valid/ready握手机制及verilog代码
valid/ready握手协议
在两个模块之间传输数据时候，可以使用valid/ready握手协议，保证数据传输的有效性。
发送方准备发送数据时，它发送valid信号给接收方，接收方准备好可以接收数据时候，他发送ready信号给发送方，在valid和ready信号都置高的时钟上升沿，开始传送数据。
valid/ready状态机
发送方接收方都会处于下图所示四个状态之一，它们的状态转化图如下
verilog实现代码
发送模块，文件名称：transmitter.sv
`timescale 1ns/1ns
module transmitter #(parameter DATA_WIDTH=8)
(
input wire clk,
input wire rst_n,
output logic vld,
output logic [DATA_WIDTH-1:0] data,
input wire rdy
);
//下一个valid信号
logic next_vld;
//下一个数据及hold的数据
logic [DATA_WIDTH-1:0] next_data;
reg [DATA_WIDTH-1:0] hold_data;
//内部valid信号
logic i_vld;
//内部data信号
logic [DATA_WIDTH-1:0] i_data;
//发送数据队列，记录发送的数据，便于debug显示
logic [DATA_WIDTH-1:0] sent_data[$];
typedef enum {IDLE, WAIT_RDY, WAIT_VLD, TRANSFER} ff_state;
ff_state current_state = IDLE;
ff_state next_state = IDLE;
//根据现在状态，更新下一个状态
always_comb begin
case (current_state)
IDLE: begin
if (i_vld == 1 && rdy == 0) begin
next_state = WAIT_RDY;
end else if (i_vld == 0 && rdy == 1) begin
next_state = WAIT_VLD;
end else if (i_vld == 1 && rdy == 1) begin
next_state = TRANSFER;
end else begin
next_state = current_state;
end
end
WAIT_RDY: begin
if (i_vld == 1 && rdy == 1) begin
next_state = TRANSFER;
end else begin
next_state = current_state;
end
end
WAIT_VLD: begin
if (i_vld == 1 && rdy == 1) begin
next_state = TRANSFER;
end else begin
next_state = current_state;
end
end
TRANSFER: begin
if (i_vld == 1 && rdy == 0) begin
next_state = WAIT_RDY;
end else if (i_vld == 0 && rdy == 1) begin
next_state = WAIT_VLD;
end else if (i_vld == 0 && rdy == 0) begin
next_state = IDLE;
end else begin
next_state = current_state;
end
end
endcase
end
always_ff @(posedge clk or negedge rst_n) begin
// Next state here is the previous state from the previous cycle
$display("[DEBUG %d] next_vld: %d, next_state: %d, current_state: %d", $time, next_vld, next_state, current_state);
if (!rst_n) begin
current_state <= IDLE;
i_vld <= 0;
i_data <= 0;
end else begin
current_state <= next_state;
//随机赋值下一个valid信号
next_vld = $urandom;
if (next_vld == 1 && next_state != WAIT_RDY) begin
//在下一个时钟周期发送下一个数据，这儿是准备下一个数据
//下一个数据时1-10之间的随机值
next_data = $urandom_range(1,10);
//保持数据等于下一个数据
hold_data = next_data;
//把下一个数据放进发送队列
sent_data.push_back(next_data);
end else if (next_state == WAIT_RDY) begin
next_data = hold_data;
end else begin
next_data = 0;
end
//更新内部信号
i_vld <= #0.1 (next_state == WAIT_RDY) ? 1 : next_vld;
i_data <= #0.1 next_data;
end
end
//更新接口信号
assign vld = i_vld;
assign data = i_data;
endmodule
接收模块，文件名称:receiver.sv
`timescale 1ns/1ns
module receiver #(parameter DATA_WIDTH=8)
(
input wire clk,
input wire rst_n,
input wire vld,
input wire [DATA_WIDTH-1:0] data,
output logic rdy
);
logic next_rdy;
//内部ready信号
logic i_rdy;
//接收数据队列
logic [DATA_WIDTH-1:0] received_data[$];
logic no_random = 0;
typedef enum {IDLE, WAIT_RDY, WAIT_VLD, TRANSFER} ff_state;
ff_state current_state = IDLE;
ff_state next_state = IDLE;
//状态机更新
always_comb begin
case (current_state)
IDLE: begin
no_random = 0;
if (i_rdy == 1 && vld == 0) begin
next_state = WAIT_VLD;
end else if (i_rdy == 0 && vld == 1) begin
next_state = WAIT_RDY;
end else if (i_rdy == 1 && vld == 1) begin
next_state = TRANSFER;
end else begin
next_state = current_state;
end
end
WAIT_VLD: begin
no_random = 1;
if (i_rdy == 1 && vld == 1) begin
next_state = TRANSFER;
end else begin
next_state = current_state;
end
end
WAIT_RDY: begin
no_random = 0;
if (i_rdy == 1 && vld == 1) begin
next_state = TRANSFER;
end else begin
next_state = current_state;
end
end
TRANSFER: begin
if (i_rdy == 1 && vld == 0) begin
next_state = WAIT_VLD;
end else if (i_rdy == 0 && vld == 1) begin
next_state = WAIT_RDY;
end else if (i_rdy == 0 && vld == 0) begin
next_state = IDLE;
end else begin
next_state = current_state;
end
end
endcase
end
always_ff @(posedge clk or negedge rst_n) begin
$display("[DEBUG %d] current data: %d, current_state: %d, next_state: %d", $time, data, current_state, next_state);
//把接收的数据放入接收队列，以便debug显示
if (next_state == TRANSFER) begin
// Sample the data
$display("[DEBUG %0t] pushing %d data value", $time, data);
received_data.push_back(data);
end
if (!rst_n) begin
i_rdy <= 0;
current_state <= #0.1 IDLE;
end else begin
//更新内部ready信号
i_rdy <= #0.1 (next_state == WAIT_VLD) ? 1 : $urandom;
current_state <= #0.1 next_state;
end
end
assign rdy = i_rdy;
endmodule
testbench文件名称:valid_ready.tb
`timescale 1ns/1ns
module test_top;
reg _clk;
reg _rst_n;
wire [7:0] _data;
wire _vld;
wire _rdy;
initial begin
$display("start a clock pulse");
$dumpfile("valid_ready.vcd");
$dumpvars(0, test_top);
//#1000 $finish;
end
transmitter tx(_clk, _rst_n, _vld, _data, _rdy);
receiver rx(_clk, _rst_n, _vld, _data, _rdy);
initial begin
_clk = 0;
_rst_n = 1;
#10;
_rst_n = 0;
#10;
_rst_n = 1;
#1000;
foreach (rx.received_data[i]) begin
$display("[DEBUG] RX RECEIVED %d: %d", i, rx.received_data[i]);
end
foreach (tx.sent_data[i]) begin
$display("[DEBUG] TX SENT %d: %d", i, tx.sent_data[i]);
end
$finish;
end
always #5ns _clk = ~_clk;
endmodule
波形文件
由于iverilog不支持一些systemverilog语法，我们在modelsim中建立工程，导入上述三个文件。运行仿真后，得到如下波形:
状态IDLE=0,WAIT_RDY=1,WAIT_VLD=2,TRAMSFER=3
# start a clock pulse
# [DEBUG 5] current data: x, current_state: 0, next_state: 0
# [DEBUG 5] next_vld: x, next_state: 0, current_state: 0
# [DEBUG 10] current data: 0, current_state: 0, next_state: 0
# [DEBUG 10] next_vld: 0, next_state: 0, current_state: 0
# [DEBUG 15] current data: 0, current_state: 0, next_state: 0
# [DEBUG 15] next_vld: 0, next_state: 0, current_state: 0
# [DEBUG 25] current data: 0, current_state: 0, next_state: 0
# [DEBUG 25] next_vld: 0, next_state: 0, current_state: 0
# [DEBUG 35] current data: 0, current_state: 0, next_state: 0
# [DEBUG 35] next_vld: 0, next_state: 0, current_state: 0
# [DEBUG 45] current data: 0, current_state: 0, next_state: 0
# [DEBUG 45] next_vld: 0, next_state: 0, current_state: 0
# [DEBUG 55] current data: 0, current_state: 0, next_state: 0
# [DEBUG 55] next_vld: 0, next_state: 0, current_state: 0
# [DEBUG 65] current data: 0, current_state: 0, next_state: 2
# [DEBUG 65] next_vld: 0, next_state: 2, current_state: 0
# [DEBUG 75] current data: 6, current_state: 2, next_state: 3
# [DEBUG 75] pushing 6 data value
# [DEBUG 75] next_vld: 1, next_state: 3, current_state: 2
# [DEBUG 85] current data: 8, current_state: 3, next_state: 1
# [DEBUG 85] next_vld: 1, next_state: 1, current_state: 3
# [DEBUG 95] current data: 8, current_state: 1, next_state: 1
# [DEBUG 95] next_vld: 0, next_state: 1, current_state: 1
# [DEBUG 105] current data: 8, current_state: 1, next_state: 3
# [DEBUG 105] pushing 8 data value
# [DEBUG 105] next_vld: 1, next_state: 3, current_state: 1
# [DEBUG 115] current data: 7, current_state: 3, next_state: 3
# [DEBUG 115] pushing 7 data value
# [DEBUG 115] next_vld: 1, next_state: 3, current_state: 3
# [DEBUG 125] current data: 0, current_state: 3, next_state: 2
# [DEBUG 125] next_vld: 0, next_state: 2, current_state: 3
# [DEBUG 135] current data: 0, current_state: 2, next_state: 2
# [DEBUG 135] next_vld: 0, next_state: 2, current_state: 2
# [DEBUG 145] current data: 0, current_state: 2, next_state: 2
# [DEBUG 145] next_vld: 0, next_state: 2, current_state: 2
# [DEBUG 155] current data: 8, current_state: 2, next_state: 3
# [DEBUG 155] pushing 8 data value
# [DEBUG 155] next_vld: 1, next_state: 3, current_state: 2
# [DEBUG 165] current data: 9, current_state: 3, next_state: 3
# [DEBUG 165] pushing 9 data value
# [DEBUG 165] next_vld: 1, next_state: 3, current_state: 3
# [DEBUG 175] current data: 10, current_state: 3, next_state: 1
# [DEBUG 175] next_vld: 1, next_state: 1, current_state: 3
# [DEBUG 185] current data: 10, current_state: 1, next_state: 1
# [DEBUG 185] next_vld: 1, next_state: 1, current_state: 1
# [DEBUG 195] current data: 10, current_state: 1, next_state: 3
# [DEBUG 195] pushing 10 data value
# [DEBUG 195] next_vld: 0, next_state: 3, current_state: 1
# [DEBUG 205] current data: 7, current_state: 3, next_state: 1
# [DEBUG 205] next_vld: 1, next_state: 1, current_state: 3
# [DEBUG 215] current data: 7, current_state: 1, next_state: 3
# [DEBUG 215] pushing 7 data value
# [DEBUG 215] next_vld: 0, next_state: 3, current_state: 1
# [DEBUG 225] current data: 5, current_state: 3, next_state: 3
# [DEBUG 225] pushing 5 data value
# [DEBUG 225] next_vld: 1, next_state: 3, current_state: 3
# [DEBUG 235] current data: 0, current_state: 3, next_state: 0
# [DEBUG 235] next_vld: 0, next_state: 0, current_state: 3
# [DEBUG 245] current data: 0, current_state: 0, next_state: 0
# [DEBUG 245] next_vld: 0, next_state: 0, current_state: 0
# [DEBUG 255] current data: 0, current_state: 0, next_state: 2
# [DEBUG 255] next_vld: 0, next_state: 2, current_state: 0
# [DEBUG 265] current data: 9, current_state: 2, next_state: 3
# [DEBUG 265] pushing 9 data value
# [DEBUG 265] next_vld: 1, next_state: 3, current_state: 2
# [DEBUG 275] current data: 2, current_state: 3, next_state: 3
# [DEBUG 275] pushing 2 data value
# [DEBUG 275] next_vld: 1, next_state: 3, current_state: 3
# [DEBUG 285] current data: 9, current_state: 3, next_state: 1
# [DEBUG 285] next_vld: 1, next_state: 1, current_state: 3
# [DEBUG 295] current data: 9, current_state: 1, next_state: 1
# [DEBUG 295] next_vld: 1, next_state: 1, current_state: 1
# [DEBUG 305] current data: 9, current_state: 1, next_state: 3
# [DEBUG 305] pushing 9 data value
# [DEBUG 305] next_vld: 1, next_state: 3, current_state: 1
# [DEBUG 315] current data: 0, current_state: 3, next_state: 0
# [DEBUG 315] next_vld: 0, next_state: 0, current_state: 3
# [DEBUG 325] current data: 2, current_state: 0, next_state: 3
# [DEBUG 325] pushing 2 data value
# [DEBUG 325] next_vld: 1, next_state: 3, current_state: 0
# [DEBUG 335] current data: 1, current_state: 3, next_state: 1
# [DEBUG 335] next_vld: 1, next_state: 1, current_state: 3
# [DEBUG 345] current data: 1, current_state: 1, next_state: 3
# [DEBUG 345] pushing 1 data value
# [DEBUG 345] next_vld: 0, next_state: 3, current_state: 1
# [DEBUG 355] current data: 2, current_state: 3, next_state: 3
# [DEBUG 355] pushing 2 data value
# [DEBUG 355] next_vld: 1, next_state: 3, current_state: 3
# [DEBUG 365] current data: 0, current_state: 3, next_state: 0
# [DEBUG 365] next_vld: 0, next_state: 0, current_state: 3
# [DEBUG 375] current data: 0, current_state: 0, next_state: 2
# [DEBUG 375] next_vld: 0, next_state: 2, current_state: 0
# [DEBUG 385] current data: 0, current_state: 2, next_state: 2
# [DEBUG 385] next_vld: 0, next_state: 2, current_state: 2
# [DEBUG 395] current data: 10, current_state: 2, next_state: 3
# [DEBUG 395] pushing 10 data value
# [DEBUG 395] next_vld: 1, next_state: 3, current_state: 2
# [DEBUG 405] current data: 0, current_state: 3, next_state: 0
# [DEBUG 405] next_vld: 0, next_state: 0, current_state: 3
# [DEBUG 415] current data: 0, current_state: 0, next_state: 2
# [DEBUG 415] next_vld: 0, next_state: 2, current_state: 0
# [DEBUG 425] current data: 0, current_state: 2, next_state: 2
# [DEBUG 425] next_vld: 0, next_state: 2, current_state: 2
# [DEBUG 435] current data: 8, current_state: 2, next_state: 3
# [DEBUG 435] pushing 8 data value
# [DEBUG 435] next_vld: 1, next_state: 3, current_state: 2
# [DEBUG 445] current data: 6, current_state: 3, next_state: 1
# [DEBUG 445] next_vld: 1, next_state: 1, current_state: 3
# [DEBUG 455] current data: 6, current_state: 1, next_state: 1
# [DEBUG 455] next_vld: 0, next_state: 1, current_state: 1
# [DEBUG 465] current data: 6, current_state: 1, next_state: 3
# [DEBUG 465] pushing 6 data value
# [DEBUG 465] next_vld: 0, next_state: 3, current_state: 1
# [DEBUG 475] current data: 7, current_state: 3, next_state: 1
# [DEBUG 475] next_vld: 1, next_state: 1, current_state: 3
# [DEBUG 485] current data: 7, current_state: 1, next_state: 1
# [DEBUG 485] next_vld: 0, next_state: 1, current_state: 1
# [DEBUG 495] current data: 7, current_state: 1, next_state: 1
# [DEBUG 495] next_vld: 0, next_state: 1, current_state: 1
# [DEBUG 505] current data: 7, current_state: 1, next_state: 3
# [DEBUG 505] pushing 7 data value
# [DEBUG 505] next_vld: 0, next_state: 3, current_state: 1
# [DEBUG 515] current data: 7, current_state: 3, next_state: 3
# [DEBUG 515] pushing 7 data value
# [DEBUG 515] next_vld: 1, next_state: 3, current_state: 3
# [DEBUG 525] current data: 10, current_state: 3, next_state: 3
# [DEBUG 525] pushing 10 data value
# [DEBUG 525] next_vld: 1, next_state: 3, current_state: 3
# [DEBUG 535] current data: 0, current_state: 3, next_state: 0
# [DEBUG 535] next_vld: 0, next_state: 0, current_state: 3
# [DEBUG 545] current data: 7, current_state: 0, next_state: 3
# [DEBUG 545] pushing 7 data value
# [DEBUG 545] next_vld: 1, next_state: 3, current_state: 0
# [DEBUG 555] current data: 0, current_state: 3, next_state: 0
# [DEBUG 555] next_vld: 0, next_state: 0, current_state: 3
# [DEBUG 565] current data: 0, current_state: 0, next_state: 2
# [DEBUG 565] next_vld: 0, next_state: 2, current_state: 0
# [DEBUG 575] current data: 0, current_state: 2, next_state: 2
# [DEBUG 575] next_vld: 0, next_state: 2, current_state: 2
# [DEBUG 585] current data: 0, current_state: 2, next_state: 2
# [DEBUG 585] next_vld: 0, next_state: 2, current_state: 2
# [DEBUG 595] current data: 5, current_state: 2, next_state: 3
# [DEBUG 595] pushing 5 data value
# [DEBUG 595] next_vld: 1, next_state: 3, current_state: 2
# [DEBUG 605] current data: 9, current_state: 3, next_state: 1
# [DEBUG 605] next_vld: 1, next_state: 1, current_state: 3
# [DEBUG 615] current data: 9, current_state: 1, next_state: 3
# [DEBUG 615] pushing 9 data value
# [DEBUG 615] next_vld: 0, next_state: 3, current_state: 1
# [DEBUG 625] current data: 0, current_state: 3, next_state: 0
# [DEBUG 625] next_vld: 0, next_state: 0, current_state: 3
# [DEBUG 635] current data: 0, current_state: 0, next_state: 0
# [DEBUG 635] next_vld: 0, next_state: 0, current_state: 0
# [DEBUG 645] current data: 1, current_state: 0, next_state: 1
# [DEBUG 645] next_vld: 1, next_state: 1, current_state: 0
# [DEBUG 655] current data: 1, current_state: 1, next_state: 1
# [DEBUG 655] next_vld: 1, next_state: 1, current_state: 1
# [DEBUG 665] current data: 1, current_state: 1, next_state: 3
# [DEBUG 665] pushing 1 data value
# [DEBUG 665] next_vld: 1, next_state: 3, current_state: 1
# [DEBUG 675] current data: 3, current_state: 3, next_state: 3
# [DEBUG 675] pushing 3 data value
# [DEBUG 675] next_vld: 1, next_state: 3, current_state: 3
# [DEBUG 685] current data: 0, current_state: 3, next_state: 2
# [DEBUG 685] next_vld: 0, next_state: 2, current_state: 3
# [DEBUG 695] current data: 0, current_state: 2, next_state: 2
# [DEBUG 695] next_vld: 0, next_state: 2, current_state: 2
# [DEBUG 705] current data: 4, current_state: 2, next_state: 3
# [DEBUG 705] pushing 4 data value
# [DEBUG 705] next_vld: 1, next_state: 3, current_state: 2
# [DEBUG 715] current data: 0, current_state: 3, next_state: 0
# [DEBUG 715] next_vld: 0, next_state: 0, current_state: 3
# [DEBUG 725] current data: 7, current_state: 0, next_state: 3
# [DEBUG 725] pushing 7 data value
# [DEBUG 725] next_vld: 1, next_state: 3, current_state: 0
# [DEBUG 735] current data: 0, current_state: 3, next_state: 0
# [DEBUG 735] next_vld: 0, next_state: 0, current_state: 3
# [DEBUG 745] current data: 6, current_state: 0, next_state: 3
# [DEBUG 745] pushing 6 data value
# [DEBUG 745] next_vld: 1, next_state: 3, current_state: 0
# [DEBUG 755] current data: 0, current_state: 3, next_state: 2
# [DEBUG 755] next_vld: 0, next_state: 2, current_state: 3
# [DEBUG 765] current data: 3, current_state: 2, next_state: 3
# [DEBUG 765] pushing 3 data value
# [DEBUG 765] next_vld: 1, next_state: 3, current_state: 2
# [DEBUG 775] current data: 0, current_state: 3, next_state: 0
# [DEBUG 775] next_vld: 0, next_state: 0, current_state: 3
# [DEBUG 785] current data: 0, current_state: 0, next_state: 2
# [DEBUG 785] next_vld: 0, next_state: 2, current_state: 0
# [DEBUG 795] current data: 0, current_state: 2, next_state: 2
# [DEBUG 795] next_vld: 0, next_state: 2, current_state: 2
# [DEBUG 805] current data: 8, current_state: 2, next_state: 3
# [DEBUG 805] pushing 8 data value
# [DEBUG 805] next_vld: 1, next_state: 3, current_state: 2
# [DEBUG 815] current data: 0, current_state: 3, next_state: 0
# [DEBUG 815] next_vld: 0, next_state: 0, current_state: 3
# [DEBUG 825] current data: 6, current_state: 0, next_state: 1
# [DEBUG 825] next_vld: 1, next_state: 1, current_state: 0
# [DEBUG 835] current data: 6, current_state: 1, next_state: 3
# [DEBUG 835] pushing 6 data value
# [DEBUG 835] next_vld: 0, next_state: 3, current_state: 1
# [DEBUG 845] current data: 9, current_state: 3, next_state: 3
# [DEBUG 845] pushing 9 data value
# [DEBUG 845] next_vld: 1, next_state: 3, current_state: 3
# [DEBUG 855] current data: 5, current_state: 3, next_state: 3
# [DEBUG 855] pushing 5 data value
# [DEBUG 855] next_vld: 1, next_state: 3, current_state: 3
# [DEBUG 865] current data: 7, current_state: 3, next_state: 3
# [DEBUG 865] pushing 7 data value
# [DEBUG 865] next_vld: 1, next_state: 3, current_state: 3
# [DEBUG 875] current data: 0, current_state: 3, next_state: 0
# [DEBUG 875] next_vld: 0, next_state: 0, current_state: 3
# [DEBUG 885] current data: 8, current_state: 0, next_state: 3
# [DEBUG 885] pushing 8 data value
# [DEBUG 885] next_vld: 1, next_state: 3, current_state: 0
# [DEBUG 895] current data: 0, current_state: 3, next_state: 2
# [DEBUG 895] next_vld: 0, next_state: 2, current_state: 3
# [DEBUG 905] current data: 7, current_state: 2, next_state: 3
# [DEBUG 905] pushing 7 data value
# [DEBUG 905] next_vld: 1, next_state: 3, current_state: 2
# [DEBUG 915] current data: 10, current_state: 3, next_state: 1
# [DEBUG 915] next_vld: 1, next_state: 1, current_state: 3
# [DEBUG 925] current data: 10, current_state: 1, next_state: 1
# [DEBUG 925] next_vld: 1, next_state: 1, current_state: 1
# [DEBUG 935] current data: 10, current_state: 1, next_state: 1
# [DEBUG 935] next_vld: 0, next_state: 1, current_state: 1
# [DEBUG 945] current data: 10, current_state: 1, next_state: 1
# [DEBUG 945] next_vld: 0, next_state: 1, current_state: 1
# [DEBUG 955] current data: 10, current_state: 1, next_state: 1
# [DEBUG 955] next_vld: 0, next_state: 1, current_state: 1
# [DEBUG 965] current data: 10, current_state: 1, next_state: 3
# [DEBUG 965] pushing 10 data value
# [DEBUG 965] next_vld: 1, next_state: 3, current_state: 1
# [DEBUG 975] current data: 6, current_state: 3, next_state: 3
# [DEBUG 975] pushing 6 data value
# [DEBUG 975] next_vld: 1, next_state: 3, current_state: 3
# [DEBUG 985] current data: 0, current_state: 3, next_state: 0
# [DEBUG 985] next_vld: 0, next_state: 0, current_state: 3
# [DEBUG 995] current data: 3, current_state: 0, next_state: 1
# [DEBUG 995] next_vld: 1, next_state: 1, current_state: 0
# [DEBUG 1005] current data: 3, current_state: 1, next_state: 3
# [DEBUG 1005] pushing 3 data value
# [DEBUG 1005] next_vld: 1, next_state: 3, current_state: 1
# [DEBUG 1015] current data: 6, current_state: 3, next_state: 3
# [DEBUG 1015] pushing 6 data value
# [DEBUG 1015] next_vld: 1, next_state: 3, current_state: 3
# [DEBUG] RX RECEIVED 0: 6
# [DEBUG] RX RECEIVED 1: 8
# [DEBUG] RX RECEIVED 2: 7
# [DEBUG] RX RECEIVED 3: 8
# [DEBUG] RX RECEIVED 4: 9
# [DEBUG] RX RECEIVED 5: 10
# [DEBUG] RX RECEIVED 6: 7
# [DEBUG] RX RECEIVED 7: 5
# [DEBUG] RX RECEIVED 8: 9
# [DEBUG] RX RECEIVED 9: 2
# [DEBUG] RX RECEIVED 10: 9
# [DEBUG] RX RECEIVED 11: 2
# [DEBUG] RX RECEIVED 12: 1
# [DEBUG] RX RECEIVED 13: 2
# [DEBUG] RX RECEIVED 14: 10
# [DEBUG] RX RECEIVED 15: 8
# [DEBUG] RX RECEIVED 16: 6
# [DEBUG] RX RECEIVED 17: 7
# [DEBUG] RX RECEIVED 18: 7
# [DEBUG] RX RECEIVED 19: 10
# [DEBUG] RX RECEIVED 20: 7
# [DEBUG] RX RECEIVED 21: 5
# [DEBUG] RX RECEIVED 22: 9
# [DEBUG] RX RECEIVED 23: 1
# [DEBUG] RX RECEIVED 24: 3
# [DEBUG] RX RECEIVED 25: 4
# [DEBUG] RX RECEIVED 26: 7
# [DEBUG] RX RECEIVED 27: 6
# [DEBUG] RX RECEIVED 28: 3
# [DEBUG] RX RECEIVED 29: 8
# [DEBUG] RX RECEIVED 30: 6
# [DEBUG] RX RECEIVED 31: 9
# [DEBUG] RX RECEIVED 32: 5
# [DEBUG] RX RECEIVED 33: 7
# [DEBUG] RX RECEIVED 34: 8
# [DEBUG] RX RECEIVED 35: 7
# [DEBUG] RX RECEIVED 36: 10
# [DEBUG] RX RECEIVED 37: 6
# [DEBUG] RX RECEIVED 38: 3
# [DEBUG] RX RECEIVED 39: 6
# [DEBUG] TX SENT 0: 6
# [DEBUG] TX SENT 1: 8
# [DEBUG] TX SENT 2: 7
# [DEBUG] TX SENT 3: 8
# [DEBUG] TX SENT 4: 9
# [DEBUG] TX SENT 5: 10
# [DEBUG] TX SENT 6: 7
# [DEBUG] TX SENT 7: 5
# [DEBUG] TX SENT 8: 9
# [DEBUG] TX SENT 9: 2
# [DEBUG] TX SENT 10: 9
# [DEBUG] TX SENT 11: 2
# [DEBUG] TX SENT 12: 1
# [DEBUG] TX SENT 13: 2
# [DEBUG] TX SENT 14: 10
# [DEBUG] TX SENT 15: 8
# [DEBUG] TX SENT 16: 6
# [DEBUG] TX SENT 17: 7
# [DEBUG] TX SENT 18: 7
# [DEBUG] TX SENT 19: 10
# [DEBUG] TX SENT 20: 7
# [DEBUG] TX SENT 21: 5
# [DEBUG] TX SENT 22: 9
# [DEBUG] TX SENT 23: 1
# [DEBUG] TX SENT 24: 3
# [DEBUG] TX SENT 25: 4
# [DEBUG] TX SENT 26: 7
# [DEBUG] TX SENT 27: 6
# [DEBUG] TX SENT 28: 3
# [DEBUG] TX SENT 29: 8
# [DEBUG] TX SENT 30: 6
# [DEBUG] TX SENT 31: 9
# [DEBUG] TX SENT 32: 5
# [DEBUG] TX SENT 33: 7
# [DEBUG] TX SENT 34: 8
# [DEBUG] TX SENT 35: 7
# [DEBUG] TX SENT 36: 10
# [DEBUG] TX SENT 37: 6
# [DEBUG] TX SENT 38: 3
# [DEBUG] TX SENT 39: 6
# ** Note: $finish : D:/gkd/verilog/modelsim/valid_ready_tb.sv(45)
# Time: 1020 ns Iteration: 0 Instance: /test_top
# 1