Merge remote branch 'origin/usrp_e_next' into usrp_e_next

17 files changed, 753 insertions, 0 deletions

diff --git a/fpga/usrp2/gpmc/.gitignore b/fpga/usrp2/gpmc/.gitignore
new file mode 100644
index 000000000..3e14fa4f7
--- /dev/null
+++ b/fpga/usrp2/gpmc/.gitignore
@@ -0,0 +1,2 @@
+*.gif
+
diff --git a/fpga/usrp2/gpmc/Makefile.srcs b/fpga/usrp2/gpmc/Makefile.srcs
new file mode 100644
index 000000000..bff6ae3e0
--- /dev/null
+++ b/fpga/usrp2/gpmc/Makefile.srcs
@@ -0,0 +1,20 @@
+#
+# Copyright 2010 Ettus Research LLC
+#
+
+##################################################
+# SERDES Sources
+##################################################
+GPMC_SRCS = $(abspath $(addprefix $(BASE_DIR)/../gpmc/, \
+dbsm.v \
+edge_sync.v \
+fifo_to_gpmc_async.v \
+fifo_to_gpmc_sync.v \
+fifo_watcher.v \
+gpmc_async.v \
+gpmc_sync.v \
+gpmc_to_fifo_async.v \
+gpmc_to_fifo_sync.v \
+gpmc_wb.v \
+ram_to_fifo.v \
+))
diff --git a/fpga/usrp2/gpmc/burst_data_write.txt b/fpga/usrp2/gpmc/burst_data_write.txt
new file mode 100644
index 000000000..3b5dfc785
--- /dev/null
+++ b/fpga/usrp2/gpmc/burst_data_write.txt
@@ -0,0 +1,16 @@
+# OMAP burst writes to FPGA
+
+CLK=0,nWE=1,nCS=1,nOE=1,DATA=Z.
+CLK=1.
+CLK=0,nWE=0,nCS=0,DATA=WR_DATA1.
+CLK=1.
+CLK=0,nWE=0,nCS=0,DATA=WR_DATA2.
+CLK=1.
+CLK=0,nWE=0,nCS=0,DATA=WR_DATA3.
+CLK=1.
+CLK=0,nWE=0,nCS=0,DATA=WR_DATA4.
+CLK=1.
+CLK=0,nWE=1,nCS=1,DATA=Z.
+CLK=1.
+
+
diff --git a/fpga/usrp2/gpmc/dbsm.v b/fpga/usrp2/gpmc/dbsm.v
new file mode 100644
index 000000000..530af7205
--- /dev/null
+++ b/fpga/usrp2/gpmc/dbsm.v
@@ -0,0 +1,80 @@
+
+module bsm
+  (input clk, input reset, input clear,
+   input write_done,
+   input read_done,
+   output readable,
+   output writeable);
+
+   reg 	  state;
+   localparam ST_WRITEABLE = 0;
+   localparam ST_READABLE = 1;
+   
+   always @(posedge clk)
+     if(reset | clear)
+       state <= ST_WRITEABLE;
+     else
+       case(state)
+	 ST_WRITEABLE :
+	   if(write_done)
+	     state <= ST_READABLE;
+	 ST_READABLE :
+	   if(read_done)
+	     state <= ST_WRITEABLE;
+       endcase // case (state)
+
+   assign readable = (state == ST_READABLE);
+   assign writeable = (state == ST_WRITEABLE);
+   
+endmodule // bsm
+
+module dbsm
+  (input clk, input reset, input clear,
+   output reg read_sel, output read_ready, input read_done,
+   output reg write_sel, output write_ready, input write_done);
+
+   localparam NUM_BUFS = 2;
+
+   wire       [NUM_BUFS-1:0] readable, writeable, read_done_buf, write_done_buf;
+   
+   // Two of these buffer state machines
+   genvar     i;
+   generate
+      for(i=0;i<NUM_BUFS;i=i+1)
+	begin : BSMS
+	   bsm bsm(.clk(clk), .reset(reset), .clear(clear),
+		   .write_done((write_sel == i) & write_done),
+		   .read_done((read_sel == i) & read_done),
+		   .readable(readable[i]), .writeable(writeable[i]));
+	end
+   endgenerate
+   
+   reg 	 full;
+   
+   always @(posedge clk)
+     if(reset | clear)
+       begin
+	  write_sel <= 0;
+	  full <= 0;
+       end
+     else
+       if(write_done & writeable[write_sel])
+	 if(write_sel ==(NUM_BUFS-1))
+	   write_sel <= 0;
+	 else
+	   write_sel <= write_sel + 1;
+   
+   always @(posedge clk)
+     if(reset | clear)
+       read_sel <= 0;
+     else
+       if(read_done & readable[read_sel])
+	 if(read_sel==(NUM_BUFS-1))
+	   read_sel <= 0;
+	 else
+	   read_sel <= read_sel + 1;
+          
+   assign write_ready = writeable[write_sel];
+   assign read_ready = readable[read_sel];
+
+endmodule // dbsm
diff --git a/fpga/usrp2/gpmc/edge_sync.v b/fpga/usrp2/gpmc/edge_sync.v
new file mode 100644
index 000000000..5d9417c08
--- /dev/null
+++ b/fpga/usrp2/gpmc/edge_sync.v
@@ -0,0 +1,22 @@
+
+
+module edge_sync
+  #(parameter POSEDGE = 1)
+   (input clk,
+    input rst,
+    input sig,
+    output trig);
+   
+   reg [1:0] delay;
+   
+   always @(posedge clk)
+     if(rst)
+       delay <= 2'b00;
+     else
+       delay <= {delay[0],sig};
+   
+   assign trig = POSEDGE ? (delay==2'b01) : (delay==2'b10);
+   
+endmodule // edge_sync
+
+
diff --git a/fpga/usrp2/gpmc/fifo_to_gpmc_async.v b/fpga/usrp2/gpmc/fifo_to_gpmc_async.v
new file mode 100644
index 000000000..cf8b6e861
--- /dev/null
+++ b/fpga/usrp2/gpmc/fifo_to_gpmc_async.v
@@ -0,0 +1,37 @@
+
+// Assumes an asynchronous GPMC cycle
+//   If a packet bigger or smaller than we are told is sent, behavior is undefined.
+//   If dst_rdy_i is low when we get data, behavior is undefined and we signal bus error.
+//   If there is a bus error, we should be reset
+
+module fifo_to_gpmc_async
+  (input clk, input reset, input clear,
+   input [17:0] data_i, input src_rdy_i, output dst_rdy_o,
+   output [15:0] EM_D, input EM_NCS, input EM_NOE,
+   input [15:0] frame_len);
+
+   // Synchronize the async control signals
+   reg [2:0] 	cs_del, oe_del;
+   reg [15:0] 	counter;
+   
+   always @(posedge clk)
+     if(reset)
+       begin
+	  cs_del <= 3'b11;
+	  oe_del <= 3'b11;
+       end
+     else
+       begin
+	  cs_del <= { cs_del[1:0], EM_NCS };
+	  oe_del <= { oe_del[1:0], EM_NOE };
+       end
+
+   wire do_read = ( (~cs_del[1] | ~cs_del[2]) & (oe_del[1:0] == 2'b01));  // change output on trailing edge
+   wire first_read = (counter == 0);
+   wire last_read = ((counter+1) == frame_len);
+
+   assign EM_D = data_i[15:0];
+
+   assign dst_rdy_o = do_read;
+
+endmodule // fifo_to_gpmc_async
diff --git a/fpga/usrp2/gpmc/fifo_to_gpmc_sync.v b/fpga/usrp2/gpmc/fifo_to_gpmc_sync.v
new file mode 100644
index 000000000..ef59d7137
--- /dev/null
+++ b/fpga/usrp2/gpmc/fifo_to_gpmc_sync.v
@@ -0,0 +1,26 @@
+
+// Assumes a GPMC cycle with GPMC clock, as in the timing diagrams
+//   If a packet bigger or smaller than we are told is sent, behavior is undefined.
+//   If dst_rdy_i is low when we get data, behavior is undefined and we signal bus error.
+//   If there is a bus error, we should be reset
+
+module fifo_to_gpmc_sync
+  (input arst,
+   input [17:0] data_i, input src_rdy_i, output dst_rdy_o,
+   input EM_CLK, output [15:0] EM_D, input EM_NCS, input EM_NOE,
+   output fifo_ready, 
+   output reg bus_error);
+
+   assign EM_D = data_i[15:0];
+   wire       read_access = ~EM_NCS & ~EM_NOE;
+
+   assign dst_rdy_o = read_access;
+
+   always @(posedge EM_CLK or posedge arst)
+     if(arst)
+       bus_error <= 0;
+     else if(dst_rdy_o & ~src_rdy_i)
+       bus_error <= 1;
+   
+
+endmodule // fifo_to_gpmc_sync
diff --git a/fpga/usrp2/gpmc/fifo_watcher.v b/fpga/usrp2/gpmc/fifo_watcher.v
new file mode 100644
index 000000000..fe4e35de3
--- /dev/null
+++ b/fpga/usrp2/gpmc/fifo_watcher.v
@@ -0,0 +1,56 @@
+
+
+module fifo_watcher
+  (input clk, input reset, input clear,
+   input src_rdy1, input dst_rdy1, input sof1, input eof1,
+   input src_rdy2, input dst_rdy2, input sof2, input eof2,
+   output reg have_packet, output [15:0] length, output reg bus_error,
+   output [31:0] debug);
+
+   wire   write = src_rdy1 & dst_rdy1 & eof1;
+   wire   read = src_rdy2 & dst_rdy2 & eof2;
+   wire   have_packet_int;
+   reg [15:0] counter;
+   wire [4:0] pkt_count;
+   assign debug = pkt_count;
+   
+   fifo_short #(.WIDTH(16)) frame_lengths
+     (.clk(clk), .reset(reset), .clear(clear),
+      .datain(counter), .src_rdy_i(write), .dst_rdy_o(),
+      .dataout(length), .src_rdy_o(have_packet_int), .dst_rdy_i(read),
+      .occupied(pkt_count), .space());
+
+   always @(posedge clk)
+     if(reset | clear)
+       counter <= 1;   // Start at 1
+     else if(src_rdy1 & dst_rdy1)
+       if(eof1)
+	 counter <= 1;
+       else
+	 counter <= counter + 1;
+
+   always @(posedge clk)
+     if(reset | clear)
+       bus_error <= 0;
+     else if(dst_rdy2 & ~src_rdy2)
+       bus_error <= 1;
+     else if(read & ~have_packet_int)
+       bus_error <= 1;
+
+   reg 	      in_packet;
+   always @(posedge clk)
+     if(reset | clear)
+       have_packet <= 0;
+     else 
+       have_packet <= (have_packet_int & ~in_packet) | (pkt_count>1) ;
+   
+   always @(posedge clk)
+     if(reset | clear)
+       in_packet <= 0;
+     else if(src_rdy2 & dst_rdy2)
+       if(eof2)
+	 in_packet <= 0;
+       else
+	 in_packet <= 1;
+   
+endmodule // fifo_watcher
diff --git a/fpga/usrp2/gpmc/gpmc_async.v b/fpga/usrp2/gpmc/gpmc_async.v
new file mode 100644
index 000000000..23bad56ae
--- /dev/null
+++ b/fpga/usrp2/gpmc/gpmc_async.v
@@ -0,0 +1,130 @@
+//////////////////////////////////////////////////////////////////////////////////
+
+module gpmc_async
+  #(parameter TXFIFOSIZE = 11, parameter RXFIFOSIZE = 11)
+   (// GPMC signals
+    input arst,
+    input EM_CLK, inout [15:0] EM_D, input [10:1] EM_A, input [1:0] EM_NBE,
+    input EM_WAIT0, input EM_NCS4, input EM_NCS6, input EM_NWE, input EM_NOE,
+    
+    // GPIOs for FIFO signalling
+    output rx_have_data, output tx_have_space, output reg bus_error, input bus_reset,
+    
+    // Wishbone signals
+    input wb_clk, input wb_rst,
+    output [10:0] wb_adr_o, output [15:0] wb_dat_mosi, input [15:0] wb_dat_miso,
+    output [1:0] wb_sel_o, output wb_cyc_o, output wb_stb_o, output wb_we_o, input wb_ack_i,
+    
+    // FIFO interface
+    input fifo_clk, input fifo_rst, input clear_tx, input clear_rx,
+    output [35:0] tx_data_o, output tx_src_rdy_o, input tx_dst_rdy_i,
+    input [35:0] rx_data_i, input rx_src_rdy_i, output rx_dst_rdy_o,
+    
+    input [15:0] tx_frame_len, output [15:0] rx_frame_len,
+    
+    output [31:0] debug
+    );
+
+   wire 	  EM_output_enable = (~EM_NOE & (~EM_NCS4 | ~EM_NCS6));
+   wire [15:0] 	  EM_D_fifo;
+   wire [15:0] 	  EM_D_wb;
+   
+   assign EM_D = ~EM_output_enable ? 16'bz : ~EM_NCS4 ? EM_D_fifo : EM_D_wb;
+   
+   wire 	  bus_error_tx, bus_error_rx;
+   
+   always @(posedge fifo_clk)
+     if(fifo_rst | clear_tx | clear_rx)
+       bus_error <= 0;
+     else
+       bus_error <= bus_error_tx | bus_error_rx;
+   
+   // CS4 is RAM_2PORT for DATA PATH (high-speed data)
+   //    Writes go into one RAM, reads come from the other
+   // CS6 is for CONTROL PATH (wishbone)
+
+   // ////////////////////////////////////////////
+   // TX Data Path
+
+   wire [17:0] 	  tx18_data, tx18b_data;
+   wire 	  tx18_src_rdy, tx18_dst_rdy, tx18b_src_rdy, tx18b_dst_rdy;
+   wire [15:0] 	  tx_fifo_space;
+   wire [35:0] 	  tx36_data;
+   wire 	  tx36_src_rdy, tx36_dst_rdy;
+   
+   gpmc_to_fifo_async gpmc_to_fifo_async
+     (.EM_D(EM_D), .EM_NBE(EM_NBE), .EM_NCS(EM_NCS4), .EM_NWE(EM_NWE),
+      .fifo_clk(fifo_clk), .fifo_rst(fifo_rst), .clear(clear_tx),
+      .data_o(tx18_data), .src_rdy_o(tx18_src_rdy), .dst_rdy_i(tx18_dst_rdy),
+      .frame_len(tx_frame_len), .fifo_space(tx_fifo_space), .fifo_ready(tx_have_space),
+      .bus_error(bus_error_tx) );
+   
+   fifo_cascade #(.WIDTH(18), .SIZE(10)) tx_fifo
+     (.clk(fifo_clk), .reset(fifo_rst), .clear(clear_tx),
+      .datain(tx18_data), .src_rdy_i(tx18_src_rdy), .dst_rdy_o(tx18_dst_rdy), .space(tx_fifo_space),
+      .dataout(tx18b_data), .src_rdy_o(tx18b_src_rdy), .dst_rdy_i(tx18b_dst_rdy), .occupied());
+
+   fifo19_to_fifo36 #(.LE(1)) f19_to_f36   // Little endian because ARM is LE
+     (.clk(fifo_clk), .reset(fifo_rst), .clear(clear_tx),
+      .f19_datain({1'b0,tx18b_data}), .f19_src_rdy_i(tx18b_src_rdy), .f19_dst_rdy_o(tx18b_dst_rdy),
+      .f36_dataout(tx36_data), .f36_src_rdy_o(tx36_src_rdy), .f36_dst_rdy_i(tx36_dst_rdy));
+   
+   fifo_cascade #(.WIDTH(36), .SIZE(TXFIFOSIZE)) tx_fifo36
+     (.clk(wb_clk), .reset(wb_rst), .clear(clear_tx),
+      .datain(tx36_data), .src_rdy_i(tx36_src_rdy), .dst_rdy_o(tx36_dst_rdy),
+      .dataout(tx_data_o), .src_rdy_o(tx_src_rdy_o), .dst_rdy_i(tx_dst_rdy_i));
+
+   // ////////////////////////////////////////////
+   // RX Data Path
+   
+   wire [17:0] 	  rx18_data, rx18b_data;
+   wire 	  rx18_src_rdy, rx18_dst_rdy, rx18b_src_rdy, rx18b_dst_rdy;
+   wire [15:0] 	  rx_fifo_space;
+   wire [35:0] 	  rx36_data;
+   wire 	  rx36_src_rdy, rx36_dst_rdy;
+   wire 	  dummy;
+   
+   fifo_cascade #(.WIDTH(36), .SIZE(RXFIFOSIZE)) rx_fifo36
+     (.clk(wb_clk), .reset(wb_rst), .clear(clear_rx),
+      .datain(rx_data_i), .src_rdy_i(rx_src_rdy_i), .dst_rdy_o(rx_dst_rdy_o),
+      .dataout(rx36_data), .src_rdy_o(rx36_src_rdy), .dst_rdy_i(rx36_dst_rdy));
+
+   fifo36_to_fifo19 #(.LE(1)) f36_to_f19   // Little endian because ARM is LE
+     (.clk(fifo_clk), .reset(fifo_rst), .clear(clear_rx),
+      .f36_datain(rx36_data), .f36_src_rdy_i(rx36_src_rdy), .f36_dst_rdy_o(rx36_dst_rdy),
+      .f19_dataout({dummy,rx18_data}), .f19_src_rdy_o(rx18_src_rdy), .f19_dst_rdy_i(rx18_dst_rdy) );
+
+   fifo_cascade #(.WIDTH(18), .SIZE(12)) rx_fifo
+     (.clk(fifo_clk), .reset(fifo_rst), .clear(clear_rx),
+      .datain(rx18_data), .src_rdy_i(rx18_src_rdy), .dst_rdy_o(rx18_dst_rdy), .space(rx_fifo_space),
+      .dataout(rx18b_data), .src_rdy_o(rx18b_src_rdy), .dst_rdy_i(rx18b_dst_rdy), .occupied());
+
+   fifo_to_gpmc_async fifo_to_gpmc_async
+     (.clk(fifo_clk), .reset(fifo_rst), .clear(clear_rx),
+      .data_i(rx18b_data), .src_rdy_i(rx18b_src_rdy), .dst_rdy_o(rx18b_dst_rdy),
+      .EM_D(EM_D_fifo), .EM_NCS(EM_NCS4), .EM_NOE(EM_NOE),
+      .frame_len(rx_frame_len) );
+
+   wire [31:0] 	pkt_count;
+   
+   fifo_watcher fifo_watcher
+     (.clk(fifo_clk), .reset(fifo_rst), .clear(clear_rx),
+      .src_rdy1(rx18_src_rdy), .dst_rdy1(rx18_dst_rdy), .sof1(rx18_data[16]), .eof1(rx18_data[17]),
+      .src_rdy2(rx18b_src_rdy), .dst_rdy2(rx18b_dst_rdy), .sof2(rx18b_data[16]), .eof2(rx18b_data[17]),
+      .have_packet(rx_have_data), .length(rx_frame_len), .bus_error(bus_error_rx),
+      .debug(pkt_count));
+
+   // ////////////////////////////////////////////
+   // Control path on CS6
+   
+   gpmc_wb gpmc_wb
+     (.EM_CLK(EM_CLK), .EM_D_in(EM_D), .EM_D_out(EM_D_wb), .EM_A(EM_A), .EM_NBE(EM_NBE),
+      .EM_NCS(EM_NCS6), .EM_NWE(EM_NWE), .EM_NOE(EM_NOE),
+      .wb_clk(wb_clk), .wb_rst(wb_rst),
+      .wb_adr_o(wb_adr_o), .wb_dat_mosi(wb_dat_mosi), .wb_dat_miso(wb_dat_miso),
+      .wb_sel_o(wb_sel_o), .wb_cyc_o(wb_cyc_o), .wb_stb_o(wb_stb_o), .wb_we_o(wb_we_o),
+      .wb_ack_i(wb_ack_i) );
+   
+      assign debug = pkt_count;
+   
+endmodule // gpmc_async
diff --git a/fpga/usrp2/gpmc/gpmc_sync.v b/fpga/usrp2/gpmc/gpmc_sync.v
new file mode 100644
index 000000000..61c54a793
--- /dev/null
+++ b/fpga/usrp2/gpmc/gpmc_sync.v
@@ -0,0 +1,108 @@
+//////////////////////////////////////////////////////////////////////////////////
+
+module gpmc_sync
+  (// GPMC signals
+   input arst,
+   input EM_CLK, inout [15:0] EM_D, input [10:1] EM_A, input [1:0] EM_NBE,
+   input EM_WAIT0, input EM_NCS4, input EM_NCS6, input EM_NWE, input EM_NOE,
+   
+   // GPIOs for FIFO signalling
+   output rx_have_data, output tx_have_space, output bus_error, input bus_reset,
+   
+   // Wishbone signals
+   input wb_clk, input wb_rst,
+   output [10:0] wb_adr_o, output [15:0] wb_dat_mosi, input [15:0] wb_dat_miso,
+   output [1:0] wb_sel_o, output wb_cyc_o, output wb_stb_o, output wb_we_o, input wb_ack_i,
+
+   // FIFO interface
+   input fifo_clk, input fifo_rst,
+   output [35:0] tx_data_o, output tx_src_rdy_o, input tx_dst_rdy_i,
+   input [35:0] rx_data_i, input rx_src_rdy_i, output rx_dst_rdy_o,
+
+   output [31:0] debug
+   );
+
+   wire 	EM_output_enable = (~EM_NOE & (~EM_NCS4 | ~EM_NCS6));
+   wire [15:0] 	EM_D_fifo;
+   wire [15:0] 	EM_D_wb;
+
+   assign EM_D = ~EM_output_enable ? 16'bz : ~EM_NCS4 ? EM_D_fifo : EM_D_wb;
+
+   wire 	bus_error_tx, bus_error_rx;
+   assign bus_error = bus_error_tx | bus_error_rx;
+   
+   // CS4 is RAM_2PORT for DATA PATH (high-speed data)
+   //    Writes go into one RAM, reads come from the other
+   // CS6 is for CONTROL PATH (wishbone)
+
+   // ////////////////////////////////////////////
+   // TX Data Path
+
+   wire [17:0] 	tx18_data, tx18b_data;
+   wire 	tx18_src_rdy, tx18_dst_rdy, tx18b_src_rdy, tx18b_dst_rdy;
+   wire [15:0] 	tx_fifo_space, tx_frame_len;
+   
+   assign tx_frame_len = 10;
+   
+   gpmc_to_fifo_sync gpmc_to_fifo_sync
+     (.arst(arst),
+      .EM_CLK(EM_CLK), .EM_D(EM_D), .EM_NBE(EM_NBE), .EM_NCS(EM_NCS4), .EM_NWE(EM_NWE),
+      .data_o(tx18_data), .src_rdy_o(tx18_src_rdy), .dst_rdy_i(tx18_dst_rdy),
+      .frame_len(tx_frame_len), .fifo_space(tx_fifo_space), .fifo_ready(tx_have_space),
+      .bus_error(bus_error_tx) );
+   
+   fifo_2clock_cascade #(.WIDTH(18), .SIZE(4)) tx_fifo
+     (.wclk(EM_CLK), .datain(tx18_data), 
+      .src_rdy_i(tx18_src_rdy), .dst_rdy_o(tx18_dst_rdy), .space(tx_fifo_space),
+      .rclk(fifo_clk), .dataout(tx18b_data), 
+      .src_rdy_o(tx18b_src_rdy), .dst_rdy_i(tx18b_dst_rdy), .occupied(), .arst(arst));
+
+   fifo19_to_fifo36 #(.LE(1)) f19_to_f36   // Little endian because ARM is LE
+     (.clk(fifo_clk), .reset(fifo_rst), .clear(0),
+      .f19_datain({1'b0,tx18b_data}), .f19_src_rdy_i(tx18b_src_rdy), .f19_dst_rdy_o(tx18b_dst_rdy),
+      .f36_dataout(tx_data_o), .f36_src_rdy_o(tx_src_rdy_o), .f36_dst_rdy_i(tx_dst_rdy_i));
+   
+   // ////////////////////////////////////////////
+   // RX Data Path
+
+   wire [17:0] 	rx18_data, rx18b_data;
+   wire 	rx18_src_rdy, rx18_dst_rdy, rx18b_src_rdy, rx18b_dst_rdy;
+   wire [15:0] 	rx_fifo_space, rx_frame_len;
+   wire 	dummy;
+   
+   fifo36_to_fifo19 #(.LE(1)) f36_to_f19   // Little endian because ARM is LE
+     (.clk(fifo_clk), .reset(fifo_rst), .clear(0),
+      .f36_datain(rx_data_i), .f36_src_rdy_i(rx_src_rdy_i), .f36_dst_rdy_o(rx_dst_rdy_o),
+      .f19_dataout({dummy,rx18_data}), .f19_src_rdy_o(rx18_src_rdy), .f19_dst_rdy_i(rx18_dst_rdy) );
+
+   fifo_2clock_cascade #(.WIDTH(18), .SIZE(10)) rx_fifo
+     (.wclk(fifo_clk), .datain(rx18_data), 
+      .src_rdy_i(rx18_src_rdy), .dst_rdy_o(rx18_dst_rdy), .space(rx_fifo_space),
+      .rclk(EM_CLK), .dataout(rx18b_data), 
+      .src_rdy_o(rx18b_src_rdy), .dst_rdy_i(rx18b_dst_rdy), .occupied(), .arst(arst));
+
+   fifo_to_gpmc_sync fifo_to_gpmc_sync
+     (.arst(arst),
+      .data_i(rx18b_data), .src_rdy_i(rx18b_src_rdy), .dst_rdy_o(rx18b_dst_rdy),
+      .EM_CLK(EM_CLK), .EM_D(EM_D_fifo), .EM_NCS(EM_NCS4), .EM_NOE(EM_NOE),
+      .fifo_ready(rx_have_data) );
+
+   fifo_watcher fifo_watcher
+     (.clk(fifo_clk), .reset(fifo_rst), .clear(0),
+      .src_rdy(rx18_src_rdy), .dst_rdy(rx18_dst_rdy), .sof(rx18_data[16]), .eof(rx18_data[17]),
+      .have_packet(), .length(), .next() );
+   
+   // ////////////////////////////////////////////
+   // Control path on CS6
+   
+   gpmc_wb gpmc_wb
+     (.EM_CLK(EM_CLK), .EM_D_in(EM_D), .EM_D_out(EM_D_wb), .EM_A(EM_A), .EM_NBE(EM_NBE),
+      .EM_NCS(EM_NCS6), .EM_NWE(EM_NWE), .EM_NOE(EM_NOE),
+      .wb_clk(wb_clk), .wb_rst(wb_rst),
+      .wb_adr_o(wb_adr_o), .wb_dat_mosi(wb_dat_mosi), .wb_dat_miso(wb_dat_miso),
+      .wb_sel_o(wb_sel_o), .wb_cyc_o(wb_cyc_o), .wb_stb_o(wb_stb_o), .wb_we_o(wb_we_o),
+      .wb_ack_i(wb_ack_i) );
+   
+      assign debug = 0;
+   
+endmodule // gpmc_sync
diff --git a/fpga/usrp2/gpmc/gpmc_to_fifo_async.v b/fpga/usrp2/gpmc/gpmc_to_fifo_async.v
new file mode 100644
index 000000000..55c0cef50
--- /dev/null
+++ b/fpga/usrp2/gpmc/gpmc_to_fifo_async.v
@@ -0,0 +1,68 @@
+
+module gpmc_to_fifo_async
+  (input [15:0] EM_D, input [1:0] EM_NBE, input EM_NCS, input EM_NWE,
+
+   input fifo_clk, input fifo_rst, input clear,
+   output reg [17:0] data_o, output reg src_rdy_o, input dst_rdy_i,
+
+   input [15:0] frame_len, input [15:0] fifo_space, output reg fifo_ready,
+   output reg bus_error );
+
+   reg [15:0] counter;
+   // Synchronize the async control signals
+   reg [1:0] 	cs_del, we_del;
+   always @(posedge fifo_clk)
+     if(fifo_rst)
+       begin
+	  cs_del <= 2'b11;
+	  we_del <= 2'b11;
+       end
+     else
+       begin
+	  cs_del <= { cs_del[0], EM_NCS };
+	  we_del <= { we_del[0], EM_NWE };
+       end
+
+   wire do_write = (~cs_del[0] & (we_del == 2'b10));
+   wire first_write = (counter == 0);
+   wire last_write = ((counter+1) == frame_len);
+
+   always @(posedge fifo_clk)
+     if(do_write)
+       begin
+	  data_o[15:0] <= EM_D;
+	  data_o[16] <= first_write;
+	  data_o[17] <= last_write;
+	  //  no byte writes data_o[18] <= |EM_NBE;  // mark half full if either is not enabled  FIXME
+       end
+
+   always @(posedge fifo_clk)
+     if(fifo_rst | clear)
+       src_rdy_o <= 0;
+     else if(do_write)
+       src_rdy_o <= 1;
+     else
+       src_rdy_o <= 0;    // Assume it was taken
+
+   always @(posedge fifo_clk)
+     if(fifo_rst | clear)
+       counter <= 0;
+     else if(do_write)
+       if(last_write)
+	 counter <= 0;
+       else
+	 counter <= counter + 1;
+
+   always @(posedge fifo_clk)
+     if(fifo_rst | clear)
+       fifo_ready <= 0;
+     else
+       fifo_ready <= /* first_write & */ (fifo_space > 16'd1023);
+
+   always @(posedge fifo_clk)
+     if(fifo_rst | clear)
+       bus_error <= 0;
+     else if(src_rdy_o & ~dst_rdy_i)
+       bus_error <= 1;
+   
+endmodule // gpmc_to_fifo_async
diff --git a/fpga/usrp2/gpmc/gpmc_to_fifo_sync.v b/fpga/usrp2/gpmc/gpmc_to_fifo_sync.v
new file mode 100644
index 000000000..688de0e17
--- /dev/null
+++ b/fpga/usrp2/gpmc/gpmc_to_fifo_sync.v
@@ -0,0 +1,57 @@
+
+// Assumes a GPMC cycle with GPMC clock, as in the timing diagrams
+//   If a packet bigger or smaller than we are told is sent, behavior is undefined.
+//   If dst_rdy_i is low when we get data, behavior is undefined and we signal bus error.
+//   If there is a bus error, we should be reset
+
+module gpmc_to_fifo_sync
+  (input arst,
+   input EM_CLK, input [15:0] EM_D, input [1:0] EM_NBE,
+   input EM_NCS, input EM_NWE,
+   output reg [17:0] data_o, output reg src_rdy_o, input dst_rdy_i,
+   input [15:0] frame_len, input [15:0] fifo_space, output fifo_ready, 
+   output reg bus_error);
+   
+   reg [10:0] 	counter;
+   wire 	first_write = (counter == 0);
+   wire 	last_write = ((counter+1) == frame_len);
+   wire 	do_write = ~EM_NCS & ~EM_NWE;
+   
+   always @(posedge EM_CLK or posedge arst)
+     if(arst)
+       data_o <= 0;
+     else if(do_write)
+       begin
+	  data_o[15:0] <= EM_D;
+	  data_o[16] <= first_write;
+	  data_o[17] <= last_write;
+	  //  no byte writes data_o[18] <= |EM_NBE;  // mark half full if either is not enabled  FIXME
+       end
+
+   always @(posedge EM_CLK or posedge arst)
+     if(arst)
+       src_rdy_o <= 0;
+     else if(do_write & ~bus_error)  // Don't put junk in if there is a bus error
+       src_rdy_o <= 1;
+     else
+       src_rdy_o <= 0;    // Assume it was taken, ignore dst_rdy_i
+
+   always @(posedge EM_CLK or posedge arst)
+     if(arst)
+       counter <= 0;
+     else if(do_write)
+       if(last_write)
+	 counter <= 0;
+       else
+	 counter <= counter + 1;
+
+   assign fifo_ready = first_write & (fifo_space > frame_len);
+   
+   always @(posedge EM_CLK or posedge arst)
+     if(arst)
+       bus_error <= 0;
+     else if(src_rdy_o & ~dst_rdy_i)
+       bus_error <= 1;
+   // must be reset to make the error go away
+
+endmodule // gpmc_to_fifo_sync
diff --git a/fpga/usrp2/gpmc/gpmc_wb.v b/fpga/usrp2/gpmc/gpmc_wb.v
new file mode 100644
index 000000000..db6fbc6e9
--- /dev/null
+++ b/fpga/usrp2/gpmc/gpmc_wb.v
@@ -0,0 +1,57 @@
+
+
+module gpmc_wb
+  (input EM_CLK, input [15:0] EM_D_in, output [15:0] EM_D_out, input [10:1] EM_A, input [1:0] EM_NBE,
+   input EM_NCS, input EM_NWE, input EM_NOE,
+
+   input wb_clk, input wb_rst,
+   output reg [10:0] wb_adr_o, output reg [15:0] wb_dat_mosi, input [15:0] wb_dat_miso,
+   output reg [1:0] wb_sel_o, output wb_cyc_o, output reg wb_stb_o, output reg wb_we_o, input wb_ack_i);
+   
+   // ////////////////////////////////////////////
+   // Control Path, Wishbone bus bridge (wb master)
+   reg [1:0] 	cs_del, we_del, oe_del;
+
+   // Synchronize the async control signals
+   always @(posedge wb_clk)
+     begin
+	cs_del <= { cs_del[0], EM_NCS };
+	we_del <= { we_del[0], EM_NWE };
+	oe_del <= { oe_del[0], EM_NOE };
+     end
+
+   always @(posedge wb_clk)
+     if(cs_del == 2'b10)  // Falling Edge
+       wb_adr_o <= { EM_A, 1'b0 };
+
+   always @(posedge wb_clk)
+     if(we_del == 2'b10)  // Falling Edge
+       begin
+	  wb_dat_mosi <= EM_D_in;
+	  wb_sel_o <= ~EM_NBE;
+       end
+
+   reg [15:0] EM_D_hold;
+   
+   always @(posedge wb_clk)
+     if(wb_ack_i)
+       EM_D_hold <= wb_dat_miso;
+
+   assign EM_D_out = wb_ack_i ? wb_dat_miso : EM_D_hold;
+   
+   assign wb_cyc_o = wb_stb_o;
+
+   always @(posedge wb_clk)
+     if(~cs_del[0] & (we_del == 2'b10) )
+       wb_we_o <= 1;
+     else if(wb_ack_i)  // Turn off we when done.  Could also use we_del[0], others...
+       wb_we_o <= 0;
+
+   // FIXME should this look at cs_del[1]?
+   always @(posedge wb_clk)
+     if(~cs_del[0] & ((we_del == 2'b10) | (oe_del == 2'b10)))
+       wb_stb_o <= 1;
+     else if(wb_ack_i)
+       wb_stb_o <= 0;
+   
+endmodule // gpmc_wb
diff --git a/fpga/usrp2/gpmc/make_timing_diag b/fpga/usrp2/gpmc/make_timing_diag
new file mode 100755
index 000000000..03166ad35
--- /dev/null
+++ b/fpga/usrp2/gpmc/make_timing_diag
@@ -0,0 +1,6 @@
+#!/bin/sh
+drawtiming -o single_data_write.gif single_data_write.txt
+drawtiming -o single_data_read.gif single_data_read.txt
+drawtiming -o burst_data_write.gif burst_data_write.txt
+#drawtiming -o burst_data_read.gif burst_data_read.txt
+
diff --git a/fpga/usrp2/gpmc/ram_to_fifo.v b/fpga/usrp2/gpmc/ram_to_fifo.v
new file mode 100644
index 000000000..8549dcc35
--- /dev/null
+++ b/fpga/usrp2/gpmc/ram_to_fifo.v
@@ -0,0 +1,46 @@
+
+
+module ram_to_fifo
+  (input clk, input reset,
+   input [10:0] read_length,  // From the dbsm (?)
+   output read_en, output reg [8:0] read_addr, input [31:0] read_data, input read_ready, output read_done,
+   output [35:0] data_o, output src_rdy_o, input dst_rdy_i);
+
+   // read_length/2 = number of 32 bit lines, numbered 0 through read_length/2-1
+   wire [8:0] 	 last_line = (read_length[10:1]-1); 
+
+   reg 		 read_phase, sop;
+
+   assign read_en = (read_phase == 0) | dst_rdy_i;
+   assign src_rdy_o = (read_phase == 1);
+   
+   always @(posedge clk)
+     if(reset)
+       begin
+	  read_addr <= 0;
+	  read_phase <= 0;
+	  sop <= 1;
+       end
+     else
+       if(read_phase == 0)
+	 begin
+	    read_addr <= read_ready;
+	    read_phase <= read_ready;
+	 end
+       else if(dst_rdy_i)
+	 begin
+	    sop <= 0;
+	    if(read_addr == last_line)
+	      begin
+		 read_addr <= 0;
+		 read_phase <= 0;
+	      end
+	    else
+	      read_addr <= read_addr + 1;
+	 end
+   
+   assign read_done = (read_phase == 1) & (read_addr == last_line) & dst_rdy_i;
+   wire eop = (read_addr == last_line);
+   assign data_o = { 2'b00, eop, sop, read_data };
+   
+endmodule // ram_to_fifo
diff --git a/fpga/usrp2/gpmc/single_data_read.txt b/fpga/usrp2/gpmc/single_data_read.txt
new file mode 100644
index 000000000..1dc0e3a78
--- /dev/null
+++ b/fpga/usrp2/gpmc/single_data_read.txt
@@ -0,0 +1,12 @@
+# OMAP writes to FPGA
+# initialize the signals
+CLK=0,nWE=1,nCS=1,nOE=1,DATA=Z.
+CLK=1.
+CLK=0,nOE=0,nCS=0,DATA=RD_DATA.
+CLK=1.
+CLK=0.
+CLK=1.
+CLK=0,nOE=1,nCS=1,DATA=Z.
+CLK=1.
+
+
diff --git a/fpga/usrp2/gpmc/single_data_write.txt b/fpga/usrp2/gpmc/single_data_write.txt
new file mode 100644
index 000000000..287e3e2c1
--- /dev/null
+++ b/fpga/usrp2/gpmc/single_data_write.txt
@@ -0,0 +1,10 @@
+# OMAP writes to FPGA
+# initialize the signals
+CLK=0,nWE=1,nCS=1,nOE=1,DATA=Z.
+CLK=1.
+CLK=0,nWE=0,nCS=0,DATA=WR_DATA.
+CLK=1.
+CLK=0,nWE=1,nCS=1,DATA=Z.
+CLK=1.
+
+