AXI_SLAVER代码问题求助！！！

求问各位大佬，为什么这里在1处对arlen等信号赋值是赋不上值的？？？但axi_arready却可以赋值上，这是为什么，怎么解决这个问题呢！

如果使用2则会延后一拍，但这不是想要的效果。

//-------------------------------------------------------------------------------- // axi_slv //-------------------------------------------------------------------------------- `include "axi_define.v" module axi_slv ( // system signals input wire axi_aclk , input wire axi_arst_n , // AXI rd addr channel output reg axi_arready, input wire axi_arvalid, input wire [`AXI_ID_WIDTH -1:0] axi_arid , input wire [`AXI_ADDR_WIDTH -1:0] axi_araddr , input wire [`AXI_LEN_WIDTH -1:0] axi_arlen , input wire [`AXI_SIZE_WIDTH -1:0] axi_arsize , input wire [`AXI_BURST_WIDTH -1:0] axi_arburst, input wire axi_arlock , input wire [`AXI_CACHE_WIDTH -1:0] axi_arcache, input wire [`AXI_PROT_WIDTH -1:0] axi_arprot , input wire [`AXI_QOS_WIDTH -1:0] axi_arqos , // AXI rd data channel input wire axi_rready , output reg axi_rvalid , output reg [`AXI_ID_WIDTH -1:0] axi_rid , output reg [`AXI_DATA_WIDTH -1:0] axi_rdata , output wire [`AXI_RESP_WIDTH -1:0] axi_rresp , output wire axi_rlast , // User input wire enable ); //-------------------------------------------------------------------------------- // register and I/O //-------------------------------------------------------------------------------- reg [`AXI_ID_WIDTH -1:0] arid ; reg [`AXI_ADDR_WIDTH -1:0] araddr ; reg [`AXI_SIZE_WIDTH -1:0] arsize ; reg [`AXI_LEN_WIDTH -1:0] arlen ; reg [`AXI_BURST_WIDTH-1:0] arburst ; reg [`AXI_LEN_WIDTH -1:0] beat_cnt; reg [15:0] get_delay_cnt; reg [`AXI_DATA_WIDTH -1:0] data_mem [1023:0]; // Internal memory for data reg [5:0] curr_state, next_state; // Burst and resp type localparam AXI_BURST_FIXED = 2'b00; localparam AXI_BURST_INCR = 2'b01; localparam AXI_BURST_WRAP = 2'b10; localparam AXI_RESP_OKAY = 2'b00; localparam AXI_RESP_SLVERR = 2'b10; localparam AXI_RESP_DECERR = 2'b11; // Unified read/write FSM localparam ST_IDLE = 6'b00_0000; localparam ST_AR_HANDSHAKE = 6'b00_0001; localparam ST_R_HANDSHAKE = 6'b00_0010; // Loading data initial begin $readmemh("sine_wave.mem", data_mem); end assign axi_rlast = (axi_rvalid && axi_rready && (beat_cnt == arlen)) ? 1'b1 : 1'b0; assign axi_rresp = `AXI_RESP_OKAY; //-------------------------------------------------------------------------------- // FSM //-------------------------------------------------------------------------------- always @(posedge axi_aclk or negedge axi_arst_n) begin if (!axi_arst_n) begin curr_state <= ST_IDLE; end else begin curr_state <= next_state; end end always @(*) begin next_state = curr_state; case (curr_state) ST_IDLE:begin if (enable) begin next_state = ST_AR_HANDSHAKE; end else begin next_state = ST_IDLE; end end ST_AR_HANDSHAKE:begin if (axi_arvalid && axi_arready) begin next_state = ST_R_HANDSHAKE; end else begin next_state = ST_AR_HANDSHAKE; end end ST_R_HANDSHAKE:begin if (axi_rvalid && axi_rready && axi_rlast) begin next_state = ST_IDLE; end else begin next_state = ST_R_HANDSHAKE; end end default:begin next_state = ST_IDLE; end endcase end always @(posedge axi_aclk or negedge axi_arst_n) begin if (!axi_arst_n) begin axi_arready <= 1'b0; axi_rvalid <= 1'b0; axi_rid <= `AXI_ID_WIDTH'h0; axi_rdata <= `AXI_DATA_WIDTH'h0; araddr <= `AXI_ADDR_WIDTH'h0; arsize <= `AXI_SIZE_WIDTH'h0; arlen <= `AXI_LEN_WIDTH'h0 ; arburst <= `AXI_BURST_WIDTH'h0; beat_cnt <= `AXI_LEN_WIDTH'd0 ; get_delay_cnt <= 16'd0; end else begin case (curr_state) ST_IDLE:begin axi_arready <= 1'b0; axi_rvalid <= 1'b0; axi_rid <= `AXI_ID_WIDTH'h0; axi_rdata <= `AXI_DATA_WIDTH'h0; araddr <= `AXI_ADDR_WIDTH'h0; arsize <= `AXI_SIZE_WIDTH'h0; arlen <= `AXI_LEN_WIDTH'h0 ; arburst <= `AXI_BURST_WIDTH'h0; beat_cnt <= `AXI_LEN_WIDTH'd0 ; get_delay_cnt <= 16'd0; end ST_AR_HANDSHAKE:begin if (axi_arvalid && !axi_arready) begin axi_arready <= 1'b1; end else if (axi_arvalid && axi_arready) begin axi_arready <= 1'b0; // axi_rid <= axi_arid ; // araddr <= axi_araddr ; // arsize <= axi_arsize ; // arlen <= axi_arlen ; // arburst <= axi_arburst; end end ST_R_HANDSHAKE:begin araddr <= axi_araddr ; arsize <= axi_arsize ; arlen <= axi_arlen ; arburst <= axi_arburst; if (!axi_rvalid && !axi_rready) begin if (get_delay_cnt == `DATA_GET_DELAY) begin axi_rvalid <= 1'b1; get_delay_cnt <= 16'd0; end else begin axi_rvalid <= 1'b0; get_delay_cnt <= get_delay_cnt + 1'b1; end end else if (axi_rvalid && axi_rready) begin axi_rvalid <= 1'b0; axi_rid <= axi_arid ; axi_rdata <= data_mem[curr_addr]; beat_cnt <= beat_cnt + 1; curr_addr <= curr_addr + 1; end end default: ; endcase end end endmodule