diff --git a/rtl/apple1_mist.sv b/rtl/apple1_mist.sv
index cfa34a5..6bc724a 100644
--- a/rtl/apple1_mist.sv
+++ b/rtl/apple1_mist.sv
@@ -552,7 +552,7 @@ clock clock(
   .reset      ( reset_button  ),   // input: reset signal
 
   .cpu_clock  ( cpu_clock     ),  
-  .cpu_clken  ( cpu_clken     ),   // output: cpu clock enable
+  .cpu_clken  ( cpu_clken     ),   // output: cpu clock enable (phi2)
   .pixel_clken( pixel_clken   )    // output: pixel clock enable
 );
 
diff --git a/rtl/clock.v b/rtl/clock.v
index 4356c20..6142092 100644
--- a/rtl/clock.v
+++ b/rtl/clock.v
@@ -10,30 +10,36 @@ module clock
 	output cpu_clock
 );
 
-localparam CPU_DIVISOR   = 56;  // (sys_clock / CPU_DIVISOR)   = 1 MHz
-localparam PIXEL_DIVISOR = 8;   // (sys_clock / PIXEL_DIVISOR) = 7 MHz
+localparam CPU_DIVISOR     = 56;  // (sys_clock / CPU_DIVISOR)   = 1 MHz
+localparam PIXEL_DIVISOR   =  8;  // (sys_clock / PIXEL_DIVISOR) = 7 MHz
+localparam REFRESH_DIVISOR = 65;  // 
 
 	reg [5:0] counter_cpu;
 	reg [2:0] counter_pixel;
+	reg [7:0] counter_refresh;
 	
 	always @(posedge sys_clock or posedge reset)
 	begin
 	   if(reset) begin
-			counter_cpu   <= 0;
-			counter_pixel <= 0;
+			counter_cpu     <= 0;
+			counter_pixel   <= 0;
+			counter_refresh <= 0;
 		end
 		else begin			
 		   
-			if (counter_cpu == (CPU_DIVISOR-1)) counter_cpu <= 0;
-			else                                counter_cpu <= counter_cpu + 1;
+			if (counter_cpu == (CPU_DIVISOR-1)) begin
+				counter_cpu <= 0;
+				counter_refresh <= (counter_refresh == REFRESH_DIVISOR-1) ? 0 : counter_refresh + 1;  				
+			end 
+			else 
+			   counter_cpu <= counter_cpu + 1;
 
-			if (counter_pixel == (PIXEL_DIVISOR-1)) counter_pixel <= 0;
-			else                                    counter_pixel <= counter_pixel + 1;
+			counter_pixel <= (counter_pixel == PIXEL_DIVISOR-1) ? 0 : counter_pixel + 1;
 						
 		end
 	end
 	
-	assign cpu_clken   = counter_cpu   == 0;
+	assign cpu_clken   = counter_cpu   == 0 /*&& counter_refresh > 3*/;
 	assign pixel_clken = counter_pixel == 0;
 	
 	assign cpu_clock = counter_pixel < 4 ? 1 : 0;