first cut

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@9609 221aa14e-8319-0410-a670-987f0aec2ac5

1 files changed, 146 insertions, 0 deletions

diff --git a/extram/extram_wb.v b/extram/extram_wb.v
new file mode 100644
index 000000000..8142047d7
--- /dev/null
+++ b/extram/extram_wb.v
@@ -0,0 +1,146 @@
+
+module extram_wb
+  #(parameter PAGE_SIZE = 10,
+    parameter ADDR_WIDTH = 16)
+    (input clk, input rst,
+     input wb_clk, input wb_rst,
+     input cyc_i, input stb_i,
+     input [ADDR_WIDTH-1:0] adr_i,
+     input we_i,
+     input [31:0] dat_i,
+     output reg [31:0] dat_o,
+     output reg ack_o,
+     
+     inout [17:0] RAM_D,
+     output [PAGE_SIZE-2:0] RAM_A,
+     output RAM_CE1n, output RAM_CENn,
+     output RAM_CLK, output RAM_WEn,
+     output RAM_OEn, output RAM_LDn );
+
+   wire     read_acc = stb_i & cyc_i & ~we_i;
+   wire     write_acc = stb_i & cyc_i & we_i;
+   wire     acc = stb_i & cyc_i;
+
+   assign   RAM_CLK = wb_clk;   // 50 MHz for now, eventually should be 200 MHz
+   assign   RAM_LDn = 0;        // No burst for now
+   assign   RAM_CENn = 0;       // Use CE1n as our main CE
+
+   reg [PAGE_SIZE-2:1] RAM_addr_reg;
+   always @(posedge wb_clk)
+     if(acc)
+       RAM_addr_reg[PAGE_SIZE-2:1] <= adr_i[PAGE_SIZE-1:2];
+   assign 	       RAM_A[PAGE_SIZE-2:1] = RAM_addr_reg; 
+
+   reg [31:0] 	       ram_out;
+   always @(posedge wb_clk)
+     if(write_acc)
+       ram_out <= dat_i;
+
+   // RAM access state machine
+   localparam RAM_idle = 0;
+   localparam RAM_read_1 = 1;
+   localparam RAM_read_2 = 2;
+   localparam RAM_read_3 = 3;
+   localparam RAM_read_4 = 4;
+   localparam RAM_write_1 = 6;
+   localparam RAM_write_2 = 7;
+   localparam RAM_write_3 = 8;
+   localparam RAM_write_4 = 9;
+
+   reg 	      myOE = 0;
+   reg 	      RAM_OE = 0;
+   reg 	      RAM_WE = 0;
+   reg 	      RAM_EN = 0;
+   reg 	      RAM_A0_reg;
+   reg [3:0]  RAM_state;
+   
+   always @(posedge wb_clk)
+     if(wb_rst)
+       begin
+	  RAM_state <= RAM_idle;
+	  myOE <= 0; RAM_OE <= 0; RAM_WE <= 0; RAM_EN <= 0; RAM_A0_reg <= 0;
+       end
+     else
+       case(RAM_state)
+	 RAM_idle :
+	   if(read_acc)
+	     begin
+		RAM_state <= RAM_read_1;
+		myOE <= 0; RAM_OE <= 0; RAM_WE <= 0; RAM_EN <= 1; RAM_A0_reg <= 0;
+	     end
+	   else if(write_acc)
+	     begin
+		RAM_state <= RAM_write_1;
+		myOE <= 0; RAM_OE <= 0; RAM_WE <= 1; RAM_EN <= 1; RAM_A0_reg <= 0;
+	     end
+	   else
+	     begin
+		myOE <= 0; RAM_OE <= 0; RAM_WE <= 0; RAM_EN <= 0; RAM_A0_reg <= 0;
+	     end
+	 RAM_read_1 : 
+	   begin
+	      RAM_state <= RAM_read_2;
+	      myOE <= 0; RAM_OE <= 0; RAM_WE <= 0; RAM_EN <= 1; RAM_A0_reg <= 1;
+	   end
+	 RAM_read_2 : 
+	   begin
+	      RAM_state <= RAM_read_3;
+	      myOE <= 0; RAM_OE <= 1; RAM_WE <= 0; RAM_EN <= 0; RAM_A0_reg <= 0;
+	   end
+	 RAM_read_3 : 
+	   begin
+	      RAM_state <= RAM_read_4;
+	      myOE <= 0; RAM_OE <= 1; RAM_WE <= 0; RAM_EN <= 0; RAM_A0_reg <= 0;
+	   end
+	 RAM_read_4 :
+	   begin
+	      RAM_state <= RAM_idle;
+	      myOE <= 0; RAM_OE <= 0; RAM_WE <= 0; RAM_EN <= 0; RAM_A0_reg <= 0;
+	   end
+	 RAM_write_1 : 
+	   begin
+	      RAM_state <= RAM_write_2;
+	      myOE <= 0; RAM_OE <= 0; RAM_WE <= 1; RAM_EN <= 1; RAM_A0_reg <= 1;
+	   end
+	 RAM_write_2 : 
+	   begin
+	      RAM_state <= RAM_write_3;
+	      myOE <= 1; RAM_OE <= 0; RAM_WE <= 0; RAM_EN <= 0; RAM_A0_reg <= 0;
+	   end
+	 RAM_write_3 : 
+	   begin
+	      RAM_state <= RAM_write_4;
+	      myOE <= 1; RAM_OE <= 0; RAM_WE <= 0; RAM_EN <= 0; RAM_A0_reg <= 0;
+	   end
+	 RAM_write_4 : 
+	   begin
+	      RAM_state <= RAM_idle;
+	      myOE <= 0; RAM_OE <= 0; RAM_WE <= 0; RAM_EN <= 0; RAM_A0_reg <= 0;
+	   end
+	 default : RAM_state <= RAM_idle;
+       endcase // case(RAM_state)
+   
+   assign     RAM_A[0] = RAM_A0_reg;
+   assign     RAM_WEn = ~RAM_WE;  // ((RAM_state==RAM_write_1)||(RAM_state==RAM_write_2));
+   assign     RAM_OEn = ~RAM_OE;
+   assign     RAM_CE1n = ~RAM_EN;    // Active low     (RAM_state != RAM_idle);
+   
+   assign     RAM_D[17:16] = 2'bzz;
+   assign     RAM_D[15:0] = myOE ? ((RAM_state==RAM_write_3)?ram_out[15:0]:ram_out[31:16]) 
+	      : 16'bzzzz_zzzz_zzzz_zzzz;
+
+   always @(posedge wb_clk)
+     if(RAM_state == RAM_read_3)
+       dat_o[15:0] <= RAM_D[15:0];
+     else
+       dat_o[31:16] <= RAM_D[15:0];
+   
+   always @(posedge wb_clk)
+     if(wb_rst)
+       ack_o <= 0;
+     else if((RAM_state == RAM_write_4)||(RAM_state == RAM_read_4))
+       ack_o <= 1;
+     else
+       ack_o <= 0;
+   
+endmodule // extram_wb