1 files changed, 82 insertions, 0 deletions
diff --git a/fpga/usrp1/models/fifo.v b/fpga/usrp1/models/fifo.v
new file mode 100644
index 000000000..0ade49e9c
--- /dev/null
+++ b/fpga/usrp1/models/fifo.v
@@ -0,0 +1,82 @@
+// Model of FIFO in Altera
+
+module fifo( data, wrreq, rdreq, rdclk, wrclk, aclr, q,
+		    rdfull, rdempty, rdusedw, wrfull, wrempty, wrusedw);
+   
+   parameter width = 16;
+   parameter depth = 1024;
+   parameter addr_bits = 10;
+   
+   //`define rd_req 0;  // Set this to 0 for rd_ack, 1 for rd_req
+   
+   input [width-1:0] data;
+   input 	     wrreq;
+   input 	     rdreq;
+   input 	     rdclk;
+   input 	     wrclk;
+   input 	     aclr;
+   output [width-1:0] q;
+   output 	      rdfull;
+   output 	      rdempty;
+   output reg [addr_bits-1:0]  rdusedw;
+   output wrfull;
+   output wrempty;
+   output reg [addr_bits-1:0]  wrusedw;
+   
+   reg [width-1:0] mem [0:depth-1];
+   reg [addr_bits-1:0] 	      rdptr;
+   reg [addr_bits-1:0] 	      wrptr;
+   
+`ifdef rd_req
+   reg [width-1:0]    q;
+`else
+   wire [width-1:0]   q;
+`endif
+   
+   integer 	      i;
+   
+   always @( aclr)
+     begin
+	wrptr <= #1 0;
+	rdptr <= #1 0;
+	for(i=0;i<depth;i=i+1)
+	  mem[i] <= #1 0;
+     end
+   
+   always @(posedge wrclk)
+     if(wrreq)
+       begin
+	  wrptr <= #1 wrptr+1;
+	  mem[wrptr] <= #1 data;
+       end
+   
+   always @(posedge rdclk)
+     if(rdreq)
+       begin
+   	  rdptr <= #1 rdptr+1;
+`ifdef rd_req
+	  q <= #1 mem[rdptr];
+`endif
+       end
+   
+`ifdef rd_req
+`else
+   assign q = mem[rdptr];
+`endif
+   
+   // Fix these
+   always @(posedge wrclk)
+     wrusedw <= #1 wrptr - rdptr;
+   
+   always @(posedge rdclk)
+     rdusedw <= #1 wrptr - rdptr;
+   
+   assign wrempty = (wrusedw == 0);
+   assign wrfull = (wrusedw == depth-1);
+   
+   assign rdempty = (rdusedw == 0);
+   assign rdfull = (rdusedw == depth-1);
+   
+endmodule // fifo
+
+