source: sandbox/MultiChannelUSB/amplitude.v@ 120

module amplitude
        (
                input   wire                    clock, frame, reset,
                input   wire    [11:0]  cfg_data,
                input   wire    [1:0]   uwt_flag,
                input   wire    [11:0]  uwt_data,
                output  wire                    amp_good,
                output  wire    [11:0]  amp_data
        );

        reg                             state_reg, state_next;
        reg             [11:0]  minimum_reg, minimum_next;
        reg                             amp_good_reg, amp_good_next;
        reg             [11:0]  amp_data_reg, amp_data_next;
        reg             [11:0]  uwt_data_reg, uwt_data_next;

        always @(posedge clock)
        begin
                if (reset)
                begin
                        state_reg <= 1'b0;
                        minimum_reg <= 12'd0;
                        amp_good_reg <= 1'b0;
                        amp_data_reg <= 12'd0;
                        uwt_data_reg <= 12'd0;
                end
                else
                begin
                        state_reg <= state_next;
                        minimum_reg <= minimum_next;
                        amp_good_reg <= amp_good_next;
                        amp_data_reg <= amp_data_next;
                        uwt_data_reg <= uwt_data_next;
                end
        end
        
        always @*
        begin
                state_next = state_reg;
                minimum_next = minimum_reg;
                amp_good_next = amp_good_reg;
                amp_data_next = amp_data_reg;
                uwt_data_next = uwt_data_reg;
                
                case (state_reg)
                        0:
                        begin
                                if (frame)
                                begin
                                        uwt_data_next = uwt_data;
                                        amp_good_next = 1'b0;
                                        // minimum
                                        if (uwt_flag[0])
                                        begin
                                                minimum_next = uwt_data_reg;
                                        end
                                        else if ((uwt_flag[1]) & (uwt_data > minimum_reg))
                                        begin
                                                amp_data_next = uwt_data - minimum_reg;
                                                state_next = 1'b1;
                                        end
                end
                        end
                        
                        1:
                        begin
                                amp_good_next = (amp_data_reg >= cfg_data);
                                state_next = 1'b0;
                        end

                endcase
        end

        assign amp_good = amp_good_reg;
        assign amp_data = amp_data_reg;

endmodule