diff options
Diffstat (limited to 'fpga/usrp2/timing/time_receiver.v')
| -rw-r--r-- | fpga/usrp2/timing/time_receiver.v | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/fpga/usrp2/timing/time_receiver.v b/fpga/usrp2/timing/time_receiver.v new file mode 100644 index 000000000..a03337552 --- /dev/null +++ b/fpga/usrp2/timing/time_receiver.v @@ -0,0 +1,157 @@ +// +// Copyright 2011 Ettus Research LLC +// +// This program is free software: you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program. If not, see <http://www.gnu.org/licenses/>. +// + + +module time_receiver + (input clk, input rst, + output reg [63:0] vita_time, + output reg sync_rcvd, + input exp_time_in); + + wire code_err, disp_err, dispout, complete_word; + reg disp_reg; + reg [9:0] shiftreg; + reg [3:0] bit_count; + wire [8:0] dataout; + reg [8:0] dataout_reg; + + reg exp_time_in_reg, exp_time_in_reg2; + + always @(posedge clk) exp_time_in_reg <= exp_time_in; + always @(posedge clk) exp_time_in_reg2 <= exp_time_in_reg; + + always @(posedge clk) + shiftreg <= {exp_time_in_reg2, shiftreg[9:1]}; + + localparam COMMA_0 = 10'h283; + localparam COMMA_1 = 10'h17c; + + wire found_comma = (shiftreg == COMMA_0) | (shiftreg == COMMA_1); + wire set_disp = (shiftreg == COMMA_1); + + always @(posedge clk) + if(rst) + bit_count <= 0; + else if(found_comma | complete_word) + bit_count <= 0; + else + bit_count <= bit_count + 1; + assign complete_word = (bit_count == 9); + + always @(posedge clk) + if(set_disp) + disp_reg <= 1; + else if(complete_word) + disp_reg <= dispout; + + always @(posedge clk) + if(complete_word) + dataout_reg <= dataout; + + decode_8b10b decode_8b10b + (.datain(shiftreg),.dispin(disp_reg), + .dataout(dataout),.dispout(dispout), + .code_err(code_err),.disp_err(disp_err) ); + + reg error; + always @(posedge clk) + if(complete_word) + error <= code_err | disp_err; + + localparam STATE_IDLE = 0; + localparam STATE_T0 = 1; + localparam STATE_T1 = 2; + localparam STATE_T2 = 3; + localparam STATE_T3 = 4; + localparam STATE_T4 = 5; + localparam STATE_T5 = 6; + localparam STATE_T6 = 7; + localparam STATE_T7 = 8; + localparam STATE_TAIL = 9; + + localparam HEAD = 9'h13c; + localparam TAIL = 9'h1F7; + + reg [3:0] state; + reg [63:0] vita_time_pre; + reg sync_rcvd_pre; + + always @(posedge clk) + if(rst) + state <= STATE_IDLE; + else if(complete_word) + if(code_err | disp_err) + state <= STATE_IDLE; + else + case(state) + STATE_IDLE : + if(dataout_reg == HEAD) + state <= STATE_T0; + STATE_T0 : + begin + vita_time_pre[63:56] <= dataout_reg[7:0]; + state <= STATE_T1; + end + STATE_T1 : + begin + vita_time_pre[55:48] <= dataout_reg[7:0]; + state <= STATE_T2; + end + STATE_T2 : + begin + vita_time_pre[47:40] <= dataout_reg[7:0]; + state <= STATE_T3; + end + STATE_T3 : + begin + vita_time_pre[39:32] <= dataout_reg[7:0]; + state <= STATE_T4; + end + STATE_T4 : + begin + vita_time_pre[31:24] <= dataout_reg[7:0]; + state <= STATE_T5; + end + STATE_T5 : + begin + vita_time_pre[23:16] <= dataout_reg[7:0]; + state <= STATE_T6; + end + STATE_T6 : + begin + vita_time_pre[15:8] <= dataout_reg[7:0]; + state <= STATE_T7; + end + STATE_T7 : + begin + vita_time_pre[7:0] <= dataout_reg[7:0]; + state <= STATE_TAIL; + end + STATE_TAIL : + state <= STATE_IDLE; + endcase // case(state) + + always @(posedge clk) + if(rst) + sync_rcvd_pre <= 0; + else + sync_rcvd_pre <= (complete_word & (state == STATE_TAIL) & (dataout_reg[8:0] == TAIL)); + + always @(posedge clk) sync_rcvd <= sync_rcvd_pre; + always @(posedge clk) vita_time <= vita_time_pre; + +endmodule // time_sender |