module chan_fifo_reader
- ( input reset,
- input tx_clock,
- input tx_strobe,
- input [31:0]adc_clock,
- input [3:0] samples_format,
- input [15:0] fifodata,
- input pkt_waiting,
- output reg rdreq,
- output reg skip,
- output reg [15:0]tx_q,
- output reg [15:0]tx_i,
- output reg overrun,
- output reg underrun) ;
-
+ ( reset, tx_clock, tx_strobe, adc_time, samples_format,
+ fifodata, pkt_waiting, rdreq, skip, tx_q, tx_i,
+ underrun, tx_empty, debug, rssi, threshhold) ;
+
+ input wire reset ;
+ input wire tx_clock ;
+ input wire tx_strobe ; //signal to output tx_i and tx_q
+ input wire [31:0] adc_time ; //current time
+ input wire [3:0] samples_format ;// not useful at this point
+ input wire [31:0] fifodata ; //the data input
+ input wire pkt_waiting ; //signal the next packet is ready
+ output reg rdreq ; //actually an ack to the current fifodata
+ output reg skip ; //finish reading current packet
+ output reg [15:0] tx_q ; //top 16 bit output of fifodata
+ output reg [15:0] tx_i ; //bottom 16 bit output of fifodata
+ output reg underrun ;
+ output reg tx_empty ; //cause 0 to be the output
+ input wire [31:0] rssi;
+ input wire [31:0] threshhold;
+
+ output wire [14:0] debug;
+ assign debug = {reader_state, trash, skip, timestamp[4:0], adc_time[4:0]};
// Should not be needed if adc clock rate < tx clock rate
- `define JITTER 5
+ // Used only to debug
+ `define JITTER 5
//Samples format
// 16 bits interleaved complex samples
- `define QI16 4'b0
+ `define QI16 4'b0
// States
- `define IDLE 4'd0
- `define READ 4'd1
- `define HEADER1 4'd2
- `define HEADER2 4'd3
- `define TIMESTAMP1 4'd4
- `define TIMESTAMP2 4'd5
- `define WAIT 4'd6
- `define WAITSTROBE 4'd7
- `define SENDWAIT 4'd8
- `define SEND 4'd9
- `define FEED 4'd10
- `define DISCARD 4'd11
+ parameter IDLE = 3'd0;
+ parameter HEADER = 3'd1;
+ parameter TIMESTAMP = 3'd2;
+ parameter WAIT = 3'd3;
+ parameter WAITSTROBE = 3'd4;
+ parameter SEND = 3'd5;
- // State registers
- reg[3:0] reader_state;
- reg[3:0] reader_next_state;
+ // Header format
+ `define PAYLOAD 8:2
+ `define ENDOFBURST 27
+ `define STARTOFBURST 28
+ `define RSSI_FLAG 15
+
+
+ /* State registers */
+ reg [2:0] reader_state;
+
+ reg [6:0] payload_len;
+ reg [6:0] read_len;
+ reg [31:0] timestamp;
+ reg burst;
+ reg trash;
+ reg rssi_flag;
- //Variables
- reg[8:0] payload_len;
- reg[8:0] read_len;
- reg[31:0] timestamp;
- reg burst;
- reg qsample;
- always @(posedge tx_clock)
- begin
- if (reset)
+ always @(posedge tx_clock)
+ begin
+ if (reset)
begin
- reader_state <= `IDLE;
- reader_next_state <= `IDLE;
- rdreq <= 0;
- skip <= 0;
- overrun <= 0;
- underrun <= 0;
- burst <= 0;
- qsample <= 1;
- end
+ reader_state <= IDLE;
+ rdreq <= 0;
+ skip <= 0;
+ underrun <= 0;
+ burst <= 0;
+ tx_empty <= 1;
+ tx_q <= 0;
+ tx_i <= 0;
+ trash <= 0;
+ rssi_flag <= 0;
+ end
else
- begin
- reader_state = reader_next_state;
+ begin
case (reader_state)
- `IDLE:
- begin
- if (pkt_waiting == 1)
- begin
- reader_next_state <= `READ;
- rdreq <= 1;
- underrun <= 0;
- end
- else if (burst == 1)
+ IDLE:
+ begin
+ /*
+ * reset all the variables and wait for a tx_strobe
+ * it is assumed that the ram connected to this fifo_reader
+ * is a short hand fifo meaning that the header to the next packet
+ * is already available to this fifo_reader when pkt_waiting is on
+ */
+ skip <=0;
+ if (pkt_waiting == 1)
+ begin
+ reader_state <= HEADER;
+ rdreq <= 1;
+ underrun <= 0;
+ end
+ else if (burst == 1)
underrun <= 1;
- end
-
- // Just wait for the fifo data to arrive
- `READ:
- begin
- reader_next_state <= `HEADER1;
- end
-
- // First part of the header
- `HEADER1:
- begin
- reader_next_state <= `HEADER2;
-
- //Check Start burst flag
- if (fifodata[3] == 1)
- burst <= 1;
- if (fifodata[4] == 1)
- burst <= 0;
- end
+ if (tx_strobe == 1)
+ tx_empty <= 1 ;
+ end
- // Read payload length
- `HEADER2:
- begin
- payload_len <= (fifodata & 16'h1FF);
- read_len <= 9'd0;
- reader_next_state <= `TIMESTAMP1;
- end
+ /* Process header */
+ HEADER:
+ begin
+ if (tx_strobe == 1)
+ tx_empty <= 1 ;
+
+ rssi_flag <= fifodata[`RSSI_FLAG]&fifodata[`STARTOFBURST];
+ //Check Start/End burst flag
+ if (fifodata[`STARTOFBURST] == 1
+ && fifodata[`ENDOFBURST] == 1)
+ burst <= 0;
+ else if (fifodata[`STARTOFBURST] == 1)
+ burst <= 1;
+ else if (fifodata[`ENDOFBURST] == 1)
+ burst <= 0;
- `TIMESTAMP1:
- begin
- timestamp <= {fifodata, 16'b0};
- rdreq <= 0;
- reader_next_state <= `TIMESTAMP2;
- end
-
- `TIMESTAMP2:
- begin
- timestamp <= timestamp + fifodata;
- reader_next_state <= `WAIT;
- end
+ if (trash == 1 && fifodata[`STARTOFBURST] == 0)
+ begin
+ skip <= 1;
+ reader_state <= IDLE;
+ rdreq <= 0;
+ end
+ else
+ begin
+ payload_len <= fifodata[`PAYLOAD] ;
+ read_len <= 0;
+ rdreq <= 1;
+ reader_state <= TIMESTAMP;
+ end
+ end
+
+ TIMESTAMP:
+ begin
+ timestamp <= fifodata;
+ reader_state <= WAIT;
+ if (tx_strobe == 1)
+ tx_empty <= 1 ;
+ rdreq <= 0;
+ end
- // Decide if we wait, send or discard samples
- `WAIT:
- begin
- // Wait a little bit more
- if (timestamp > adc_clock + `JITTER)
- reader_next_state <= `WAIT;
+ // Decide if we wait, send or discard samples
+ WAIT:
+ begin
+ if (tx_strobe == 1)
+ tx_empty <= 1 ;
+
// Let's send it
- else if ((timestamp < adc_clock + `JITTER
- && timestamp > adc_clock)
- || timestamp == 32'hFFFFFFFF)
- begin
- reader_next_state <= `WAITSTROBE;
- end
+ if ((timestamp <= adc_time + `JITTER
+ && timestamp > adc_time)
+ || timestamp == 32'hFFFFFFFF)
+ begin
+ if (rssi <= threshhold || rssi_flag == 0)
+ begin
+ trash <= 0;
+ reader_state <= WAITSTROBE;
+ end
+ else
+ reader_state <= WAIT;
+ end
+ // Wait a little bit more
+ else if (timestamp > adc_time + `JITTER)
+ reader_state <= WAIT;
// Outdated
- else if (timestamp < adc_clock)
- begin
- reader_next_state <= `DISCARD;
- skip <= 1;
+ else if (timestamp < adc_time)
+ begin
+ trash <= 1;
+ reader_state <= IDLE;
+ skip <= 1;
end
- end
+ end
- // Wait for the transmit chain to be ready
- `WAITSTROBE:
- begin
- // If end of payload...
- if (read_len == payload_len)
+ // Wait for the transmit chain to be ready
+ WAITSTROBE:
+ begin
+ // If end of payload...
+ if (read_len == payload_len)
+ begin
+ reader_state <= IDLE;
+ skip <= 1;
+ if (tx_strobe == 1)
+ tx_empty <= 1 ;
+ end
+ else if (tx_strobe == 1)
+ begin
+ reader_state <= SEND;
+ rdreq <= 1;
+ end
+ end
+
+ // Send the samples to the tx_chain
+ SEND:
+ begin
+ reader_state <= WAITSTROBE;
+ read_len <= read_len + 7'd1;
+ tx_empty <= 0;
+ rdreq <= 0;
+
+ case(samples_format)
+ `QI16:
begin
- reader_next_state <= `DISCARD;
- skip <= (payload_len < 508);
+ tx_i <= fifodata[15:0];
+ tx_q <= fifodata[31:16];
end
-
- if (tx_strobe == 1)
- reader_next_state <= `SENDWAIT;
- end
-
- `SENDWAIT:
- begin
- rdreq <= 1;
- reader_next_state <= `SEND;
- end
-
- // Send the samples to the tx_chain
- `SEND:
- begin
- reader_next_state <= `WAITSTROBE;
- rdreq <= 0;
- read_len <= read_len + 2;
- case(samples_format)
- `QI16:
- begin
- tx_q <= qsample ? fifodata : 16'bZ;
- tx_i <= ~qsample ? fifodata : 16'bZ;
- qsample <= ~ qsample;
- end
+
+ // Assume 16 bits complex samples by default
default:
- begin
- // Assume 16 bits complex samples by default
- $display ("Error unknown samples format");
- tx_q <= qsample ? fifodata : 16'bZ;
- tx_i <= ~qsample ? fifodata : 16'bZ;
- qsample <= ~ qsample;
- end
- endcase
- end
-
- `DISCARD:
- begin
- skip <= 0;
- reader_next_state <= `IDLE;
- end
+ begin
+ tx_i <= fifodata[15:0];
+ tx_q <= fifodata[31:16];
+ end
+ endcase
+ end
default:
- begin
- $display ("Error unknown state");
- reader_state <= `IDLE;
- reader_next_state <= `IDLE;
- end
+ begin
+ //error handling
+ reader_state <= IDLE;
+ end
endcase
end
end
-endmodule
\ No newline at end of file
+endmodule
projects / debian / gnuradio / blobdiff