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`define DSP_CORE_TX_BASE 128
module tx_control
#(parameter FIFOSIZE = 10)
(input clk, input rst,
input set_stb, input [7:0] set_addr, input [31:0] set_data,
input [31:0] master_time,
output underrun,
// To Buffer interface
input [31:0] rd_dat_i,
input rd_sop_i,
input rd_eop_i,
output rd_read_o,
output rd_done_o,
output rd_error_o,
// To DSP Core
output [31:0] sample,
output run,
input strobe,
// FIFO Levels
output [15:0] fifo_occupied,
output fifo_full,
output fifo_empty,
// Debug
output [31:0] debug
);
// Buffer interface to internal FIFO
wire write_data, write_ctrl, full_data, full_ctrl;
wire read_data, read_ctrl, empty_data, empty_ctrl;
wire clear_state;
reg [1:0] xfer_state;
reg [2:0] held_flags;
localparam XFER_IDLE = 0;
localparam XFER_1 = 1;
localparam XFER_2 = 2;
localparam XFER_DATA = 3;
always @(posedge clk)
if(rst)
xfer_state <= XFER_IDLE;
else
if(clear_state)
xfer_state <= XFER_IDLE;
else
case(xfer_state)
XFER_IDLE :
if(rd_sop_i)
xfer_state <= XFER_1;
XFER_1 :
begin
xfer_state <= XFER_2;
held_flags <= rd_dat_i[2:0];
end
XFER_2 :
if(~full_ctrl)
xfer_state <= XFER_DATA;
XFER_DATA :
if(rd_eop_i & ~full_data)
xfer_state <= XFER_IDLE;
endcase // case(xfer_state)
assign write_data = (xfer_state == XFER_DATA) & ~full_data;
assign write_ctrl = (xfer_state == XFER_2) & ~full_ctrl;
assign rd_read_o = (xfer_state == XFER_1) | write_data | write_ctrl;
assign rd_done_o = 0; // Always take everything we're given
assign rd_error_o = 0; // Should we indicate overruns here?
wire [31:0] data_o;
wire sop_o, eop_o, eob, sob, send_imm;
wire [31:0] sendtime;
wire [4:0] occ_ctrl;
cascadefifo2 #(.WIDTH(34),.SIZE(FIFOSIZE)) txctrlfifo
(.clk(clk),.rst(rst),.clear(clear_state),
.datain({rd_sop_i,rd_eop_i,rd_dat_i}), .write(write_data), .full(full_data),
.dataout({sop_o,eop_o,data_o}), .read(read_data), .empty(empty_data),
.space(), .occupied(fifo_occupied) );
assign fifo_full = full_data;
assign fifo_empty = empty_data;
shortfifo #(.WIDTH(35)) ctrlfifo
(.clk(clk),.rst(rst),.clear(clear_state),
.datain({held_flags[2:0],rd_dat_i}), .write(write_ctrl), .full(full_ctrl),
.dataout({send_imm,sob,eob,sendtime}), .read(read_ctrl), .empty(empty_ctrl),
.space(), .occupied(occ_ctrl) );
// Internal FIFO to DSP interface
reg [2:0] ibs_state;
localparam IBS_IDLE = 0;
localparam IBS_WAIT = 1;
localparam IBS_RUNNING = 2;
localparam IBS_CONT_BURST = 3;
localparam IBS_UNDERRUN = 7;
wire [32:0] delta_time = {1'b0,sendtime}-{1'b0,master_time};
wire too_late = (delta_time[32:31] == 2'b11);
wire go_now = ( master_time == sendtime );
always @(posedge clk)
if(rst)
ibs_state <= IBS_IDLE;
else
case(ibs_state)
IBS_IDLE :
if(~empty_ctrl & ~empty_data)
ibs_state <= IBS_WAIT;
IBS_WAIT :
if(send_imm)
ibs_state <= IBS_RUNNING;
else if(too_late)
ibs_state <= IBS_UNDERRUN;
else if(go_now)
ibs_state <= IBS_RUNNING;
IBS_RUNNING :
if(strobe)
if(empty_data)
ibs_state <= IBS_UNDERRUN;
else if(eop_o)
if(eob)
ibs_state <= IBS_IDLE;
else
ibs_state <= IBS_CONT_BURST;
IBS_CONT_BURST :
if(~empty_ctrl) // & ~empty_data)
ibs_state <= IBS_RUNNING;
else if(strobe)
ibs_state <= IBS_UNDERRUN;
IBS_UNDERRUN : // FIXME Should probably clean everything out
if(clear_state)
ibs_state <= IBS_IDLE;
endcase // case(ibs_state)
assign read_ctrl = (ibs_state == IBS_RUNNING) & strobe & eop_o; // & ~empty_ctrl;
assign read_data = (ibs_state == IBS_RUNNING) & strobe & ~empty_data;
assign run = (ibs_state == IBS_RUNNING) | (ibs_state == IBS_CONT_BURST);
assign underrun = (ibs_state == IBS_UNDERRUN);
wire [7:0] interp_rate;
setting_reg #(.my_addr(`DSP_CORE_TX_BASE+3)) sr_3
(.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
.in(set_data),.out(),.changed(clear_state));
assign sample = data_o;
assign debug = { {16'b0},
{ read_data, write_data, read_ctrl, write_ctrl, xfer_state[1:0],full_ctrl,empty_ctrl },
{ occ_ctrl, eop_o, clear_state, underrun} };
endmodule // tx_control
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