diff --git a/Labs/06. Main memory/tb_data_mem.sv b/Labs/06. Main memory/tb_data_mem.sv
new file mode 100644
index 0000000..184a430
--- /dev/null
+++ b/Labs/06. Main memory/tb_data_mem.sv	
@@ -0,0 +1,291 @@
+/* -----------------------------------------------------------------------------
+* Project Name   : Architectures of Processor Systems (APS) lab work
+* Organization   : National Research University of Electronic Technology (MIET)
+* Department     : Institute of Microdevices and Control Systems
+* Author(s)      : Andrei Solodovnikov
+* Email(s)       : hepoh@org.miet.ru
+
+See https://github.com/MPSU/APS/blob/master/LICENSE file for licensing details.
+* ------------------------------------------------------------------------------
+*/
+module tb_data_mem;
+  // Входы
+  import memory_pkg::DATA_MEM_SIZE_WORDS;
+  import memory_pkg::DATA_MEM_SIZE_BYTES;
+
+  logic        clk_i;
+  logic        mem_req_i;
+  logic        write_enable_i;
+  logic [3:0]  byte_enable_i;
+  logic [31:0] addr_i, addr;
+  logic [31:0] write_data_i;
+  assign addr = addr_i[2+:$clog2(DATA_MEM_SIZE_WORDS)];
+
+  logic [31:0] read_data_o;
+  logic        ready_o;
+
+
+  logic [31:0]  last_read_data;
+  logic [31:0]  last_write_data;
+
+  int err_cnt = 0;
+
+  static bit  simulation_finished;
+
+  data_mem DUT (.*);
+
+  task read_request(input logic [31:0] address, output logic [31:0] data);
+    addr_i          <= address;
+    mem_req_i       <= 1'b1;
+    write_enable_i  <= 1'b0;
+    @(posedge clk_i);
+    data = read_data_o;
+    mem_req_i       <= 1'b0;
+  endtask
+
+  task write_request( input logic [31:0] address, data, input [3:0] be);
+    addr_i          <= address;
+    mem_req_i       <= 1'b1;
+    write_enable_i  <= 1'b1;
+    byte_enable_i   <= be;
+    write_data_i    <= data;
+    @(posedge clk_i);
+    mem_req_i       <= 1'b0;
+  endtask
+
+  task direct_read_test();
+    logic [31:0] data;
+    for(int i = 0; i < 128; i++) begin
+      read_request(i, data);
+    end
+    if(DATA_MEM_SIZE_BYTES > 128) begin
+      for(int i = 1; i <= 128; i++) begin
+        read_request(DATA_MEM_SIZE_BYTES / 128 * i + i%4, data);
+      end
+    end
+  endtask
+
+  task direct_write_test();
+    for(int i = 0; i < 128; i++) begin
+      write_request(i, $urandom(), '1);
+    end
+    if(DATA_MEM_SIZE_BYTES > 128) begin
+      for(int i = 1; i <= 128; i++) begin
+        write_request(DATA_MEM_SIZE_BYTES / 128 * i + i%4, $urandom(), i%16);
+      end
+    end
+  endtask
+
+  task random_write_test();
+    repeat(1000) begin
+      write_request($urandom_range(0, DATA_MEM_SIZE_BYTES-1), $urandom(), $urandom_range(0, 15));
+    end
+    repeat(1000) begin
+      write_request($urandom(), $urandom(), $urandom_range(0, 15));
+    end
+  endtask
+
+  task random_read_test();
+    logic [31:0] data;
+    repeat(1000) begin
+      read_request($urandom_range(0, DATA_MEM_SIZE_BYTES-1), data);
+    end
+    repeat(1000) begin
+      read_request($urandom(), data);
+    end
+  endtask
+
+  task incorrect_read_test();
+    mem_req_i       <= '0;
+    write_enable_i  <= '1;
+    addr_i          <= '0;
+    @(posedge clk_i);
+    write_enable_i <= '0;
+    @(posedge clk_i);
+    mem_req_i <= '1;
+    @(posedge clk_i);
+  endtask
+
+  task incorrect_write_test();
+    mem_req_i       <= '0;
+    write_enable_i  <= '0;
+    byte_enable_i   <= '0;
+    write_data_i    <= '1;
+    addr_i          <= '0;
+    @(posedge clk_i);
+    mem_req_i       <= '1;
+    @(posedge clk_i);
+    write_enable_i  <= '1;
+    @(posedge clk_i);
+    byte_enable_i   <= 4'b0010;
+    @(posedge clk_i);
+  endtask
+
+  task random_test();
+    repeat(1000) begin
+      mem_req_i       <= $urandom_range(1);
+      write_enable_i  <= $urandom_range(1);
+      byte_enable_i   <= $urandom_range(15);
+      addr_i          <= $urandom();
+      write_data_i    <= $urandom();
+      @(posedge clk_i);
+    end
+  endtask
+
+  initial begin
+    $timeformat(-9, 3, "ns", 8);
+    $display("Test has been started");
+
+    DUT.ram[0] = '0;
+    DUT.ram[DATA_MEM_SIZE_WORDS-1] = '0;
+    DUT.ram[DATA_MEM_SIZE_WORDS] = '0;
+    assert( DUT.ram[0] == 0) else begin
+      $display("RAM has no element with index 0");
+      $fatal;
+    end
+    assert( DUT.ram[DATA_MEM_SIZE_WORDS-1] == 0) else begin
+      $display("RAM has no element with index %d", DATA_MEM_SIZE_WORDS-1);
+      $fatal;
+    end
+    assert( DUT.ram[DATA_MEM_SIZE_WORDS] === 'x) else begin
+      $display("RAM has element with index %d", DATA_MEM_SIZE_WORDS);
+      $fatal;
+    end
+    assert( DUT.ram[0][0] == 0) else begin
+      $display("RAM bit indexes started not from 0");
+      $fatal;
+    end
+    assert( DUT.ram[0][31] == 0) else begin
+      $display("RAM bit indexes ended not at 31");
+      $fatal;
+    end
+    assert( DUT.ram[0][32] === 'x) else begin
+      $display("RAM bit indexes ended not at 31");
+      $fatal;
+    end
+
+    direct_write_test();
+    direct_read_test();
+    random_write_test();
+    random_read_test();
+    incorrect_read_test();
+    incorrect_write_test();
+    random_test();
+
+    $display("\nTest has been finished\nNumber of errors: %d\n", err_cnt);
+    simulation_finished = 1;
+    $finish;
+  end
+
+  logic [31:0] ram_data;
+  logic [31:0] addr_reg;
+  always @(posedge clk_i) begin
+    addr_reg <= addr;
+  end
+  assign ram_data = DUT.ram[addr_reg];
+
+
+  initial begin
+    clk_i = 0;
+    forever #5 clk_i = ~clk_i;
+  end
+
+  ready_check: assert property (@(posedge clk_i) ready_o) else begin
+    err_cnt++;
+    $display("Error at %t. Value of ready is not equal 1.", $time);
+  end
+
+  correct_read_check: assert property (
+    @(posedge clk_i)
+    mem_req_i & !write_enable_i |=> read_data_o === ram_data
+  ) else begin
+    err_cnt++;
+    $display("Error at %t. Incorrect read_data_o: %08h instead of %08h", $time(), $sampled(read_data_o), $sampled(ram_data));
+  end
+
+  logic [31:0] write_data;
+  always @(posedge clk_i) begin
+    write_data <= write_data_i;
+  end
+
+  correct_write_check_0: assert property (
+    @(posedge clk_i)
+    mem_req_i & write_enable_i & byte_enable_i[0]|=> $past(write_data_i[7:0]) === ram_data[7:0]
+  ) else begin
+    err_cnt++;
+    $display("Error at %t. Incorrect value of ram[%01d][7:0]: %02h instead of %02h", $time(), $sampled(addr_reg), $sampled(ram_data[7:0]), $sampled(write_data_i[7:0]));
+  end
+  correct_write_check_1: assert property (
+    @(posedge clk_i)
+    mem_req_i & write_enable_i & byte_enable_i[1]|=> $past(write_data_i[15:8]) == ram_data[15:8]
+  ) else begin
+    err_cnt++;
+    $display("Error at %t. Incorrect value of ram[%01d][15:8]: %02h instead of %02h", $time(), $sampled(addr_reg), $sampled(ram_data[15:8]), $sampled(write_data_i[15:8]));
+  end
+  correct_write_check_2: assert property (
+    @(posedge clk_i)
+    mem_req_i & write_enable_i & byte_enable_i[2]|=> $past(write_data_i[23:16]) == ram_data[23:16]
+  ) else begin
+    err_cnt++;
+    $display("Error at %t. Incorrect value of ram[%d][23:16]: %02h instead of %02h", $time(), $sampled(addr_reg), $sampled(ram_data[23:16]), $sampled(write_data_i[23:16]));
+  end
+  correct_write_check_3: assert property (
+    @(posedge clk_i)
+    mem_req_i & write_enable_i & byte_enable_i[3]|=> $past(write_data_i[31:24]) == ram_data[31:24]
+  ) else begin
+    err_cnt++;
+    $display("Error at %t. Incorrect value of ram[%d][31:24]: %02h instead of %02h", $time(), $sampled(addr), $sampled(ram_data[31:24]), $sampled(write_data_i[31:24]));
+  end
+
+  incorrect_read_check: assert property (
+    @(posedge clk_i)
+    !mem_req_i | write_enable_i |=> $stable(read_data_o)
+  ) else begin
+    err_cnt++;
+    $display("Error at %t. read_data_o is unstable without read request", $time());
+  end
+
+  incorrect_write_check_0: assert property (
+    @(posedge clk_i)
+    (!mem_req_i | !write_enable_i | !byte_enable_i[0]) & $stable(addr) |=> $stable(ram_data[7:0])
+  ) else begin
+    err_cnt++;
+    $display("Error at %t. ram[%d][7:0] is unstable without write request", $time(), $sampled(addr_reg));
+  end
+  icorrect_write_check_1: assert property (
+    @(posedge clk_i)
+    (!mem_req_i | !write_enable_i | !byte_enable_i[1]) & $stable(addr) |=> $stable(ram_data[15:8])
+  ) else begin
+    err_cnt++;
+    $display("Error at %t. ram[%d][15:8] is unstable without write request", $time(), $sampled(addr_reg));
+  end
+  incorrect_write_check_2: assert property (
+    @(posedge clk_i)
+    (!mem_req_i | !write_enable_i | !byte_enable_i[2]) & $stable(addr) |=> $stable(ram_data[23:16])
+  ) else begin
+    err_cnt++;
+    $display("Error at %t. ram[%d][23:16] is unstable without write request", $time(), $sampled(addr_reg));
+  end
+
+  incorrect_write_check_3: assert property (
+    @(posedge clk_i)
+    (!mem_req_i | !write_enable_i | !byte_enable_i[3]) & $stable(addr) |=> $stable(ram_data[31:24])
+  ) else begin
+    err_cnt++;
+    $display("Error at %t. ram[%d][31:24] is unstable without write request", $time(), $sampled(addr_reg));
+  end
+
+
+  always @(posedge clk_i) begin
+    if(simulation_finished) begin
+      $finish;
+    end
+  end
+
+  always @(posedge clk_i) begin
+    if (err_cnt >= 10) begin
+      $display("\nTest has been stopped after 10 errors"); $stop();
+    end
+  end
+
+endmodule