diff --git a/src/jlink.cpp b/src/jlink.cpp
index 29d2236..0ba9a8e 100644
--- a/src/jlink.cpp
+++ b/src/jlink.cpp
@@ -192,6 +192,46 @@ int Jlink::flush()
 	return ll_write(NULL);
 }
 
+bool Jlink::writeTMSTDI(const uint8_t *tms, const uint8_t *tdi, uint8_t *tdo,
+		uint32_t numbits)
+{
+	// use pointer to access all vectors
+	const uint8_t *tms_ptr = tms;
+	const uint8_t *tdi_ptr = tdi;
+	uint8_t *tdo_ptr = tdo;
+
+	uint32_t xfer_len = 0;
+
+	while (numbits > 0) {
+		// if bits to send are greater than internal buffer
+		// limits to buffer size
+		if (numbits > (BUF_SIZE * 8))
+			xfer_len = BUF_SIZE * 8;
+		else  // or direct xfer
+			xfer_len = numbits;
+		// convert size in Byte
+		uint16_t numbytes = (xfer_len + 7) >> 8;
+
+		// copy buffers to internals
+		memcpy(_tms, tms_ptr, numbytes);
+		memcpy(_tdi, tdi_ptr, numbytes);
+		// save size to transmit
+		_num_bits = xfer_len;
+		// send
+		if (!ll_write(tdo_ptr))
+			return false;
+		// decrement bits to send
+		numbits -= xfer_len;
+		// move pointers
+		tms_ptr += numbytes;
+		tdi_ptr += numbytes;
+		if (tdo)
+			tdo_ptr += numbytes;
+	}
+
+	return true;
+}
+
 bool Jlink::ll_write(uint8_t *tdo)
 {
 	if (_num_bits == 0)
@@ -576,19 +616,6 @@ void Jlink::read_config()
 	}
 }
 
-bool Jlink::write_data(const uint8_t *tms, const uint8_t *tdi, uint8_t *tdo,
-		uint16_t numbits)
-{
-	if (numbits > (BUF_SIZE * 8))
-		numbits = BUF_SIZE * 8;
-	uint16_t numbytes = (numbits +7) >> 8;
-
-	memcpy(_tms, tms, numbytes);
-	memcpy(_tdi, tdi, numbytes);
-	_num_bits = numbits;
-	return ll_write(tdo);
-}
-
 bool Jlink::jlink_search_interface(libusb_device *dev,
 		libusb_device_descriptor *desc, int *interface_idx,
 		int *config_idx, int *alt_idx)
diff --git a/src/jlink.hpp b/src/jlink.hpp
index c2710f4..7415d1b 100644
--- a/src/jlink.hpp
+++ b/src/jlink.hpp
@@ -56,6 +56,17 @@ class Jlink: public JtagInterface {
 		 */
 		int writeTDI(uint8_t *tx, uint8_t *rx, uint32_t len, bool end) override;
 
+		/*!
+		 * \brief access ll_write outer this class / directly receives
+		 *        fully filled tms, tdi buffers, and optionnally tdo
+		 * \param[in] tms: tms buffer
+		 * \param[in] tdi: tdi buffer
+		 * \param[out] tdo: tdo buffer
+		 * \param[in] numbits: tms/tdi/tdo buffer size (in bit)
+		 */
+		bool writeTMSTDI(const uint8_t *tms, const uint8_t *tdi, uint8_t *tdo,
+				uint32_t numbits);
+
 		/*!
 		 * \brief send a serie of clock cycle with constant TMS and TDI
 		 * \param[in] tms: tms state
@@ -88,16 +99,6 @@ class Jlink: public JtagInterface {
 		bool get_result();
 		bool max_mem_block(uint32_t *max_mem);
 
-		/*!
-		 * \brief test method to access ll_write outer this class
-		 * \param[in] tms: tms buffer
-		 * \param[in] tdi: tdi buffer
-		 * \param[out] tdo: tdo buffer
-		 * \param[in] numbits: tms/tdi/tdo buffer size (in bit)
-		 */
-		bool write_data(const uint8_t *tms, const uint8_t *tdi, uint8_t *tdo,
-				uint16_t numbits);
-
 	private:
 		// Jlink EMU_CMD code
 		enum {