apb_controller.v

module apb_controller (input hclk,hresetn,hwrite_reg,hwrite,valid,
 input [31:0]haddr,hwdata,hwdata_1,hwdata_2,haddr1,haddr2,pr_data, 
 input [2:0] temp_selx, 
 output reg penable, pwrite, 
 output reg hr_readyout,
 output reg [2:0] psel, 
 output reg [31:0] paddr,pwdata);

reg penable_temp,pwrite_temp,hr_readyout_temp;
reg [2:0] psel_temp;
reg [31:0] paddr_temp,pwdata_temp;
parameter ST_IDLE=3'b000;
parameter ST_READ=3'b001;
parameter ST_RENABLE=3'b010;
parameter ST_WWAIT=3'b011;
parameter ST_WRITE=3'b100;
parameter ST_WRITEP=3'b101;
parameter ST_WENABLE=3'b110;
parameter ST_WENABLEP=3'b111;
reg [2:0] PS,NS;

always @(posedge hclk)
begin
   if (!hresetn)
      PS<=ST_IDLE;
   else
     PS<=NS;
end

always @(*)
begin
   NS=ST_IDLE;
   case(PS)
     ST_IDLE : 
          if(valid==1&&hwrite==1)
            NS=ST_WWAIT;
          else if(valid==1&&hwrite==0)
            NS=ST_READ;
          else if(valid==0)
           NS=ST_IDLE;

      ST_READ: NS=ST_RENABLE;

      ST_RENABLE: 
          if(valid==1&&hwrite==1)
            NS=ST_WWAIT;
          else if(valid==1&&hwrite==0)
            NS=ST_READ;
          else if(valid==0)
           NS=ST_IDLE;

      ST_WWAIT: 
         if (valid==1)
           NS=ST_WRITEP;
         else if(valid==0)
           NS=ST_WRITE;

      ST_WRITE:
         if (valid==1)
           NS=ST_WENABLEP;
         else if(valid==0)
           NS=ST_WENABLE;

      ST_WRITEP: NS=ST_WENABLEP;
      
      ST_WENABLEP:
          if (valid==1&&hwrite_reg==1)
           NS=ST_WRITEP;
         else if (valid==0&&hwrite_reg==1)
           NS=ST_WRITE;
         else if(hwrite_reg==0)
          NS=ST_READ;

      ST_WENABLE:
          if (valid==1 && hwrite==1)
            NS=ST_WWAIT;
          else if (valid==1 && hwrite==1)
            NS=ST_READ;
          else
            NS=ST_IDLE;
   endcase
end

always @(*)
begin
case(PS)

ST_IDLE: begin
          if(valid==1&&hwrite==0)
            begin
              paddr_temp=haddr;
              pwrite_temp=hwrite;
              psel_temp=temp_selx;
              penable_temp=0;
              hr_readyout_temp=0;
             end

          else if(valid==1&&hwrite==1)
            begin
               psel_temp=0;
               penable_temp=0;
               hr_readyout_temp=1;
            end    
        
          else
            begin
              psel_temp=0;
              penable_temp=0;
              hr_readyout_temp=1;
           end
         end
ST_READ: begin
              penable_temp=1;
              hr_readyout_temp=1;
         end

ST_RENABLE: begin
          if(valid==1&&hwrite==0)
            begin
              paddr_temp=haddr;
              pwrite_temp=hwrite;
              psel_temp=temp_selx;
              penable_temp=0;
              hr_readyout_temp=0;
             end

          else if(valid==1&&hwrite==1)
            begin
               psel_temp=0;
               penable_temp=0;
               hr_readyout_temp=1;
            end    
        
          else
            begin
              psel_temp=0;
              penable_temp=0;
              hr_readyout_temp=1;
           end
         end

ST_WWAIT:
	begin
             paddr_temp=haddr1;
             pwdata_temp=hwdata;
             pwrite_temp=hwrite;
             psel_temp=temp_selx;
             penable_temp=0;
             hr_readyout_temp=0;
          end
ST_WRITE:
	begin
             penable_temp=1;
             hr_readyout_temp=1;         
         end

ST_WRITEP:
         begin
             penable_temp=1;
             hr_readyout_temp=1;         
         end
ST_WENABLE:
         begin
           hr_readyout_temp=1; 
           penable_temp=0;
           psel_temp=0;
         end
ST_WENABLEP:
        begin
          paddr_temp=haddr2;
          hr_readyout_temp=0; 
          pwdata_temp=hwdata;    
          penable_temp=1;         
        end
endcase
end
always@(posedge hclk)
begin
   if(!hresetn)
     begin
        paddr<=0;
        pwdata<=0;
        pwrite<=0;
        psel<=0;
        penable<=0;
        hr_readyout<=1;
     end
   else begin
        paddr<=paddr_temp;
        pwdata<=pwdata_temp;
        pwrite<=pwrite_temp;
        psel<=psel_temp;
        penable<=penable_temp;
        hr_readyout<=hr_readyout_temp;
     end
end
endmodule