Pattern is being detected in any bit position now

Author: pConst

pattern_detect.sv

@@ -5,53 +5,80 @@
 //------------------------------------------------------------------------------
 
 // INFO ------------------------------------------------------------------------
-// Detects data pattern specified by the provided PATTERN
+// Detects data pattern specified by the provided PAT parameter
 //
 // Features capturing WIDTH bits simultaneously in case your data
-// comes in parallel, like in QSPI interface, for example.
+// comes in parallel, like in QSPI interface, for example
+//
+// Detects pattern in any possible bit position, supposing that input data
+// is an unaligned bit stream
 //
 
 /* --- INSTANTIATION TEMPLATE BEGIN ---
 
 pattern_detect #(
   .DEPTH( 2 ),
-  .WIDTH( 5 ),
-  .PATTERN( 10'b11111_10011 )
+  .WIDTH( 16 ),
+
+  // pattern parameters
+  .PAT_WIDTH( 5 ),           // must be less than DEPTH*WIDTH
+  .PAT( 5'b10011 )
 ) PD1 (
   .clk( clk ),
   .nrst( nrst ),
   .ena( 1'b1 ),
   .data( data[4:0] ),
+
+  .detected_pos(  )
   .detected(  )
 );
 
 --- INSTANTIATION TEMPLATE END ---*/
 
 
 module pattern_detect #( parameter
-  DEPTH = 1,
-  WIDTH = 1,
-  logic [DEPTH*WIDTH-1:0] PATTERN = '0
+  DEPTH = 2,
+  WIDTH = 16,
+
+  PAT_WIDTH = 5,          // must be less than DEPTH*WIDTH
+  bit [PAT_WIDTH-1:0] PAT = '1
 )(
   input clk,
   input nrst,
 
   input ena,
   input [WIDTH-1:0] data,
 
-  output detected
+  output logic detected,
+  output logic [DEPTH*WIDTH-1:0] detected_mask
 );
 
-  logic [DEPTH*WIDTH-1:0] samples = '0;
+  logic [DEPTH*WIDTH-1:0] sample_buf = '0;
+  logic [DEPTH*WIDTH-1:0] ena_buf = '0;
   always @ (posedge clk) begin
     if( ~nrst ) begin
-      samples[DEPTH*WIDTH-1:0] <= '0;
-    end else if( ena ) begin
-      samples[DEPTH*WIDTH-1:0] <= {samples[DEPTH*WIDTH-WIDTH-1:0],data[WIDTH-1:0]};
+      sample_buf[DEPTH*WIDTH-1:0] <= {DEPTH*WIDTH{1'b0}};
+      ena_buf[DEPTH*WIDTH-1:0] <= {DEPTH*WIDTH{1'b0}};
+    end else begin
+      sample_buf[DEPTH*WIDTH-1:0] <= {sample_buf[DEPTH*WIDTH-WIDTH-1:0],
+                                      data[WIDTH-1:0]};
+      ena_buf[DEPTH*WIDTH-1:0] <= {ena_buf[DEPTH*WIDTH-WIDTH-1:0],
+                                  {WIDTH{ena}} };
     end
   end
 
-  assign detected = (samples[DEPTH*WIDTH-1:0] == PATTERN[DEPTH*WIDTH-1:0]);
+  always_comb begin
+    integer i;
+
+    detected_mask[DEPTH*WIDTH-1:0] = '0;
+    for( i=0; i<(DEPTH*WIDTH-PAT_WIDTH); i++ ) begin
+      if( sample_buf[i+:PAT_WIDTH] == PAT[PAT_WIDTH-1:0] &&
+          ena_buf[i+:PAT_WIDTH]) begin
+        detected_mask[i] = 1'b1;
+      end
+    end
+    detected = |detected_mask[DEPTH*WIDTH-1:0];
+  end
 
 endmodule
 

pattern_detect_tb.sv

@@ -103,16 +103,22 @@ end
 // Module under test ===========================================================
 
 logic [15:0] detected;
+logic [15:0][9:0] detected_mask;
+
 pattern_detect #(
   .DEPTH( 5 ),
   .WIDTH( 2 ),
-  .PATTERN( 10'b10_01_11_00_11 )
+
+  .PAT_WIDTH( 7 ),
+  .PAT( 7'b1_11_00_11 )
 ) pd [15:0] (
   .clk( {16{clk200}} ),
   .nrst( {16{nrst_once}} ),
   .ena( '1 ),
   .data( rnd_data[31:0] ),
-  .detected( detected[15:0] )
+
+  .detected( detected[15:0] ),
+  .detected_mask( detected_mask )
 );