AXI_Slave 代码心得体会

	// Implement memory mapped register select and read logic generation
	// Slave register read enable is asserted when valid address is available
	// and the slave is ready to accept the read address.
	assign slv_reg_rden = axi_arready & S_AXI_ARVALID & ~axi_rvalid;
	always @(*)
	begin
	      // Address decoding for reading registers
	      case ( axi_araddr[ADDR_LSB+OPT_MEM_ADDR_BITS:ADDR_LSB] )
	        2'h0   : reg_data_out <= slv_reg0;
	        2'h1   : reg_data_out <= slv_reg1;
	        2'h2   : reg_data_out <= slv_reg2;
	        2'h3   : reg_data_out <= slv_reg3;
	        default : reg_data_out <= 0;
	      endcase
	end

	// Output register or memory read data
	always @( posedge S_AXI_ACLK )
	begin
	  if ( S_AXI_ARESETN == 1'b0 )
	    begin
	      axi_rdata  <= 0;
	    end 
	  else
	    begin    
	      // When there is a valid read address (S_AXI_ARVALID) with 
	      // acceptance of read address by the slave (axi_arready), 
	      // output the read dada 
	      if (slv_reg_rden)
	        begin
	          axi_rdata <= reg_data_out;     // register read data
	        end   
	    end
	end 

实际可参考，地址使用组合逻辑，其它使用时序逻辑