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[/] [instruction_list_pipelined_processor_with_peripherals/] [trunk/] [hdl/] [timer_all.v] - Blame information for rev 3

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1 3 maheshpalv 
 
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`include "timescale.v"
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`include "defines.v"
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module timer (clk, en, reset, type, preset, DN, TT, ACC);
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        input clk, en, reset;
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        input [`tcTypeLen-1:0] type;
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        input [`tcPresetLen-1:0] preset;
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        output DN, TT;
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        output [`tcAccLen-1:0] ACC;
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        reg DN, TT;
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        reg [`tcAccLen-1:0] ACC;
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        reg [`tcTypeLen-1:0]     TimerType;
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        reg [`tcTypeLen-1:0]     typeNext;
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        parameter       OnDelayTimer                    = `tcTypeLen'b0;
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        parameter       OffDelayTimer                   = `tcTypeLen'b1;
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        parameter       RetOnDelayTimer         = `tcTypeLen'b10;
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        parameter       defaultType                             = `tcTypeLen'b11;
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        always @ (type)
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        begin
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                case (type)
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                `timerType1             :       begin
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                                                                typeNext = OnDelayTimer;
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                                                                end
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                `timerType2             :       begin
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                                                                typeNext = OffDelayTimer;
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                                                                end
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                `timerType3             :       begin
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                                                                typeNext = RetOnDelayTimer;
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                                                                end
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                default                 :       begin
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                                                                $display("      Timer is defined for unknown type.\n Valid types: On-delay, Off-delay, retentive-on-delay");
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                                                                end
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                endcase
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        end
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        always @ (posedge clk or posedge reset)
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        begin
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                if (reset)
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                begin
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                        $write ("       timer module is reset   ");
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                        TimerType = defaultType;
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                end
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                else
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                begin
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                        TimerType = typeNext;
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                end
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        end
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        always @ (posedge clk)
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        begin
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                case (TimerType)
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                OnDelayTimer    :       begin
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                                                                                if (reset)
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                                                                                begin
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                                                                                        ACC = `tcAccLen'b0;
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                                                                                        DN = 1'b0;
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                                                                                        TT = 1'b0;
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                                                                                end
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                                                                                else
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                                                                                begin
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                                                                                        if (en)
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                                                                                        begin
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                                                                                                if (ACC < preset)
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                                                                                                begin
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                                                                                                        ACC = ACC + 1'b1;
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                                                                                                        DN = 1'b0;
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                                                                                                        TT = 1'b1;
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                                                                                                end
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                                                                                                else if (ACC >= preset)
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                                                                                                begin
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                                                                                                        ACC = ACC;
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                                                                                                        DN = 1'b1;
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                                                                                                        TT = 1'b0;
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                                                                                                end
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                                                                                        end
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                                                                                        else
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                                                                                        begin
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                                                                                                ACC = `tcAccLen'b0;     // if not enabled
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                                                                                                DN = 1'b0;
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                                                                                                TT = 1'b0;
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                                                                                        end
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                                                                                end
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                                                                        end     // end this case
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                OffDelayTimer   :       begin                                                   // not correct implementation!
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                                                                                if (reset)
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                                                                                begin
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                                                                                        ACC = `tcAccLen'b0;
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                                                                                        DN = 1'b0;
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                                                                                        TT = 1'b0;
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                                                                                end
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                                                                                else
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                                                                                begin
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                                                                                        if (!en)
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                                                                                        begin
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                                                                                                if (ACC < preset)
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                                                                                                begin
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                                                                                                        ACC = ACC + 1'b1;
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                                                                                                        DN = 1'b0;
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                                                                                                        TT = 1'b1;
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                                                                                                end
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                                                                                                else if (ACC >= preset)
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                                                                                                begin
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                                                                                                        ACC = ACC;
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                                                                                                        DN = 1'b1;
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                                                                                                        TT = 1'b0;
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                                                                                                end
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                                                                                        end
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                                                                                        else
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                                                                                        begin
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                                                                                                ACC = `tcAccLen'b0;     // if not enabled
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                                                                                                DN = 1'b0;
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                                                                                                TT = 1'b0;
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                                                                                        end
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                                                                                end
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                                                                        end     // end this case
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                RetOnDelayTimer :       begin
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                                                                                if (reset)
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                                                                                begin
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                                                                                        ACC = `tcAccLen'b0;
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                                                                                        DN = 1'b0;
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                                                                                        TT = 1'b0;
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                                                                                end
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                                                                                else
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                                                                                begin
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                                                                                        if (en)
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                                                                                        begin
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                                                                                                if (ACC < preset)
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                                                                                                begin
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                                                                                                        ACC = ACC + 1'b1;
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                                                                                                        DN = 1'b0;
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                                                                                                        TT = 1'b1;
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                                                                                                end
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                                                                                                else if (ACC >= preset)
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                                                                                                begin
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                                                                                                        ACC = ACC;
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                                                                                                        DN = 1'b1;
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                                                                                                        TT = 1'b0;
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                                                                                                end
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                                                                                        end
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                                                                                        else
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                                                                                        begin
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                                                                                                ACC = ACC;      // retain ACC
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                                                                                                DN = 1'b0;
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                                                                                                TT = 1'b0;
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                                                                                        end
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                                                                                end
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                                                                        end     // end this case
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                                default         :       begin
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                                                                        $display("      Error in timer type     ");
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                                                                        end
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                                endcase
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        end
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endmodule
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