
ram[addr]<=data;
end
endmodule