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module time_sender
(input clk, input rst,
input [31:0] master_time,
input send_sync,
output exp_pps_out);
reg [7:0] datain;
reg k;
wire [9:0] dataout;
reg [9:0] dataout_reg;
reg disp_reg;
wire disp, new_word;
encode_8b10b encode_8b10b
(.datain({k,datain}),.dispin(disp_reg),
.dataout(dataout),.dispout(disp));
assign exp_pps_out = dataout_reg[0];
always @(posedge clk)
if(rst)
disp_reg <= 0;
else if(new_word)
disp_reg <= disp;
always @(posedge clk)
if(rst)
dataout_reg <= 0;
else if(new_word)
dataout_reg <= dataout;
else
dataout_reg <= {1'b0,dataout_reg[9:1]};
reg [4:0] state;
reg [3:0] bit_count;
assign new_word = (bit_count == 9);
always @(posedge clk)
if(rst)
bit_count <= 0;
else if(new_word | send_sync)
bit_count <= 0;
else
bit_count <= bit_count + 1;
localparam SEND_IDLE = 0;
localparam SEND_HEAD = 1;
localparam SEND_T0 = 2;
localparam SEND_T1 = 3;
localparam SEND_T2 = 4;
localparam SEND_T3 = 5;
localparam COMMA = 8'hBC;
localparam HEAD = 8'h3C;
reg [31:0] master_time_reg;
always @(posedge clk)
if(rst)
master_time_reg <= 0;
else if(send_sync)
master_time_reg <= master_time;
always @(posedge clk)
if(rst)
begin
{k,datain} <= 0;
state <= SEND_IDLE;
end
else
if(send_sync)
state <= SEND_HEAD;
else if(new_word)
case(state)
SEND_IDLE :
{k,datain} <= {1'b1,COMMA};
SEND_HEAD :
begin
{k,datain} <= {1'b1, HEAD};
state <= SEND_T0;
end
SEND_T0 :
begin
{k,datain} <= {1'b0, master_time_reg[31:24] };
state <= SEND_T1;
end
SEND_T1 :
begin
{k,datain} <= {1'b0, master_time_reg[23:16]};
state <= SEND_T2;
end
SEND_T2 :
begin
{k,datain} <= {1'b0, master_time_reg[15:8]};
state <= SEND_T3;
end
SEND_T3 :
begin
{k,datain} <= {1'b0, master_time_reg[7:0]};
state <= SEND_IDLE;
end
default :
state <= SEND_IDLE;
endcase // case(state)
endmodule // time_sender
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