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module gen_context_pkt
#(parameter PROT_ENG_FLAGS=1)
(input clk, input reset, input clear,
input trigger, output sent,
input [31:0] streamid,
input [63:0] vita_time,
input [31:0] message,
input [31:0] seqnum,
output [35:0] data_o, output src_rdy_o, input dst_rdy_i);
localparam CTXT_IDLE = 0;
localparam CTXT_PROT_ENG = 1;
localparam CTXT_HEADER = 2;
localparam CTXT_STREAMID = 3;
localparam CTXT_SECS = 4;
localparam CTXT_TICS = 5;
localparam CTXT_TICS2 = 6;
localparam CTXT_MESSAGE = 7;
localparam CTXT_FLOWCTRL = 8;
localparam CTXT_DONE = 9;
reg [33:0] data_int;
wire src_rdy_int, dst_rdy_int;
reg [3:0] seqno;
reg [3:0] ctxt_state;
reg [63:0] err_time;
reg [31:0] stored_message;
always @(posedge clk)
if(reset | clear)
stored_message <= 0;
else
if(trigger)
stored_message <= message;
else if(ctxt_state == CTXT_DONE)
stored_message <= 0;
// Don't want to clear most of this to avoid getting stuck with a half packet in the pipe
always @(posedge clk)
if(reset)
begin
ctxt_state <= CTXT_IDLE;
seqno <= 0;
end
else
case(ctxt_state)
CTXT_IDLE :
if(trigger)
begin
err_time <= vita_time;
if(PROT_ENG_FLAGS)
ctxt_state <= CTXT_PROT_ENG;
else
ctxt_state <= CTXT_HEADER;
end
CTXT_DONE :
begin
ctxt_state <= CTXT_IDLE;
seqno <= seqno + 4'd1;
end
default :
if(dst_rdy_int)
ctxt_state <= ctxt_state + 1;
endcase // case (ctxt_state)
assign src_rdy_int = ~( (ctxt_state == CTXT_IDLE) | (ctxt_state == CTXT_DONE) );
always @*
case(ctxt_state)
CTXT_PROT_ENG : data_int <= { 2'b01, 16'd1, 16'd32 };
CTXT_HEADER : data_int <= { 1'b0, (PROT_ENG_FLAGS ? 1'b0 : 1'b1), 12'b010100001101, seqno, 16'd7 };
CTXT_STREAMID : data_int <= { 2'b00, streamid };
CTXT_SECS : data_int <= { 2'b00, err_time[63:32] };
CTXT_TICS : data_int <= { 2'b00, 32'd0 };
CTXT_TICS2 : data_int <= { 2'b00, err_time[31:0] };
CTXT_MESSAGE : data_int <= { 2'b00, message };
CTXT_FLOWCTRL : data_int <= { 2'b10, seqnum };
default : data_int <= {2'b00, 32'b00};
endcase // case (ctxt_state)
fifo_short #(.WIDTH(34)) ctxt_fifo
(.clk(clk), .reset(reset), .clear(0),
.datain(data_int), .src_rdy_i(src_rdy_int), .dst_rdy_o(dst_rdy_int),
.dataout(data_o[33:0]), .src_rdy_o(src_rdy_o), .dst_rdy_i(dst_rdy_i));
assign data_o[35:34] = 2'b00;
endmodule // gen_context_pkt
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