cal_ctl.vhd

xinlinx s vhdl code model and user guider

                  elsif (state = idleD1) then
		     if (hxSamp1 = '1' and prevSamp = '0') then
			d1Shft <= zoShft;
			selTap <= tap3;
			waitOneCycle <= '1';
			state <= idleD2;
			rstate <= idleReset;
			resetDcm <= '1';
		     elsif (hxSamp1 = '0' and prevSamp = '1') then
			d1Shft <= ozShft;
			selTap <= tap3;
			waitOneCycle <= '1';
			state <= idleD2;
			rstate <= idleReset;
			resetDcm <= '1';
		     elsif (hxSamp1 = '0' and prevSamp = '0') then
			--- increment phase shift delay
			psEn <= '1';
                        psinc_val <= '1';
			state <= waitDcmD1;
			prevSamp <= '0';
		     elsif (hxSamp1 = '1' and prevSamp = '1') then
			--- decrement variable delay
			psEn <= '1';
			psinc_val <= '0';
			state <= waitDcmD1;
			prevSamp <= '1';
		       end if;
 		  elsif (state = waitDcmD1) then
		     psEn <= '0';
		     if (psDoneReg = '1') then
			state <= idleD1;
		     end if;
                  elsif (state = idleD2) then
		     if (hxSamp1 = '1' and  prevSamp = '0') then
			d2Shft <= zoShft;
			selTap <= tap4;
			waitOneCycle <= '1';
			state <= idleD3;
			rstate <= idleReset;
			resetDcm <= '1';
		     elsif (hxSamp1 = '0' and prevSamp = '1') then
			d2Shft <= ozShft;
			selTap <= tap4;
			waitOneCycle <= '1';
			state <= idleD3;
			rstate <= idleReset;
			resetDcm <= '1';
		     elsif (hxSamp1 = '0' and prevSamp = '0') then
			--- increment phase shift delay
			psEn <= '1';
			psinc_val <= '1';
			state <= waitDcmD2;
			prevSamp <= '0';
		    elsif (hxSamp1 = '1' and prevSamp = '1') then
			--- decrement variable delay
			psEn <= '1';
			psinc_val <= '0';
			state <= waitDcmD2;
			prevSamp <= '1';
		     end if;
 		  elsif (state = waitDcmD2) then
		     psEn <= '0';
		     if (psDoneReg = '1') then
			state <= idleD2;
		     end if;
                  elsif (state = idleD3) then
		     if (hxSamp1 = '1' and  prevSamp = '0') then
			d3Shft <= zoShft;
			selTap <= tap5;
			waitOneCycle <= '1';
			state <= idleD4;
			rstate <= idleReset;
			resetDcm <= '1';
		     elsif (hxSamp1 = '0' and prevSamp = '1' ) then
			d3Shft <= ozShft;
			selTap <= tap5;
			waitOneCycle <= '1';
			state <= idleD4;
			rstate <= idleReset;
			resetDcm <= '1';
		     elsif (hxSamp1 = '0'and prevSamp = '0') then
			--- increment phase shift delay
			psEn <= '1';
			psinc_val <= '1';
			state <= waitDcmD3;
			prevSamp <= '0';
                     elsif (hxSamp1 = '1' and prevSamp = '1') then
			--- decrement variable delay
			psEn <= '1';
			psinc_val <= '0';
			state <= waitDcmD3;
			prevSamp <= '1';
		        end if;
 		  elsif (state = waitDcmD3) then
		     psEn <= '0';
		     if (psDoneReg = '1') then
			state <= idleD3;
		     end if;
		  elsif (state = idleD4) then
		     if (hxSamp1 = '1' and prevSamp = '0') then
			d4Shft <= zoShft;
			selTap <= tap6;
			waitOneCycle <= '1';
			state <= idleD5;
			rstate <= idleReset;
			resetDcm <= '1';
		     elsif (hxSamp1 = '0' and prevSamp = '1' ) then
			d4Shft <= ozShft;
			selTap <= tap6;
			waitOneCycle <= '1';
			state <= idleD5;
			rstate <= idleReset;
			resetDcm <= '1';
		     elsif (hxSamp1 = '0' and prevSamp = '0') then
			--- increment phase shift delay
			psEn <= '1';
			psinc_val <= '1';
			state <= waitDcmD4;
			prevSamp <= '0';
		     elsif (hxSamp1 = '1'and prevSamp = '1') then
			--- decrement variable delay
			psEn <= '1';
			psinc_val <= '0';
			state <= waitDcmD4;
			prevSamp <= '1';
		     end if;
                  elsif (state = waitDcmD4) then
		     psEn <= '0';
		     if (psDoneReg = '1') then
			state <= idleD4;
		     end if;
		  elsif (state = idleD5) then
		     if (hxSamp1 = '1' and prevSamp = '0') then
			d5Shft <= zoShft;
			selTap <= tap1;
			waitOneCycle <= '1';
			state <= idleD0;
			rstate <= idleReset;
			resetDcm <= '1';
		     elsif (hxSamp1 = '0' and prevSamp = '1' ) then
			d5Shft <= ozShft;
			selTap <= tap1;
			waitOneCycle <= '1';
			state <= idleD0;
			rstate <= idleReset;
			resetDcm <= '1';
		     elsif (hxSamp1 = '0' and prevSamp = '0') then
                        ---  increment phase shift delay
			psEn <= '1';
			psinc_val <= '1';
			state <= waitDcmD5;
			prevSamp <= '0';
		     elsif (hxSamp1 = '1' and prevSamp = '1') then
			---- decrement variable delay
			psEn <= '1';
			psinc_val <= '0';
			state <= waitDcmD5;
			prevSamp <= '1';
		     end if;
 		 elsif (state = waitDcmD5) then
		     psEn <= '0';
		     if (psDoneReg = '1' ) then
			state <= idleD5;
		     end if;
		     --- end else if (state == `idleDone) begin
		  end if;
	       end if; --- else: !if(wait4Cycle)
	       
	    end if; ----  else: !if(resetDcm)

           if (psDoneReg = '1' and rstate /= waitReset) then
	      if (psinc_val = '1') then
                   posPhShft <= posPhShft + 1;
	      else 
                  negPhShft <= negPhShft + 1;
	       end if;
            end if;

	 end if;---- // if (dcmlocked)
	 
      end if;--- // else: !if(reset)
      end if;
  
end process;      
   

--- Logic to figure out the number of tap delays to use for dqs
 ---  generate the output tapForDqs
 
 process(clk)
 begin            
     if clk'event and clk = '1' then
        if reset = '1' then
             lPtr <= "0000";
             uPtr <= "0101";
             tapForDqs <= defaultTap;
             inTapForDqs <= defaultTap;
             newTap  <= defaultTap;
             midPt <= "0011";
             okSelCnt <= '0';
         else
            if (d0Shft > lBound) then
               lPtr <= "0000";
            elsif (d1Shft > lBound) then
               lPtr <= "0001";
            elsif (d2Shft > lBound) then
               lPtr <= "0010";
	    elsif (d3Shft > lBound) then
               lPtr <= "0011";
	    elsif (d4Shft > lBound) then
               lPtr <= "0100";
	    else 
               lPtr <= "0101";
            end if;
             
             if (d5Shft < uBound) then
                uPtr <= "0101";
	     elsif (d4Shft < uBound) then
                uPtr <= "0100";
	     elsif (d3Shft < uBound) then
                uPtr <= "0011";
	     elsif (d2Shft < uBound) then
                uPtr <= "0010";
	     elsif (d1Shft < uBound) then
                uPtr <= "0001";
	     else 
                uPtr <= "0000";
             end if;

           midPt(3 downto 0) <= ( uPtr(3 downto 0) + lPtr(3 downto 0) );

  --------------------
            
           case midPt(3 downto 1) is

               when "000" =>
                     inTapForDqs <= tap1;
	       when "001" =>
                     inTapForDqs <= tap2;
	       when "010" =>
                     inTapForDqs <= tap3;
	       when "011" =>
                     inTapForDqs <= tap4;              
	       when "100" =>
                     inTapForDqs <= tap5;
	       when "101" =>
                     inTapForDqs <= tap6;
	       when others =>
                     inTapForDqs <= inTapForDqs;
	 end case;  --- case(midPt[2:0])
        
         ---  tap output shouldn't change unless the same tap value is selected n number of times.

	 newTap <= inTapForDqs;

	 if (inTapForDqs = newTap) then
	    
	    if (wait4Cycle = '1') then
              selCnt <= selCnt + 1;
             end if;
	    if (selCnt = slipCnt) then
               okSelCnt <= '1';
	    else okSelCnt <= '0';
             end if;
	  else 
	    selCnt <= "0000";
	    okSelCnt <= '0';
	 end if;
	    	 
	 if (okToSelTap ='1' and okSelCnt = '1') then
               tapForDqs <= newTap;
         end if;
        end if;
       end if;
      end process;
     


	
end arc_cal_ctl;