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-rw-r--r--fpga/usrp3/lib/control/settings_bus_crossclock.v26
1 files changed, 26 insertions, 0 deletions
diff --git a/fpga/usrp3/lib/control/settings_bus_crossclock.v b/fpga/usrp3/lib/control/settings_bus_crossclock.v
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+++ b/fpga/usrp3/lib/control/settings_bus_crossclock.v
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+//
+// Copyright 2011-2012 Ettus Research LLC
+//
+
+
+
+
+// This module takes the settings bus on one clock domain and crosses it over to another domain
+// Typically it will be used with the input settings bus on the wishbone clock, and either
+// the system or dsp clock on the output side
+
+module settings_bus_crossclock
+ #(parameter FLOW_CTRL=0, parameter AWIDTH=8, parameter DWIDTH=32)
+ (input clk_i, input rst_i, input set_stb_i, input [AWIDTH-1:0] set_addr_i, input [DWIDTH-1:0] set_data_i,
+ input clk_o, input rst_o, output set_stb_o, output [AWIDTH-1:0] set_addr_o, output [DWIDTH-1:0] set_data_o, input blocked);
+
+ wire nfull, nempty;
+
+ axi_fifo_2clk #(.WIDTH(AWIDTH + DWIDTH), .SIZE(0)) settings_fifo
+ (.reset(rst_i),
+ .i_aclk(clk_i), .i_tdata({set_addr_i,set_data_i}), .i_tvalid(set_stb_i), .i_tready(nfull),
+ .o_aclk(clk_o), .o_tdata({set_addr_o,set_data_o}), .o_tready(set_stb_o), .o_tvalid(nempty));
+
+ assign set_stb_o = nempty & (~blocked | ~FLOW_CTRL);
+
+endmodule // settings_bus_crossclock