Merged r9433:9527 from features/gr-usrp2 into trunk. Adds usrp2 and gr-usrp2 top-level components. Trunk passes distcheck with mb-gcc installed, but currently not without them. The key issue is that when mb-gcc is not installed, the build system skips over the usrp2/firmware directory, and the firmware include files don't get put into the dist tarball. But we can't do the usual DIST_SUBDIRS method as the firmware is a subpackage.

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@9528 221aa14e-8319-0410-a670-987f0aec2ac5

1 files changed, 29 insertions, 0 deletions

diff --git a/usrp2/fpga/control_lib/gray_send.v b/usrp2/fpga/control_lib/gray_send.v
new file mode 100644
index 000000000..7fc07d40c
--- /dev/null
+++ b/usrp2/fpga/control_lib/gray_send.v
@@ -0,0 +1,29 @@
+
+
+
+module gray_send
+  #(parameter WIDTH = 8)
+    (input clk_in, input [WIDTH-1:0] addr_in,
+     input clk_out, output reg [WIDTH-1:0] addr_out);
+
+   reg [WIDTH-1:0] gray_clkin, gray_clkout, gray_clkout_d1;
+   wire [WIDTH-1:0] gray, bin;
+
+   bin2gray #(.WIDTH(WIDTH)) b2g (.bin(addr_in), .gray(gray) );
+
+   always @(posedge clk_in)
+     gray_clkin <= gray;
+
+   always @(posedge clk_out)
+     gray_clkout <= gray_clkin;
+
+   always @(posedge clk_out)
+     gray_clkout_d1 <= gray_clkout;
+   
+   gray2bin #(.WIDTH(WIDTH)) g2b (.gray(gray_clkout_d1), .bin(bin) );
+
+   // FIXME we may not need the next register, but it may help timing
+   always @(posedge clk_out)
+     addr_out <= bin;
+   
+endmodule // gray_send