diff --git a/libs/libpcf/src/io/read_csv_io_pin_table.cpp b/libs/libpcf/src/io/read_csv_io_pin_table.cpp
index 18bc0499c..0a1e90d9c 100644
--- a/libs/libpcf/src/io/read_csv_io_pin_table.cpp
+++ b/libs/libpcf/src/io/read_csv_io_pin_table.cpp
@@ -18,6 +18,14 @@
 /* Begin namespace openfpga */
 namespace openfpga {
 
+/* Constants for io pin table csv parser */
+constexpr const int ROW_INDEX_INTERNAL_PIN = 4;
+constexpr const int ROW_INDEX_EXTERNAL_PIN = 5; 
+constexpr const int ROW_INDEX_DIRECTION = 6; 
+constexpr const int ROW_INDEX_SIDE = 0; 
+constexpr const char* DIRECTION_INPUT = "in";
+constexpr const char* DIRECTION_OUTPUT = "out";
+
 /********************************************************************
  * Parse XML codes about <pin_constraints> to an object of PinConstraints
  *******************************************************************/
@@ -40,13 +48,13 @@ IoPinTable read_csv_io_pin_table(const char* fname) {
     std::vector<std::string> row_vec = doc.GetRow<std::string>(irow);
     IoPinTableId pin_id = io_pin_table.create_pin();
     /* Fill pin-level information */
-    PortParser internal_pin_parser(row_vec.at(4));
+    PortParser internal_pin_parser(row_vec.at(ROW_INDEX_INTERNAL_PIN));
     io_pin_table.set_internal_pin(pin_id, internal_pin_parser.port());
 
-    PortParser external_pin_parser(row_vec.at(5));
+    PortParser external_pin_parser(row_vec.at(ROW_INDEX_EXTERNAL_PIN));
     io_pin_table.set_external_pin(pin_id, external_pin_parser.port());
 
-    std::string pin_side_str = row_vec.at(0);
+    std::string pin_side_str = row_vec.at(ROW_INDEX_SIDE);
     if (side_str_map.end() == side_str_map.find(pin_side_str)) {
       VTR_LOG(
         "Invalid side defintion (='%s')! Expect [TOP|RIGHT|LEFT|BOTTOM]\n",
@@ -69,6 +77,18 @@ IoPinTable read_csv_io_pin_table(const char* fname) {
         "Invalid direction defintion! Expect [A2F|F2A] in the pin name\n");
       exit(1);
     }
+
+    /* Parse pin direction from a specific column, this has a higher priority than inferring from pin names */
+    std::string port_dir_str = row_vec.at(ROW_INDEX_DIRECTION);
+    if (port_dir_str == std::string(DIRECTION_INPUT)) {
+      io_pin_table.set_pin_direction(pin_id, IoPinTable::INPUT);
+    } else if (port_dir_str == std::string(DIRECTION_OUTPUT)) {
+      io_pin_table.set_pin_direction(pin_id, IoPinTable::OUTPUT);
+    } else {
+      VTR_LOG(
+        "Invalid direction defintion! Expect [%s|%s] in the GPIO direction\n", DIRECTION_INPUT, DIRECTION_OUTPUT);
+      exit(1);
+    }
   }
 
   return io_pin_table;