diff --git a/openfpga_flow/VerilogNetlists/gpio.v b/openfpga_flow/VerilogNetlists/gpio.v
new file mode 100644
index 000000000..5fb318f3d
--- /dev/null
+++ b/openfpga_flow/VerilogNetlists/gpio.v
@@ -0,0 +1,20 @@
+//-----------------------------------------------------
+// Design Name : General Purpose I/Os
+// File Name   : gpio.v
+// Coder       : Xifan TANG
+//-----------------------------------------------------
+
+//-----------------------------------------------------
+// Function    : A minimum general purpose I/O
+//-----------------------------------------------------
+module GPIO (
+  input A, // Data output
+  output Y, // Data input
+  inout PAD, // bi-directional pad
+  input DIR // direction control
+);
+  //----- when direction enabled, the signal is propagated from PAD to data input
+  assign Y = DIR ? PAD : 1'bz;
+  //----- when direction is disabled, the signal is propagated from data out to pad
+  assign PAD = DIR ? 1'bz : A;
+endmodule