module SPIm (
    input Clk_i,
    input Rst_i,
    input Start_i,
    input CPHA_i,
    input [31:0] SPIdata,
	input SpiDataVal_i,
    input SELST_i,
    input [1:0] WidthSel_i,
    input  LAG_i,
    input  LEAD_i,
    input EndianSel_i,
    input [5:0] Stop_i,
    input PulsePol_i,


    output reg Mosi0_o,
    output reg Sck_o,
    output  Ss_o,
    output  Val_o
);


//================================================================================
//	REG/WIRE
//================================================================================

reg startFlag;
reg startR;
reg [31:0] trCnt;
reg valReg;
reg valToRxFifo1;
reg lineBusy;
reg [5:0] ssCnt;
reg Ss;
reg [31:0]spiDataR;
reg oldDataFlag;

reg SSr;
reg SSR;
reg [31:0] mosiReg0;
reg [5:0] ssNum;
reg [2:0] delayCnt;
reg stopFlag;

wire SsPol = SELST_i ? Ss : ~Ss;


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


assign Ss_o = SsPol; 



assign Val_o = (trCnt < 1 ) ?!lineBusy:valReg;
//================================================================================
//	CODING
//================================================================================

always @(*) begin 
    if (SELST_i) begin 
        if (!Ss_o) begin 
            lineBusy = 1'b1;
        end
        else begin 
            lineBusy = 1'b0;
        end
    end
    else begin 
        if (Ss_o) begin 
            lineBusy = 1'b1;
        end
        else begin 
            lineBusy = 1'b0;
        end
    end
end



always @(posedge Clk_i) begin
    if (valReg) begin  
        spiDataR <= SPIdata;
    end
end


always @(*) begin 
    if (Rst_i) begin 
        oldDataFlag = 1'b0;
    end
    else begin 
        if (spiDataR == SPIdata) begin 
            oldDataFlag = 1'b1;
        end
        else begin 
            oldDataFlag = 1'b0;
        end
    end
end





always @(posedge Clk_i) begin 
    startR <= Start_i;
end

always @(*) begin 
    if (Rst_i) begin 
        valToRxFifo1 = 1'b0;
    end
    else begin 
        if (Start_i && !startR) begin 
            valToRxFifo1 = 1'b1;
        end
        else begin 
            valToRxFifo1 = 1'b0;
        end
    end
end

always @(posedge Clk_i) begin 
    if (Rst_i) begin 
        trCnt <= 1'b0;
    end
    else begin 
        if ( ssCnt == (ssNum + LEAD_i + LAG_i)) begin 
            trCnt <= trCnt + 1'b1;
        end
        else if (oldDataFlag) begin 
            trCnt <= 1'b0;
        end
    end
end




always @(negedge 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 (SsPol && !SSr) begin 
                stopFlag <= 1'b1;
            end
            else if ( delayCnt == Stop_i) begin 
                stopFlag <= 1'b0;
            end
        end
        else begin 
            if (!SsPol && SSr) begin 
                stopFlag <= 1'b1;
            end
            else if (delayCnt == Stop_i) begin 
                stopFlag <= 1'b0;
            end
        end
    end
end




always @(*) begin
    if (SELST_i) 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
    else begin 
          if (PulsePol_i) begin 
            if (CPHA_i) begin
                if (LEAD_i == 0) begin 
                if (SsPol && (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 (SsPol && (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 (SsPol && (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 (SsPol && (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 (SsPol && (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 (SsPol && (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 (SsPol && (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 (SsPol && (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
        
end


always @(*) begin
    if (Rst_i) begin 
        Mosi0_o = 1'b0;
    end
    else begin
        if (SELST_i) begin 
            if (!EndianSel_i) begin 
                case (WidthSel_i)  
                    0 : begin
                        Mosi0_o = (!Ss&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[7]):1'b0;
                    end
                    1 : begin
                        Mosi0_o = (!Ss&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[15]):1'b0;
                    end
                    2 : begin
                        Mosi0_o = (!Ss&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[23]):1'b0;
                    end
                    3 : begin
                        Mosi0_o = (!Ss&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[31]):1'b0;
                    end
                endcase
            end
            else begin 
                case (WidthSel_i)  
                    0 : begin
                        Mosi0_o = (!Ss&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[0]):1'b0;
                    end
                    1 : begin
                        Mosi0_o = (!Ss&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[0]):1'b0;
                    end
                    2 : begin
                        Mosi0_o = (!Ss&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[0]):1'b0;
                    end
                    3 : begin
                        Mosi0_o = (!Ss&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[0]):1'b0;
                    end
                endcase
            end
        end
        else begin 
            if (!EndianSel_i) begin 
                case (WidthSel_i)  
                    0 : begin
                        Mosi0_o = (SsPol&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[7]):1'b0;
                    end
                    1 : begin
                        Mosi0_o = (SsPol&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[15]):1'b0;
                    end
                    2 : begin
                        Mosi0_o = (SsPol&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[23]):1'b0;
                    end
                    3 : begin
                        Mosi0_o = (SsPol&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[31]):1'b0;
                    end
                endcase
            end
            else begin 
                case (WidthSel_i)  
                    0 : begin
                        Mosi0_o = (SsPol&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[0]):1'b0;
                    end
                    1 : begin
                        Mosi0_o = (SsPol&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[0]):1'b0;
                    end
                    2 : begin
                        Mosi0_o = (SsPol&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[0]):1'b0;
                    end
                    3 : begin
                        Mosi0_o = (SsPol&& (ssCnt <= ssNum+LAG_i && ssCnt > LAG_i))? (mosiReg0[0]):1'b0;
                    end
                endcase
            end
        end
    end
end



always @(posedge Clk_i) begin
    SSr <= SsPol;
    SSR <= Ss;
end


always @(*) begin 
    if (Rst_i) begin 
        startFlag = 1'b0;
    end
    else begin 
        if (Start_i&& !stopFlag && SPIdata != 0 && !oldDataFlag ) begin 
            startFlag = 1'b1;
        end
        else begin 
            startFlag = 1'b0;
        end
    end
end

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


always @(*) begin 
    if (Rst_i) begin 
        ssNum = 1'b0;
    end
    else begin 
        case (WidthSel_i) 
            0 : begin 
                ssNum = 8;
            end
            1 : begin 
                ssNum = 16;
            end
            2 : begin 
                ssNum = 24;
            end
            3 : begin 
                ssNum = 32;
            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[31:0];
    end
    else begin
        if (!EndianSel_i) begin 
            if (!SSR && (ssCnt > LAG_i && ssCnt < ssNum + LAG_i + LEAD_i)) begin
                mosiReg0 <= mosiReg0 << 1;
            end
            else begin 
                mosiReg0 <= SPIdata[31:0];
            end
        end
        else begin 
            if (!SSR && (ssCnt > LAG_i && ssCnt < ssNum + LAG_i + LEAD_i)) begin
                mosiReg0 <= mosiReg0 >> 1;
            end
            else begin 
                mosiReg0 <= SPIdata[31:0];
            end
        end
    end
end







endmodule