1 files changed, 76 insertions, 0 deletions
diff --git a/fpga/usrp2/control_lib/sd_spi_wb.v b/fpga/usrp2/control_lib/sd_spi_wb.v
new file mode 100644
index 000000000..7a6258b56
--- /dev/null
+++ b/fpga/usrp2/control_lib/sd_spi_wb.v
@@ -0,0 +1,76 @@
+
+// Wishbone module for spi communications with an SD Card
+// The programming interface is simple -- 
+//      Write the desired clock divider to address 1 (should be 1 or higher)
+//      Status is in address 0.  A 1 indicates the last transaction is done and it is safe to
+//          send another
+//      Writing a byte to address 2 sends that byte over SPI.  When it is done, 
+//          status (addr 0) goes high again, and the received byte can be read from address 3.
+
+module sd_spi_wb
+  (input clk,
+   input rst,
+   
+   // SD Card interface
+   output sd_clk,
+   output sd_csn,
+   output sd_mosi,
+   input sd_miso,
+
+   input wb_cyc_i,
+   input wb_stb_i,
+   input wb_we_i,
+   input [1:0] wb_adr_i,
+   input [7:0] wb_dat_i,
+   output reg [7:0] wb_dat_o,
+   output reg wb_ack_o);
+
+   localparam ADDR_STATUS = 0;
+   localparam ADDR_CLKDIV = 1;
+   localparam ADDR_WRITE = 2;
+   localparam ADDR_READ = 3;
+
+   wire [7:0] status, rcv_dat;
+   reg [7:0]  clkdiv;
+   wire       ready;
+   reg 	      ack_d1;
+
+   reg 	      cs_reg;
+   assign     sd_csn = ~cs_reg;  // FIXME
+   
+   always @(posedge clk)
+     if(rst) ack_d1 <= 0;
+     else ack_d1 <= wb_ack_o;
+   
+   always @(posedge clk)
+     if(rst) wb_ack_o <= 0;
+     else wb_ack_o <= wb_cyc_i & wb_stb_i & ~ack_d1;
+   
+   always @(posedge clk)
+     case(wb_adr_i)
+       ADDR_STATUS : wb_dat_o <= {7'd0,ready};
+       ADDR_CLKDIV : wb_dat_o <= clkdiv;
+       ADDR_READ : wb_dat_o <= rcv_dat;
+       default : wb_dat_o <= 0;
+     endcase // case(wb_adr_i)
+
+   always @(posedge clk)
+     if(rst)
+       begin
+	  clkdiv <= 200;
+	  cs_reg <= 0;
+       end
+     else if(wb_we_i & wb_stb_i & wb_cyc_i & wb_ack_o)
+       case(wb_adr_i)
+	 ADDR_STATUS : cs_reg <= wb_dat_i;
+	 ADDR_CLKDIV : clkdiv <= wb_dat_i;
+       endcase // case(wb_adr_i)
+
+   wire       go = wb_we_i & wb_stb_i & wb_cyc_i & wb_ack_o & (wb_adr_i == ADDR_WRITE);
+   
+   sd_spi sd_spi(.clk(clk),.rst(rst),
+		 .sd_clk(sd_clk),.sd_mosi(sd_mosi),.sd_miso(sd_miso),
+		 .clk_div(clkdiv),.send_dat(wb_dat_i),.rcv_dat(rcv_dat),
+		 .go(go),.ready(ready) );
+
+endmodule // sd_spi_wb