diff --git a/hdl/tb/core_tb.v b/hdl/tb/core_tb.v
index 233de23..8831b91 100644
--- a/hdl/tb/core_tb.v
+++ b/hdl/tb/core_tb.v
@@ -48,9 +48,10 @@ wire [31:0] mem_data_wdata;
 wire [3:0] mem_data_wmask;
 wire mem_data_we;
 reg mem_data_wready;
-wire mem_data_rvalid = 1'b1;
+reg mem_data_rvalid;
 
-always @(*) begin
+always @(mem_data_addr) begin    
+    mem_data_rvalid = 1'b1;
     if (mem_data_addr < MEM_LENGTH - 3) begin
         mem_data_rdata[ 7: 0] = mem[mem_data_addr+0];
         if (mem_data_addr[0] == 0) begin