initial import

1 files changed, 33 insertions, 0 deletions

diff --git a/tests/asicworld/code_hdl_models_GrayCounter.v b/tests/asicworld/code_hdl_models_GrayCounter.v
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+++ b/tests/asicworld/code_hdl_models_GrayCounter.v
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+//==========================================
+// Function : Code Gray counter.
+// Coder    : Alex Claros F.
+// Date     : 15/May/2005.
+//=======================================
+
+module GrayCounter
+   #(parameter   COUNTER_WIDTH = 4)
+   
+    (output reg  [COUNTER_WIDTH-1:0]    GrayCount_out,  //'Gray' code count output.
+    
+     input wire                         Enable_in,  //Count enable.
+     input wire                         Clear_in,   //Count reset.
+    
+     input wire                         Clk);
+
+    /////////Internal connections & variables///////
+    reg    [COUNTER_WIDTH-1:0]         BinaryCount;
+
+    /////////Code///////////////////////
+    
+    always @ (posedge Clk)
+        if (Clear_in) begin
+            BinaryCount   <= {COUNTER_WIDTH{1'b 0}} + 1;  //Gray count begins @ '1' with
+            GrayCount_out <= {COUNTER_WIDTH{1'b 0}};      // first 'Enable_in'.
+        end
+        else if (Enable_in) begin
+            BinaryCount   <= BinaryCount + 1;
+            GrayCount_out <= {BinaryCount[COUNTER_WIDTH-1],
+                              BinaryCount[COUNTER_WIDTH-2:0] ^ BinaryCount[COUNTER_WIDTH-1:1]};
+        end
+    
+endmodule