//24-6-26 姜青羊
//z-scan设计-output raster-scan order ID in z-scan order

module z_scan (
                    sob,
                    zid,
                    zid_vld,

                    clk,
                    rstn
                );

input  wire         sob;
input  wire         clk,rstn;

output reg          zid_vld;
output reg [5:0]    zid;

reg        [5:0]    ras_cnt;

always @(posedge clk or negedge rstn) begin
    if (~rstn) begin
        zid_vld <= 1'b0;
        ras_cnt <= 6'b000_000;
    end
    
    else if(sob) begin
        zid_vld <= 1'b0;
        ras_cnt <= 6'b111;    
    end
    else if(zid_vld) begin
        if(ras_cnt==6'b111_111)

        ras_cnt <= ras_cnt+6'b_1; 
    end
end

always @(sob or zid or zid_vld or ras_cnt ) begin
    case(ras_cnt) 
       6'd0: zid <= 6'd0;
       6'd1: zid <= 6'd1;
       6'd2: zid <= 6'd8;
       6'd3: zid <= 6'd9;
       6'd4: zid <= 6'd2;
       6'd5: zid <= 6'd3;
       6'd6: zid <= 6'd10;
       6'd7: zid <= 6'd11;
       6'd8: zid <= 6'd16;
       6'd9: zid <= 6'd17;
       6'd10: zid <= 6'd24;
       6'd11: zid <= 6'd25;
       6'd12: zid <= 6'd18;
       6'd13: zid <= 6'd19;
       6'd14: zid <= 6'd26;
       6'd15: zid <= 6'd27;
       6'd16: zid <= 6'd4;
       6'd17: zid <= 6'd5;
       6'd18: zid <= 6'd12;
       6'd19: zid <= 6'd13;
       6'd20: zid <= 6'd6;
       6'd21: zid <= 6'd7;
       6'd22: zid <= 6'd14;
       6'd23: zid <= 6'd15;
       6'd24: zid <= 6'd20;
       6'd25: zid <= 6'd21;
       6'd26: zid <= 6'd28;
       6'd27: zid <= 6'd29;
       6'd28: zid <= 6'd22;
       6'd29: zid <= 6'd23;
       6'd30: zid <= 6'd30;
       6'd31: zid <= 6'd31;
       6'd32: zid <= 6'd32;
       6'd33: zid <= 6'd33;
       6'd34: zid <= 6'd40;
       6'd35: zid <= 6'd41;
       6'd36: zid <= 6'd34;
       6'd37: zid <= 6'd35;
       6'd38: zid <= 6'd42;
       6'd39: zid <= 6'd43;
       6'd40: zid <= 6'd48;
       6'd41: zid <= 6'd49;
       6'd42: zid <= 6'd56;
       6'd43: zid <= 6'd57;
       6'd44: zid <= 6'd50;
       6'd45: zid <= 6'd51;
       6'd46: zid <= 6'd58;
       6'd47: zid <= 6'd59;
       6'd48: zid <= 6'd36;
       6'd49: zid <= 6'd37;
       6'd50: zid <= 6'd44;
       6'd51: zid <= 6'd45;
       6'd52: zid <= 6'd38;
       6'd53: zid <= 6'd39;
       6'd54: zid <= 6'd46;
       6'd55: zid <= 6'd47;
       6'd56: zid <= 6'd52;
       6'd57: zid <= 6'd53;
       6'd58: zid <= 6'd60;
       6'd59: zid <= 6'd61;
       6'd60: zid <= 6'd54;
       6'd61: zid <= 6'd55;
       6'd62: zid <= 6'd62;
       6'd63: zid <= 6'd63;
        
    endcase
end
    
endmodule