minusself23to0.v

verilog描述 23：59：59-00：00：00自减计时器 按set键

`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company: 
// Engineer: 
// 
// Create Date:    15:17:31 04/12/2008 
// Design Name: 
// Module Name:    minusself23to0 
// Project Name: 
// Target Devices: 
// Tool versions: 
// Description: 
//
// Dependencies: 
//
// Revision: 
// Revision 0.01 - File Created
// Additional Comments: 
//
//////////////////////////////////////////////////////////////////////////////////
module minusself23to0    (clk  , set ,  adj  ,  cf ,  timmer , mode ,sback, mback, hback);
    input clk;
	 input set;
	 input adj;
	 input cf;
	 input timmer;
	 input mode ;
    output [7:0] sback;
    output [7:0] mback;
    output [7:0] hback;
reg[7:0]  hcb=8'h23 ,  scb=8'h59  , mcb=8'h59 ;   //cb is clock back
reg[7:0]  hback=8'h23 ,  sback=8'h59  , mback=8'h59 ; 


reg[3:0] setcb = 4'h0;
reg   timmergo = 1   ;
reg[1:0] modestate = 2'b10  ;


//reg[7:0] dclk1 = 8'b0000000  , dclk2 = 8'b0000000 , dclk3 = 8'b0000000 ,dclk4 = 8'b0000000 ,dclk5 = 8'b0000000;
reg[7:0] count1 = 0;
reg reset = 0 ;
reg[1:0]  transfer = 00;
reg clh =0 ,cls =0 ;







//-------------------------control singal timmer ,    describe-------------------------------
always @(posedge clk)

begin
if(timmer == 1)
  begin    
	 
	 timmergo = timmergo + 1;                       //timmergo = 0 is stop
  end
  
else if(mode == 1 & setcb == 0)
   modestate = modestate + 1;

end

 
 


//----------------------------------no singal 60 seconds  or  get mode singal ----------------------------------------------

always @(posedge clk)
begin
reset = 0;
begin
 if(adj==0 & cf ==0 & set ==0 )
   begin
       if (count1 == 59)  
	     	begin
				
			reset = 1;
			end
        else
		  count1 = count1 + 1 ;
		  
	end
	
 else if ( adj==1 )  
    count1=0;
	 
 else if ( cf==1 )  
    count1=0;
	 
 else if ( set==1 )  
    count1=0;
 end 
end




/*

//-----------------------set initial  hour ,minute , second------------------------

always @(posedge clk )
    	 
     
	  //begin to start ,and going ,if going to 00:00:00,alarm and out of this state
	  //in this state , if we give set ,begin to set1,2,3 hour , minute , second ,out ; if @timmer ,go back

 begin

if(reset==1)
  setcb = 0;
else
  begin 
   if ( set==1 )
       begin
       setcb = setcb + 1 ;   
          if(setcb==1)
            begin
            hcb = hback;
		      mcb = mback;
		      scb = sback;
            end
            				
       end     
   

   else
    

      if(modestate==2'b10 & setcb>0)
  
	   transfer = 2'b00		;
	  
	begin 
     
	  
	  
	 	  case(setcb)    
		4'h1:                                        //hour set
		  begin
		   if(timmer == 1)
   		 setcb = 0;
	     else
			 begin
			     if(adj==1 & cf ==0)                                       
			       begin
			           
	                       if(hcb[7:4]==4'h2)                            
	                         begin
	                           if(hcb[3:0]>= 4'h3)
							          begin
										 hcb = 0;
		                         end
							         else
							         hcb[3:0]=hcb[3:0]+1;
					                            
			                   end    			        
		                   else  
                           begin
		                     if(hcb[3:0] == 4'h9)
							         begin
							      hcb[3:0] =0;
							      hcb[7:4] = hcb[7:4]+1;
					               end
                           else							
					            hcb[3:0]=hcb[3:0]+1;
                           end 
		             
				         transfer = 2'b01;		 
				      end

             else if(adj == 0 & cf == 1)                              
                begin
					      if(hcb[7:4]==4'h0)                            
	                         begin
	                           if(hcb[3:0]== 4'h0)
							          begin
										 hcb[7:4] = 2;
		                        hcb[3:0] = 3;
										 end
							         else
							         hcb[3:0]=hcb[3:0] - 1;
					                            
			                   end    			        
		                   else  
                           begin
		                     if(hcb[3:0] == 0)
							         begin
							      hcb[3:0] =9;
							      hcb[7:4] = hcb[7:4] - 1;
					               end
                           else							
					            hcb[3:0]=hcb[3:0] - 1;
                           end 	
                   transfer = 2'b01;											
					 end	
				end
		   end   
		
		
		  
		4'h2:                                         //minute set 
		   begin
			if(timmer == 1)
   		 setcb = 0;
	     else
			 begin
			   if(adj == 1 & cf == 0) 
			                                              
			       begin
			           
	                       if(mcb[7:4]==4'h5)                            
	                         begin
	                           if(mcb[3:0]== 4'h9)
							          begin
										 mcb = 0;
		                         end
							         else
							         mcb[3:0]=mcb[3:0]+1;
					                            
			                   end    			        
		                   else  
                           begin
		                     if(mcb[3:0] == 4'h9)
							         begin
							      mcb[3:0] =0;
							      mcb[7:4] = mcb[7:4]+1;
					               end
                           else							
					            mcb[3:0]=mcb[3:0]+1;
                           end 
		             transfer = 2'b10;	
				          
				      end

            else if(adj == 0 & cf == 1)                          
                begin
					      if(mcb[7:4]==4'h0)                            
	                         begin
	                           if(mcb[3:0]== 4'h0)
							          begin
										 mcb[7:4] = 5;
		                        mcb[3:0] = 9;
										 end
							         else
							         mcb[3:0]=mcb[3:0] - 1;
					                            
			                   end    			        
		                   else  
                           begin
		                     if(mcb[3:0] == 0)
							         begin
							      mcb[3:0] =9;
							      mcb[7:4] = mcb[7:4] - 1;
					               end
                           else							
					            mcb[3:0]=mcb[3:0] - 1;
                           end 	
                    transfer = 2'b10;	 									
					 end	
				end	
		   end   
		
		
		
		4'h3:                                       //second  set
		
		    begin
			 if(timmer == 1)
   		 setcb = 0;
	     else
			 begin
			    if(adj == 1 & cf == 0) 
			                                           
			       begin
			           
	                       if(scb[7:4]==4'h5)                            
	                         begin
	                           if(scb[3:0]== 4'h9)
							          begin
										 scb = 0;
		                         end
							         else
							         scb[3:0]=scb[3:0]+1;
					                            
			                   end    			        
		                   else  
                           begin
		                     if(scb[3:0] == 4'h9)
							         begin
							      scb[3:0] =0;
							      scb[7:4] = scb[7:4]+1;
					               end
                           else							
					            scb[3:0]=scb[3:0]+1;
                           end 
		             
				          transfer = 2'b11		;
				      end

            else if(adj ==0 & cf==1)                          
                begin
					      if(scb[7:4]==4'h0)                            
	                         begin
	                           if(scb[3:0]== 4'h0)
							          begin
										 scb[7:4] = 4'h5;
		                         scb[3:0] = 4'h9;
										 end
							         else
							         scb[3:0]=scb[3:0] - 1;
					                            
			                   end    			        
		                 else  
                           begin
		                     if(scb[3:0] == 0)
							         begin
							      scb[3:0] =9;
							      scb[7:4] = scb[7:4] - 1;
					               end
                           else							
					            scb[3:0]=scb[3:0] - 1;
                           end 	
                     transfer = 2'b11		;									
					 end	
				end
		   end   
		
		
		
		default:                             //out of set , back time  going 		          
		  begin   
		  transfer = 2'b00	 ;  
        setcb = 000;
		  end
		
    endcase
			  
	
   end
	
         
	 
	  
	     


end
end

*/


//---------------------set=000,timmer=1-----time stop  -----------------------------------
//--------------------- if this time ,we give ADJ=1 , give hour , minute ,second =0-----------------
//---------------------------set=000 and timmer=1,time  begin-------------going back clock



always @(posedge clk)
begin
if(transfer == 2'b11)
 
		   sback =  scb  ;

else
begin
  cls = 0;
  begin
 if(setcb ==000 & modestate == 2'b10 )
    if(timmergo == 0)
	     begin
		  if (adj == 1)		
			sback = 0;
	    		
		 end 
 
  else if(setcb ==0 & modestate == 2'b10  )
       if(timmergo == 1)
	     begin
			if(transfer == 2'b11)
  		    sback = scb;
			 else
			 			 
				    begin                           // second go
					 if(sback[7:4]==0)                            
	                begin						 
	                if(sback[3:0]== 0)
						 begin
						   
						     begin
							  if(mback>0 | hback>0)
                        begin
								sback[7:4] = 5 ;
                        sback[3:0] = 9 ;
                        cls = 1 ;								
                       end
                        								
						      end
								
							end	
						  else						  
						  sback[3:0]=sback[3:0] - 1;					                            
			           end  
                   							  
		          else  
                    begin
		              if(sback[3:0] == 0)
							begin
							sback[3:0] =9;
							sback[7:4] = sback[7:4] - 1;							
					      end
                     else							
					      sback[3:0]=sback[3:0] - 1;
                    end 			 
							 
							 
					 end
	 end
	end
  
end
end


always @(posedge clk  )                              //minute go
begin
if(transfer == 2'b10)
 		  mback   =  mcb ;
		   
else


begin
 clh=0;

begin 
 if(setcb ==000 & modestate == 2'b10 )
     if(timmergo == 0)
	     begin
		  if (adj == 1)		
			 mback = 0;
	    		
		  end 




 else if(setcb ==0 & modestate == 2'b10  )
    if(cls ==1)
     if(timmergo == 1)
      begin
       if(transfer == 2'b10)
  		    mback = mcb;
	 
					      if(mback[7:4]==4'h0)                            
	                         begin
	                           if(mback[3:0]== 4'h0)
							          begin
										   
										   if(hback>0)
										    begin
										    mback[7:4] = 5;
		                            mback[3:0] = 9;
											 clh = 1;
										    end
										 								 
										 end
							         else
							         mback[3:0]=mback[3:0] - 1;
					                            
			                   end    			        
		                   else  
                           begin
		                     if(mback[3:0] == 0)
							         begin
							      mback[3:0] =9;
							      mback[7:4] = mback[7:4] - 1;
					               end
                           else							
					            mback[3:0]=mback[3:0] - 1;
                           end 			
	end   
  end
 end 
end	


always @(posedge clk )
begin
if(transfer == 2'b01)
 hback =  hcb  ;
else


begin
  if(setcb ==000 & modestate == 2'b10 )          //hour  go
  if(timmergo == 0)
	   begin
		if (adj == 1)		
			hback = 0;
	    		
		end 





  else if(setcb ==0 & modestate == 2'b10  )
    if(timmergo == 1)
	  if(clh == 1)
      begin
      if(transfer == 2'b01)
  		    hback = hcb;
		 else
					      if(hback[7:4]==4'b0000)                            
	                         begin
	                           if(hback[3:0]== 4'b0000)
							          begin
										 hback =0 ;
										 end
							         else
							         hback[3:0]=hback[3:0] - 1;
					                            
			                   end    			        
		                   else  
                           begin
		                     if(hback[3:0] == 0)
							         begin
							      hback[3:0] =9;
							      hback[7:4] = hback[7:4] - 1;
					               end
                           else							
					            hback[3:0]=hback[3:0] - 1;
                           end 	
  								
	end   
end		     
	
end	
	
	
endmodule