1 files changed, 98 insertions, 0 deletions
diff --git a/fpga/usrp2/fifo/dsp_framer36.v b/fpga/usrp2/fifo/dsp_framer36.v
new file mode 100644
index 000000000..34a05d91e
--- /dev/null
+++ b/fpga/usrp2/fifo/dsp_framer36.v
@@ -0,0 +1,98 @@
+
+// Frame DSP packets with a header line to be handled by the protocol machine
+
+module dsp_framer36
+    #(parameter BUF_SIZE = 9)
+    (
+        input clk, input rst, input clr,
+        input [35:0] inp_data, input inp_valid, output inp_ready,
+        output [35:0] out_data, output out_valid, input out_ready
+    );
+
+    localparam DSP_FRM_STATE_WAIT_SOF = 0;
+    localparam DSP_FRM_STATE_WAIT_EOF = 1;
+    localparam DSP_FRM_STATE_WRITE_HDR = 2;
+    localparam DSP_FRM_STATE_WRITE = 3;
+
+    reg [1:0] dsp_frm_state;
+    reg [BUF_SIZE-1:0] dsp_frm_addr;
+    reg [BUF_SIZE-1:0] dsp_frm_count;
+    wire [BUF_SIZE-1:0] dsp_frm_addr_next = dsp_frm_addr + 1'b1;
+
+    //DSP input stream ready in the following states
+    assign inp_ready = (
+        dsp_frm_state == DSP_FRM_STATE_WAIT_SOF ||
+        dsp_frm_state == DSP_FRM_STATE_WAIT_EOF
+    )? 1'b1 : 1'b0;
+
+    //DSP framer output data mux (header or BRAM):
+    //The header is generated here from the count.
+    wire [31:0] dsp_frm_data_bram;
+    wire [15:0] dsp_frm_bytes = {dsp_frm_count, 2'b00};
+    assign out_data =
+        (dsp_frm_state == DSP_FRM_STATE_WRITE_HDR)? {4'b0001, 16'b1, dsp_frm_bytes} : (
+        (dsp_frm_addr == dsp_frm_count)           ? {4'b0010, dsp_frm_data_bram}    : (
+    {4'b0000, dsp_frm_data_bram}));
+    assign out_valid = (
+        (dsp_frm_state == DSP_FRM_STATE_WRITE_HDR) ||
+        (dsp_frm_state == DSP_FRM_STATE_WRITE)
+    )? 1'b1 : 1'b0;
+
+    RAMB16_S36_S36 dsp_frm_buff(
+        //port A = DSP input interface (writes to BRAM)
+        .DOA(),.ADDRA(dsp_frm_addr),.CLKA(clk),.DIA(inp_data[31:0]),.DIPA(4'h0),
+        .ENA(inp_ready & inp_valid),.SSRA(0),.WEA(inp_ready & inp_valid),
+        //port B = DSP framer interface (reads from BRAM)
+        .DOB(dsp_frm_data_bram),.ADDRB(dsp_frm_addr),.CLKB(clk),.DIB(36'b0),.DIPB(4'h0),
+        .ENB(out_ready & out_valid),.SSRB(0),.WEB(1'b0)
+    );
+
+    always @(posedge clk)
+    if(rst | clr) begin
+        dsp_frm_state <= DSP_FRM_STATE_WAIT_SOF;
+        dsp_frm_addr <= 0;
+    end
+    else begin
+        case(dsp_frm_state)
+        DSP_FRM_STATE_WAIT_SOF: begin
+            if (inp_ready & inp_valid & inp_data[32]) begin
+                dsp_frm_addr <= dsp_frm_addr_next;
+                dsp_frm_state <= DSP_FRM_STATE_WAIT_EOF;
+            end
+        end
+
+        DSP_FRM_STATE_WAIT_EOF: begin
+            if (inp_ready & inp_valid) begin
+                if (inp_data[33]) begin
+                    dsp_frm_count <= dsp_frm_addr_next;
+                    dsp_frm_addr <= 0;
+                    dsp_frm_state <= DSP_FRM_STATE_WRITE_HDR;
+                end
+                else begin
+                    dsp_frm_addr <= dsp_frm_addr_next;
+                end
+            end
+        end
+
+        DSP_FRM_STATE_WRITE_HDR: begin
+            if (out_ready & out_valid) begin
+                dsp_frm_addr <= dsp_frm_addr_next;
+                dsp_frm_state <= DSP_FRM_STATE_WRITE;
+            end
+        end
+
+        DSP_FRM_STATE_WRITE: begin
+            if (out_ready & out_valid) begin
+                if (out_data[33]) begin
+                    dsp_frm_addr <= 0;
+                    dsp_frm_state <= DSP_FRM_STATE_WAIT_SOF;
+                end
+                else begin
+                    dsp_frm_addr <= dsp_frm_addr_next;
+                end
+            end
+        end
+        endcase //dsp_frm_state
+    end
+
+endmodule //dsp_framer36