diff --git a/hardware0.hpp b/hardware0.hpp
index 16e6fff..81aa614 100644
--- a/hardware0.hpp
+++ b/hardware0.hpp
@@ -12,11 +12,16 @@ enum class Mode {
 	SPI,
 };
 
-template <Mode mode, class config>
+enum class Driven {
+	INTERRUPT,
+	BLOCKING,
+};
+
+template <Mode mode, class cfg = config<>, Driven driven = Driven::INTERRUPT>
 class hardware0 {
   public:
-	using data_t = typename config::data_t;
-	static constexpr auto DATA_BITS = config::DATA_BITS;
+	using data_t = typename cfg::data_t;
+	static constexpr auto DATA_BITS = cfg::DATA_BITS;
 
 	static void init() {}
 
@@ -30,9 +35,9 @@ class hardware0 {
 	static data_t peek() {}
 
   private:
-	static constexpr auto BAUD_RATE = config::BAUD_RATE;
-	static constexpr auto PARITY = config::PARITY;
-	static constexpr auto STOP_BITS = config::STOP_BITS;
+	static constexpr auto BAUD_RATE = cfg::BAUD_RATE;
+	static constexpr auto PARITY = cfg::PARITY;
+	static constexpr auto STOP_BITS = cfg::STOP_BITS;
 };
 
 } // namespace uart