diff options
Diffstat (limited to 'usrp2/control_lib/newfifo/ll8_to_fifo19.v')
-rw-r--r-- | usrp2/control_lib/newfifo/ll8_to_fifo19.v | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/usrp2/control_lib/newfifo/ll8_to_fifo19.v b/usrp2/control_lib/newfifo/ll8_to_fifo19.v new file mode 100644 index 000000000..af3b91afb --- /dev/null +++ b/usrp2/control_lib/newfifo/ll8_to_fifo19.v @@ -0,0 +1,73 @@ + +module ll8_to_fifo19 + (input clk, input reset, input clear, + input [7:0] ll_data, + input ll_sof_n, + input ll_eof_n, + input ll_src_rdy_n, + output ll_dst_rdy_n, + + output [18:0] f19_data, + output f19_src_rdy_o, + input f19_dst_rdy_i ); + + localparam XFER_EMPTY = 0; + localparam XFER_HALF = 1; + localparam XFER_HALF_WRITE = 3; + + // Why anybody would use active low in an FPGA is beyond me... + wire ll_sof = ~ll_sof_n; + wire ll_eof = ~ll_eof_n; + wire ll_src_rdy = ~ll_src_rdy_n; + wire ll_dst_rdy; + assign ll_dst_rdy_n = ~ll_dst_rdy; + + wire xfer_out = f19_src_rdy_o & f19_dst_rdy_i; + wire xfer_in = ll_src_rdy & ll_dst_rdy; + + reg hold_sof; + wire f19_sof, f19_eof, f19_occ; + + reg [1:0] state; + reg [7:0] hold_reg; + + always @(posedge clk) + if(ll_src_rdy & (state==XFER_EMPTY)) + hold_reg <= ll_data; + + always @(posedge clk) + if(ll_sof & (state==XFER_EMPTY)) + hold_sof <= 1; + else if(xfer_out) + hold_sof <= 0; + + always @(posedge clk) + if(reset | clear) + state <= XFER_EMPTY; + else + case(state) + XFER_EMPTY : + if(ll_src_rdy) + if(ll_eof) + state <= XFER_HALF_WRITE; + else + state <= XFER_HALF; + XFER_HALF : + if(ll_src_rdy & f19_dst_rdy_i) + state <= XFER_EMPTY; + XFER_HALF_WRITE : + if(f19_dst_rdy_i) + state <= XFER_EMPTY; + endcase // case (state) + + assign ll_dst_rdy = (state==XFER_EMPTY) | ((state==XFER_HALF)&f19_dst_rdy_i); + assign f19_src_rdy_o = (state==XFER_HALF_WRITE) | ((state==XFER_HALF)&ll_src_rdy); + + assign f19_sof = hold_sof | (ll_sof & (state==XFER_HALF)); + assign f19_eof = (state == XFER_HALF_WRITE) | ll_eof; + assign f19_occ = (state == XFER_HALF_WRITE); + + assign f19_data = {f19_occ,f19_eof,f19_sof,hold_reg,ll_data}; + +endmodule // ll8_to_fifo19 + |