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// Split vita packets longer than one GPIF frame, add padding on short frames
module packet_splitter
#(parameter FRAME_LEN=256)
(input clk, input reset, input clear,
input [7:0] frames_per_packet,
input [18:0] data_i,
input src_rdy_i,
output dst_rdy_o,
output [18:0] data_o,
output src_rdy_o,
input dst_rdy_i);
reg [1:0] state;
reg [15:0] length;
reg [15:0] frame_len;
reg [7:0] frame_count;
localparam PS_IDLE = 0;
localparam PS_FRAME = 1;
localparam PS_NEW_FRAME = 2;
localparam PS_PAD = 3;
wire eof_i = data_i[17];
always @(posedge clk)
if(reset | clear)
begin
state <= PS_IDLE;
frame_count <= 0;
end
else
case(state)
PS_IDLE :
if(src_rdy_i & dst_rdy_i)
begin
length <= { data_i[14:0],1'b0};
frame_len <= FRAME_LEN;
state <= PS_FRAME;
frame_count <= 1;
end
PS_FRAME :
if(src_rdy_i & dst_rdy_i)
if((frame_len == 2) & ((length == 2) | eof_i))
state <= PS_IDLE;
else if(frame_len == 2)
begin
length <= length - 1;
state <= PS_NEW_FRAME;
frame_count <= frame_count + 1;
end
else if((length == 2)|eof_i)
begin
frame_len <= frame_len - 1;
state <= PS_PAD;
end
else
begin
frame_len <= frame_len - 1;
length <= length - 1;
end
PS_NEW_FRAME :
if(src_rdy_i & dst_rdy_i)
begin
frame_len <= FRAME_LEN;
if((length == 2)|eof_i)
state <= PS_PAD;
else
begin
state <= PS_FRAME;
length <= length - 1;
end // else: !if((length == 2)|eof_i)
end // if (src_rdy_i & dst_rdy_i)
PS_PAD :
if(dst_rdy_i)
if(frame_len == 2)
state <= PS_IDLE;
else
frame_len <= frame_len - 1;
endcase // case (state)
wire next_state_is_idle = dst_rdy_i & (frame_len==2) &
( (state==PS_PAD) | ( (state==PS_FRAME) & src_rdy_i & ((length==2)|eof_i) ) );
assign dst_rdy_o = dst_rdy_i & (state != PS_PAD);
assign src_rdy_o = src_rdy_i | (state == PS_PAD);
wire eof_out = (frame_len == 2) & (state != PS_IDLE) & (state != PS_NEW_FRAME);
wire sof_out = (state == PS_IDLE) | (state == PS_NEW_FRAME);
wire occ_out = eof_out & next_state_is_idle & (frames_per_packet != frame_count);
wire [15:0] data_out = data_i[15:0];
assign data_o = {occ_out, eof_out, sof_out, data_out};
endmodule // packet_splitter
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