diff --git a/driver/drv/b15f.cpp b/driver/drv/b15f.cpp
index f53d066..fc3f804 100644
--- a/driver/drv/b15f.cpp
+++ b/driver/drv/b15f.cpp
@@ -30,7 +30,10 @@ void B15F::init()
 	 // Temporärer Test
 	uint8_t block[] = {0, 1, 2, 3};
 	while(1)
+	{
 		usart.writeBlock(&block[0], 0, sizeof(block));
+		usart.printStatistics();
+	}
 	throw std::runtime_error("SCHLUSS");
 	
 	
@@ -83,13 +86,13 @@ void B15F::reconnect()
 
 void B15F::discard(void)
 {
-	usart.flushOutputBuffer();
+	usart.clearOutputBuffer();
 	for(uint8_t i = 0; i < 8; i++)
 	{
 		usart.writeByte(RQ_DISC);	// sende discard Befehl (verwerfe input)
 		delay_ms((16000 / BAUDRATE) + 1); // warte mindestens eine Millisekunde, gegebenenfalls mehr
 	}
-	usart.flushInputBuffer();
+	usart.clearInputBuffer();
 }
 
 bool B15F::testConnection()
@@ -147,7 +150,7 @@ std::vector<std::string> B15F::getBoardInfo(void)
 
 bool B15F::digitalWrite0(uint8_t port)
 {
-	usart.flushInputBuffer();
+	usart.clearInputBuffer();
 	usart.writeByte(RQ_BA0);
 	usart.writeByte(port);
 	
@@ -157,7 +160,7 @@ bool B15F::digitalWrite0(uint8_t port)
 
 bool B15F::digitalWrite1(uint8_t port)
 {
-	usart.flushInputBuffer();
+	usart.clearInputBuffer();
 	usart.writeByte(RQ_BA1);
 	usart.writeByte(port);
 	
@@ -167,21 +170,21 @@ bool B15F::digitalWrite1(uint8_t port)
 
 uint8_t B15F::digitalRead0()
 {
-	usart.flushInputBuffer();
+	usart.clearInputBuffer();
 	usart.writeByte(RQ_BE0);
 	return usart.readByte();
 }
 
 uint8_t B15F::digitalRead1()
 {
-	usart.flushInputBuffer();
+	usart.clearInputBuffer();
 	usart.writeByte(RQ_BE1);
 	return usart.readByte();
 }
 
 bool B15F::analogWrite0(uint16_t value)
 {
-	usart.flushInputBuffer();
+	usart.clearInputBuffer();
 	usart.writeByte(RQ_AA0);
 	usart.writeInt(value);
 	
@@ -191,7 +194,7 @@ bool B15F::analogWrite0(uint16_t value)
 
 bool B15F::analogWrite1(uint16_t value)
 {
-	usart.flushInputBuffer();
+	usart.clearInputBuffer();
 	usart.writeByte(RQ_AA1);
 	usart.writeInt(value);
 	
@@ -201,7 +204,7 @@ bool B15F::analogWrite1(uint16_t value)
 
 uint16_t B15F::analogRead(uint8_t channel)
 {
-	usart.flushInputBuffer();
+	usart.clearInputBuffer();
 	usart.writeByte(RQ_ADC);
 	usart.writeByte(channel);
 	return usart.readInt();
@@ -212,7 +215,7 @@ bool B15F::analogSequence(uint8_t channel_a, uint16_t* buffer_a, uint32_t offset
 	buffer_a += offset_a;
 	buffer_b += offset_b;
 	
-	usart.flushInputBuffer();
+	usart.clearInputBuffer();
 	usart.writeByte(RQ_ADC_DAC_STROKE);
 	usart.writeByte(channel_a);
 	usart.writeByte(channel_b);
diff --git a/driver/drv/b15f.o b/driver/drv/b15f.o
index 0bd67cc..79f3e7b 100644
Binary files a/driver/drv/b15f.o and b/driver/drv/b15f.o differ
diff --git a/driver/drv/usart.cpp b/driver/drv/usart.cpp
index d2e8bdd..1516c59 100644
--- a/driver/drv/usart.cpp
+++ b/driver/drv/usart.cpp
@@ -25,8 +25,8 @@ void USART::openDevice(std::string device)
 	if(code)
 		throw USARTException("Fehler beim Setzen der Geräteparameter");
 	
-	flushOutputBuffer();
-	flushInputBuffer();
+	clearOutputBuffer();
+	clearInputBuffer();
 }
 	
 void USART::closeDevice()
@@ -36,20 +36,27 @@ void USART::closeDevice()
 		throw USARTException("Fehler beim Schließen des Gerätes");
 }
 	
-void USART::flushInputBuffer()
+void USART::clearInputBuffer()
 {
 	int code = tcflush(file_desc, TCIFLUSH);
 	if(code)
 		throw USARTException("Fehler beim Leeren des Eingangspuffers");
 }
 	
-void USART::flushOutputBuffer()
+void USART::clearOutputBuffer()
 {
 	int code = tcflush(file_desc, TCOFLUSH);
 	if(code)
 		throw USARTException("Fehler beim Leeren des Ausgangspuffers");
 }
 
+void USART::printStatistics()
+{
+	double pz = 1e2 * n_blocks_failed / n_blocks_total;
+	pz = std::round(pz * 1e2) / 1e2;
+	std::cout << "blocks total: " << n_blocks_total << "   ok: " << (n_blocks_total - n_blocks_failed) << "   failed: " << n_blocks_failed << " (" << pz << "%)" << std::endl;
+}
+
 void USART::writeByte(uint8_t b)
 {
 	int sent = write(file_desc, &b, 1);
@@ -118,6 +125,9 @@ void USART::writeBlock(uint8_t* buffer, uint16_t offset, uint8_t len)
 	const uint16_t us_per_bit = (1000000 / baudrate) * 16;
 	const uint16_t n_total = len + 3;
 	
+	n_blocks_total++;
+	bool failed = false;
+	
 	do
 	{	
 		// calc crc
@@ -163,10 +173,14 @@ void USART::writeBlock(uint8_t* buffer, uint16_t offset, uint8_t len)
 		if(n_read != 1)
 			throw std::runtime_error("fatal: " + std::to_string(n_read));
 	
-		//flushInputBuffer();
+		//clearInputBuffer();
 		
-		if(aw != 0xFF)
+		if(aw != 0xFF) {
+			if(!failed)
+				n_blocks_failed++;
+			failed = true;
 			std::cout << "block failed, retry" << std::endl;
+		}
 	}
 	while(aw != 0xFF);
 	
diff --git a/driver/drv/usart.h b/driver/drv/usart.h
index 006ffef..e375e8c 100644
--- a/driver/drv/usart.h
+++ b/driver/drv/usart.h
@@ -9,6 +9,7 @@
 #include <fcntl.h>
 #include <sys/ioctl.h>
 #include <termios.h>
+#include <cmath>
 #include "usartexception.h"
 #include "timeoutexception.h"
 
@@ -37,13 +38,18 @@ public:
 	 * Verwirft Daten, die bereits im Puffer liegen, aber noch nicht gelesen wurden
 	 * \throws USARTException 
 	 */
-	void flushInputBuffer(void);
+	void clearInputBuffer(void);
 	
 	/**
 	 * Verwirft Daten, die bereits im Puffer liegen, aber noch nicht gesendet wurden
 	 * \throws USARTException 
 	 */
-	void flushOutputBuffer(void);
+	void clearOutputBuffer(void);
+	
+	/**
+	 * Gibt Anzahl an erfolgreichen und fehlgeschlagenen Block-Übertragungen an
+	 */
+	void printStatistics(void);
 	
 	/*************************************************/
 	
@@ -128,6 +134,10 @@ private:
 	int TEST = 0;
 	uint8_t timeout = 10; // in Dezisekunden
 	uint8_t block_buffer[MAX_BLOCK_SIZE + 3];
+	
+	// debug statistics
+	uint32_t n_blocks_total = 0;
+	uint32_t n_blocks_failed = 0;
 };
 
 
diff --git a/driver/drv/usart.o b/driver/drv/usart.o
index ef05e38..ed30f7a 100644
Binary files a/driver/drv/usart.o and b/driver/drv/usart.o differ
diff --git a/driver/main b/driver/main
index 83512de..307f0d1 100755
Binary files a/driver/main and b/driver/main differ