diff --git a/src/jtag.cpp b/src/jtag.cpp
index 2f14969..c7ed49e 100644
--- a/src/jtag.cpp
+++ b/src/jtag.cpp
@@ -371,11 +371,11 @@ int Jtag::read_write(const uint8_t *tdi, unsigned char *tdo, int len, char last)
 	return 0;
 }
 
-void Jtag::toggleClk(int nb)
+void Jtag::toggleClk(int nb, uint8_t tdi)
 {
 	unsigned char c = (TEST_LOGIC_RESET == _state) ? 1 : 0;
 	flushTMS(false);
-	if (_jtag->toggleClk(c, 0, nb) >= 0)
+	if (_jtag->toggleClk(c, tdi, nb) >= 0)
 		return;
 	throw std::exception();
 	return;
diff --git a/src/jtag.hpp b/src/jtag.hpp
index c2f5f58..15fdfee 100644
--- a/src/jtag.hpp
+++ b/src/jtag.hpp
@@ -133,7 +133,7 @@ class Jtag {
 		tapState_t end_state = RUN_TEST_IDLE);
 	int read_write(const uint8_t *tdi, unsigned char *tdo, int len, char last);
 
-	void toggleClk(int nb);
+	void toggleClk(int nb, uint8_t tdi = 0);
 	void go_test_logic_reset();
 	void set_state(tapState_t newState, const uint8_t tdi = 1);
 	int flushTMS(bool flush_buffer = false);