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qaztronic |
// --------------------------------------------------------------------
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//
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// --------------------------------------------------------------------
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module
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buffered_gear_box(
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input [12:0] adc_bus,
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output adc_data_stall,
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output [7:0] out,
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input clk_1250,
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input clk_250,
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input sys_reset
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);
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// --------------------------------------------------------------------
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//
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reg [3:0] gear_select;
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wire gear_reset = sys_reset | ~(gear_select < 4'hc);
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always @( posedge clk_250 )
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if( gear_reset )
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gear_select <= 0;
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else
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gear_select <= gear_select + 1;
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// --------------------------------------------------------------------
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//
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reg load_shift_r_select;
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always @( posedge clk_250 )
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if( sys_reset )
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load_shift_r_select <= 0;
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else if( gear_reset )
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load_shift_r_select <= ~load_shift_r_select;
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// --------------------------------------------------------------------
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//
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reg [3:0] counter;
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wire shift_en = (~gear_reset) & (counter < 4'h8);
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always @( posedge clk_1250 )
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if( gear_reset )
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counter <= 0;
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else if( shift_en )
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counter <= counter + 1;
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// --------------------------------------------------------------------
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//
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reg [103:0] shift_b0_r;
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reg [103:0] shift_b1_r;
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always @( posedge clk_1250 )
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if( ~load_shift_r_select & shift_en )
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shift_b0_r <= {adc_bus, shift_b0_r[103:13]};
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always @( posedge clk_1250 )
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if( load_shift_r_select & shift_en )
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shift_b1_r <= {adc_bus, shift_b1_r[103:13]};
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// --------------------------------------------------------------------
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//
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reg [7:0] shift_b0_r_mux;
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always @( * )
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case( gear_select )
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4'h0: shift_b0_r_mux = shift_b0_r[7:0];
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4'h1: shift_b0_r_mux = shift_b0_r[15:8];
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4'h2: shift_b0_r_mux = shift_b0_r[23:16];
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4'h3: shift_b0_r_mux = shift_b0_r[31:24];
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4'h4: shift_b0_r_mux = shift_b0_r[39:32];
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4'h5: shift_b0_r_mux = shift_b0_r[47:40];
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4'h6: shift_b0_r_mux = shift_b0_r[55:48];
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4'h7: shift_b0_r_mux = shift_b0_r[63:56];
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4'h8: shift_b0_r_mux = shift_b0_r[71:64];
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4'h9: shift_b0_r_mux = shift_b0_r[79:72];
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4'ha: shift_b0_r_mux = shift_b0_r[87:80];
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4'hb: shift_b0_r_mux = shift_b0_r[95:88];
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4'hc: shift_b0_r_mux = shift_b0_r[103:96];
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default: shift_b0_r_mux = shift_b0_r[7:0];
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endcase
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// --------------------------------------------------------------------
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//
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reg [7:0] shift_b1_r_mux;
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always @( * )
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case( gear_select )
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4'h0: shift_b1_r_mux = shift_b1_r[7:0];
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4'h1: shift_b1_r_mux = shift_b1_r[15:8];
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4'h2: shift_b1_r_mux = shift_b1_r[23:16];
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4'h3: shift_b1_r_mux = shift_b1_r[31:24];
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4'h4: shift_b1_r_mux = shift_b1_r[39:32];
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4'h5: shift_b1_r_mux = shift_b1_r[47:40];
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4'h6: shift_b1_r_mux = shift_b1_r[55:48];
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4'h7: shift_b1_r_mux = shift_b1_r[63:56];
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4'h8: shift_b1_r_mux = shift_b1_r[71:64];
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4'h9: shift_b1_r_mux = shift_b1_r[79:72];
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4'ha: shift_b1_r_mux = shift_b1_r[87:80];
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4'hb: shift_b1_r_mux = shift_b1_r[95:88];
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4'hc: shift_b1_r_mux = shift_b1_r[103:96];
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default: shift_b1_r_mux = shift_b1_r[7:0];
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endcase
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// --------------------------------------------------------------------
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//
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assign adc_data_stall = ~shift_en;
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assign out = load_shift_r_select ? shift_b0_r_mux : shift_b1_r_mux;
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endmodule
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