apb_transfer.v

AMBA2.0标准的AHB2APb桥

/*
传输控制模块,根据地址产生从设备选择信号
*/
module apb_transfer(
                    hclk,
                    hreset_n,
                    haddr_i,//[31:0],
                    pselx_en_i,
                    psel_slave_o

                    );
input hclk,
      hreset_n,
      pselx_en_i;//apb选择使能信号

input [31:0] haddr_i;

output [6:0]  psel_slave_o;
reg [6:0] psel_slave;

reg [31:0] pwdata_h;

wire psel_uart0_o,//选择uart0
     psel_uart1_o,//选择uart1
     psel_i2c_o,//选择i2c
     psel_ir_o,//选择中断模块（备选）
     psel_remap_o,
     psel_timer_o,//选择timer
     psel_pause_o;//选择中断模块（备选）
wire [31:0] haddr_i;

wire psel_uart0_en;
wire psel_uart1_en;
wire psel_i2c_en;
wire psel_ir_en;
wire psel_remap_en;
wire psel_timer_en;
wire psel_pause_en;

reg  psel_uart0,
     psel_uart1,
     psel_i2c,
     psel_ir,
     psel_remap,
     psel_timer,
     psel_pause;
wire [6:0] psel_slave_o;
parameter DELAY3 = 2'b11;



always @(  hreset_n or haddr_i )
  if (!hreset_n)
    begin
    psel_slave =  7'b0000_000;
    end
  else 
//  else if (pselx_en_i)
    
  case(haddr_i[31:12])
  20'HE000C:    
    begin
      psel_slave = 7'b000_0001;
    end
  20'HE0010:    
    begin
      psel_slave = 7'b000_0010;
    end
  20'HE001C:    
    begin
      psel_slave = 7'b000_0100;
    end
  20'HFFFFF:    
    begin
      psel_slave = 7'b000_1000;
    end
  20'HE002C:    
    begin
      psel_slave = 7'b001_0000;
    end
  20'HE003C:    
    begin
      psel_slave = 7'b010_0000;
    end
  20'HE004C:    
    begin
      psel_slave = 7'b100_0000;
    end
  default:
    begin
      psel_slave = 7'b000_0000;
    end
  endcase

assign psel_slave_o = psel_slave;



assign psel_uart0_o = (haddr_i[31:12]==20'HE000C)? 1'b1 : 1'b0;
assign psel_uart1_o = (haddr_i[31:12]==20'HE0010)? 1'b1 : 1'b0;
assign psel_i2c_o = (haddr_i[31:12]==20'HE001C)? 1'b1  : 1'b0;
assign psel_ir_o = (haddr_i[31:12]==20'HFFFFF)? 1'b1  : 1'b0;
assign psel_remap_o = (haddr_i[31:12]==20'HE002C)? 1'b1  : 1'b0;
assign psel_timer_o = (haddr_i[31:12]==20'HE003C)? 1'b1  : 1'b0;
assign psel_pause_o = (haddr_i[31:12]==20'HE004C)? 1'b1  : 1'b0;

endmodule