From 05d77f772317de5d925301aa11bb9a880656dd05 Mon Sep 17 00:00:00 2001 From: Josh Blum Date: Thu, 15 Apr 2010 11:24:24 -0700 Subject: moved usrp1 and usrp2 fpga dirs into fpga subdirectory --- fpga/usrp2/udp/fifo19_rxrealign.v | 42 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 fpga/usrp2/udp/fifo19_rxrealign.v (limited to 'fpga/usrp2/udp/fifo19_rxrealign.v') diff --git a/fpga/usrp2/udp/fifo19_rxrealign.v b/fpga/usrp2/udp/fifo19_rxrealign.v new file mode 100644 index 000000000..35ad90951 --- /dev/null +++ b/fpga/usrp2/udp/fifo19_rxrealign.v @@ -0,0 +1,42 @@ + + +// Adds a junk line at the beginning of every packet, which the +// following stages should ignore. This gives us proper alignment due +// to the 14 byte ethernet header + +// Bit 18 -- odd length +// Bit 17 -- eof +// Bit 16 -- sof +// Bit 15:0 -- data + +module fifo19_rxrealign + (input clk, input reset, input clear, + input [18:0] datain, input src_rdy_i, output dst_rdy_o, + output [18:0] dataout, output src_rdy_o, input dst_rdy_i); + + reg rxre_state; + localparam RXRE_DUMMY = 0; + localparam RXRE_PKT = 1; + + assign dataout[18] = datain[18]; + assign dataout[17] = datain[17]; + assign dataout[16] = (rxre_state==RXRE_DUMMY) | (datain[17] & datain[16]); // allows for passing error signal + assign dataout[15:0] = datain[15:0]; + + always @(posedge clk) + if(reset | clear) + rxre_state <= RXRE_DUMMY; + else if(src_rdy_i & dst_rdy_i) + case(rxre_state) + RXRE_DUMMY : + rxre_state <= RXRE_PKT; + RXRE_PKT : + if(datain[17]) // if eof or error + rxre_state <= RXRE_DUMMY; + endcase // case (rxre_state) + + assign src_rdy_o = src_rdy_i & dst_rdy_i; // Send anytime both sides are ready + assign dst_rdy_o = src_rdy_i & dst_rdy_i & (rxre_state == RXRE_PKT); // Only consume after the dummy + +endmodule // fifo19_rxrealign + -- cgit v1.2.3