module QuadSPIm(
    input Clk_i,
    input Rst_i,
    input Start_i,
    input CPHA_i,
    input [31:0] SPIdata,
    input SELST_i,
    input [1:0] WidthSel_i,
    input [1:0] LAG_i,
    input [1:0] LEAD_i,
    input EndianSel_i,
    input [1:0] Stop_i,
    input PulsePol_i,


    output reg Mosi0_i,
    output reg Mosi1_i,
    output reg Mosi2_i,
    output reg Mosi3_i,
    output reg  Sck_o,
    output reg Val_o,
    output Ss_o

);
//================================================================================
//  REG/WIRE
//================================================================================
reg startFlag;
reg [2:0] ssCnt;
reg Ss;
reg SSr;
reg [6:0] mosiReg0;
reg [6:0] mosiReg1;
reg [6:0] mosiReg2;
reg [6:0] mosiReg3;
reg [3:0] ssNum;
reg [2:0] delayCnt;
reg stopFlag;

wire SsPol = SELST_i ? Ss : ~Ss;

//================================================================================
//  ASSIGNMENTS
//================================================================================

assign Ss_o = SsPol; 

//================================================================================
//  CODING
//================================================================================	


always @(posedge Clk_i) begin 
    if (Rst_i) begin 
        delayCnt <= 1'b0;
    end
    else begin 
        if (stopFlag &&delayCnt < Stop_i) begin 
            delayCnt <= delayCnt + 1'b1;
        end
        else begin 
            delayCnt <= 1'b0;
        end
    end
end

always @(posedge Clk_i) begin 
    if (Rst_i) begin 
        stopFlag <= 1'b0;
    end
    else begin
        if (SELST_i) begin 
            if (Ss && !SSr) begin 
                stopFlag <= 1'b1;
            end
            else if ( delayCnt == Stop_i) begin 
                stopFlag <= 1'b0;
            end
        end
        else begin 
            if (!Ss && SSr) begin 
                stopFlag <= 1'b1;
            end
            else if (delayCnt == Stop_i) begin 
                stopFlag <= 1'b0;
            end
        end
    end
end



always @(*) begin 
    if (PulsePol_i) begin 
        if (CPHA_i) begin
            if (LEAD_i == 0) begin 
            if (!Ss && (ssCnt <= ssNum+LAG_i+LEAD_i && ssCnt > LAG_i) ) begin 
                Sck_o = ~(~Clk_i);
            end
            else begin 
                Sck_o = 1'b0;
                end
            end
            else begin 
                if (!Ss && (ssCnt < ssNum+LAG_i+LEAD_i && ssCnt > LAG_i)) begin 
                    Sck_o = ~(~Clk_i);
                end
                else begin 
                    Sck_o = 1'b0;
                end
            end
        end
        else begin
            if (LEAD_i == 0) begin 
                if (!Ss && (ssCnt <= ssNum+LAG_i+LEAD_i && ssCnt > LAG_i) ) begin 
                    Sck_o = ~(Clk_i);
                end
                else begin 
                    Sck_o = 1'b0;
                end
            end
            else begin 
                if (!Ss && (ssCnt < ssNum + LAG_i + LEAD_i && ssCnt > LAG_i)) begin 
                    Sck_o = ~(Clk_i);
                end
                else begin 
                    Sck_o = 1'b0;
                end
            end
        end
    end
    else begin 
        if (CPHA_i) begin
            if (LEAD_i == 0) begin  
                if (!Ss && (ssCnt <= ssNum+LAG_i+LEAD_i && ssCnt > LAG_i) ) begin 
                    Sck_o = ~(Clk_i);
                end
                else begin 
                    Sck_o = 1'b0;
                end
            end
            else begin 
                if (!Ss && (ssCnt <ssNum + LAG_i + LAG_i && ssCnt > LAG_i)) begin 
                    Sck_o = ~(Clk_i);
                end
                else begin 
                    Sck_o = 1'b0;
                end
            end
        end 
        else begin
            if (LEAD_i == 0) begin 
                if (!Ss && (ssCnt <= ssNum+LAG_i+LEAD_i && ssCnt > LAG_i) ) begin 
                    Sck_o = ~(~Clk_i);
                end
                else begin 
                    Sck_o = 1'b0;
                end
            end
            else begin 
                if (!Ss && (ssCnt < ssNum + LAG_i + LEAD_i && ssCnt > LAG_i)) begin 
                    Sck_o = ~(~Clk_i);
                end
                else begin 
                    Sck_o = 1'b0;
                end
            end
        end
    end
end


always @(*) begin
    if (EndianSel_i) begin 
        case (WidthSel_i) 
            0 : begin 
                Mosi0_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i) ) ? (mosiReg3[1]):1'b0;
                Mosi1_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg2[1]):1'b0;
                Mosi2_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg1[1]):1'b0;
                Mosi3_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg0[1]):1'b0;
            end
            1 : begin 
                Mosi0_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg3[3]):1'b0;
                Mosi1_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg2[3]):1'b0;
                Mosi2_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg1[3]):1'b0;
                Mosi3_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg0[3]):1'b0;
            end
            2 : begin 
                Mosi0_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg3[5]):1'b0;
                Mosi1_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg2[5]):1'b0;
                Mosi2_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg1[5]):1'b0;
                Mosi3_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg0[5]):1'b0;
            end
            3 : begin 
                Mosi0_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg3[7]):1'b0;
                Mosi1_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg2[7]):1'b0;
                Mosi2_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg1[7]):1'b0;
                Mosi3_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i)) ? (mosiReg0[7]):1'b0;
            end
        endcase
    end
    else begin 
        case (WidthSel_i)
            0 : begin
                Mosi0_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[1]):1'b0;
                Mosi1_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg1[1]):1'b0;
                Mosi2_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg2[1]):1'b0;
                Mosi3_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg3[1]):1'b0;
            end
            1 : begin
                Mosi0_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[3]):1'b0;
                Mosi1_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg1[3]):1'b0;
                Mosi2_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg2[3]):1'b0;
                Mosi3_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt >LAG_i))? (mosiReg3[3]):1'b0;
            end
            2 : begin
                Mosi0_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[5]):1'b0;
                Mosi1_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg1[5]):1'b0;
                Mosi2_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg2[5]):1'b0;
                Mosi3_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg3[5]):1'b0;
            end
            3 : begin
                Mosi0_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[7]):1'b0;
                Mosi1_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg1[7]):1'b0;
                Mosi2_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg2[7]):1'b0;
                Mosi3_i = (!Ss&& (ssCnt < ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg3[7]):1'b0;
            end
        endcase
    end
end


always @(posedge Clk_i) begin
    if (Rst_i) begin
        SSr <=1'b0;
    end
    else begin 
        SSr <= Ss;
    end
end


always @(*) begin
    if (SELST_i) begin 
        if (Ss && !SSr) begin 
            Val_o = 1'b1;
        end
        else begin 
            Val_o = 1'b0;
        end
    end
    else begin 
        if (!Ss&& SSr) begin 
            Val_o = 1'b1;
        end
        else begin 
            Val_o = 1'b0;
        end
    end
end



always @(*) begin 
    if (Rst_i) begin 
        startFlag = 1'b0;
    end
    else begin 
        if (Start_i&& !stopFlag) begin 
            startFlag = 1'b1;
        end
        else begin 
            startFlag = 1'b0;
        end
    end
end

always @(*) begin 
    if (Rst_i) begin 
        ssNum = 1'b0;
    end
    else begin 
        case (WidthSel_i) 
            0 : begin 
                ssNum = 2;
            end
            1 : begin 
                ssNum = 4;
            end
            2 : begin 
                ssNum = 6;
            end
            3 : begin 
                ssNum = 8;
            end
        endcase
    end
end


always @(negedge Clk_i) begin 
    if (Rst_i) begin 
        ssCnt <= 1'b0;
    end
    else if (ssCnt < (ssNum+LAG_i+LEAD_i)  && startFlag  ) begin 
        ssCnt <= ssCnt + 1'b1;
    end
    else begin
        if (ssCnt == ssNum-1 || !startFlag) begin 
            ssCnt <= 1'b0;
        end
    end
end




always @(negedge Clk_i) begin 
    if (Rst_i) begin 
        Ss <= 1'b1;
    end
    else begin 
        if (ssCnt < (ssNum+LAG_i+LEAD_i)  && startFlag ) begin 
            Ss <= 1'b0;
        end
        else begin 
            Ss <= 1'b1;
        end
    end
end


always @(negedge Clk_i) begin 
    if (Rst_i) begin 
        mosiReg0 <= SPIdata[31:24];
    end
    else begin 
        if (!SSr && (ssCnt > LAG_i && ssCnt < ssNum + LAG_i + LEAD_i)) begin
            mosiReg0 <= { mosiReg0[6:0],1'b0 };
        end
        else begin 
            mosiReg0 <= SPIdata[31:24];
        end
    end
end

always @(negedge Clk_i) begin 
    if (Rst_i) begin 
        mosiReg1 <= SPIdata[23:16];
    end
    else begin 
        if (!SSr&& (ssCnt > LAG_i && ssCnt < ssNum + LAG_i + LEAD_i)) begin
            mosiReg1 <= { mosiReg1[6:0],1'b0 };
        end
        else begin 
            mosiReg1 <= SPIdata[23:16];
        end
    end
end

always @(negedge Clk_i) begin 
    if (Rst_i) begin 
        mosiReg2 <= SPIdata[15:8];
    end
    else begin 
        if (!SSr&& (ssCnt > LAG_i && ssCnt < ssNum + LAG_i + LEAD_i)) begin
            mosiReg2 <= { mosiReg2[6:0],1'b0 };
        end
        else begin 
            mosiReg2 <= SPIdata[15:8];
        end
    end
end

always @(negedge Clk_i) begin 
    if (Rst_i) begin 
        mosiReg3 <= SPIdata[7:0];
    end
    else begin 
        if (!SSr&& (ssCnt > LAG_i && ssCnt < ssNum + LAG_i + LEAD_i)) begin
            mosiReg3 <= { mosiReg3[6:0],1'b0 };
        end
        else begin 
            mosiReg3 <= SPIdata[7:0];
        end
    end
end













endmodule