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module channel_demux
#(parameter NUM_CHAN = 2, parameter CHAN_WIDTH = 2) ( //usb Side
input [31:0]usbdata_final,
input WR_final,
// TX Side
input reset,
input txclk,
output reg [CHAN_WIDTH:0] WR_channel,
output reg [31:0] ram_data,
output reg [CHAN_WIDTH:0] WR_done_channel );
/* Parse header and forward to ram */
reg [2:0]reader_state;
reg [4:0]channel ;
reg [6:0]read_length ;
// States
parameter IDLE = 3'd0;
parameter HEADER = 3'd1;
parameter WAIT = 3'd2;
parameter FORWARD = 3'd3;
`define CHANNEL 20:16
`define PKT_SIZE 127
wire [4:0] true_channel;
assign true_channel = (usbdata_final[`CHANNEL] == 5'h1f) ?
NUM_CHAN : (usbdata_final[`CHANNEL]);
always @(posedge txclk)
begin
if (reset)
begin
reader_state <= IDLE;
WR_channel <= 0;
WR_done_channel <= 0;
end
else
case (reader_state)
IDLE: begin
if (WR_final)
reader_state <= HEADER;
end
// Store channel and forware header
HEADER: begin
channel <= true_channel;
WR_channel[true_channel] <= 1;
ram_data <= usbdata_final;
read_length <= 7'd0 ;
reader_state <= WAIT;
end
WAIT: begin
WR_channel[channel] <= 0;
if (read_length == `PKT_SIZE)
reader_state <= IDLE;
else if (WR_final)
reader_state <= FORWARD;
end
FORWARD: begin
WR_channel[channel] <= 1;
ram_data <= usbdata_final;
read_length <= read_length + 7'd1;
reader_state <= WAIT;
end
default:
begin
//error handling
reader_state <= IDLE;
end
endcase
end
endmodule
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