diff --git a/litex/build/generic_platform.py b/litex/build/generic_platform.py
index 1e160589f..f79b7f5d6 100644
--- a/litex/build/generic_platform.py
+++ b/litex/build/generic_platform.py
@@ -167,7 +167,12 @@ class ConnectorManager:
                     raise ValueError(f"\"{identifier}\" {err}") from err
                 if pn.isdigit():
                     pn = int(pn)
-
+                assert conn in self.connector_table, f"No connector named '{conn}' is available"
+                conn_entry = self.connector_table[conn]
+                if isinstance(conn_entry, dict):
+                    assert pn in conn_entry, f"There is no pin '{pn}' on connector '{conn}'"
+                else:
+                    assert pn < len(conn_entry), f"There is no pin with number '{pn}' on connector '{conn}', maximum is {len(conn_entry)-1}"
                 conn_pn = self.connector_table[conn][pn]
                 if ":" in conn_pn:
                     conn_pn = self.resolve_identifiers([conn_pn])[0]