diff -r 55021f3f1929 -r e5254c6aa0c8 src/hp34comm.cpp
--- a/src/hp34comm.cpp	Tue Oct 11 00:14:20 2016 +0200
+++ b/src/hp34comm.cpp	Tue Oct 11 00:46:18 2016 +0200
@@ -17,7 +17,6 @@
 DigitalOut lled(LED1);
   
 HPSerial::HPSerial(PinName rx, PinName tx):
-  serial_tx(A7, tx),
   serial_rx(NC, rx),
   ncmd(0) {
   
@@ -27,9 +26,6 @@
     errs[i] = 0;
   reset();
   
-  serial_tx.baud(187500);
-  serial_tx.attach(this, &HPSerial::txIrq, Serial::RxIrq); //sic!
-  
   serial_rx.baud(187500);
   serial_rx.attach(this, &HPSerial::rxIrq, Serial::RxIrq);
 }
@@ -74,40 +70,35 @@
     tx_state = Tx;
     setstatedbg();
   } else
-    
-    if (tx_ack == true)
-      reset(0);
-  
-    else
-      if (tx_cmd == 0xFF) // still at the beginning of a packet, expect 0x99 as ack
-	if (val == 0x99)
-	  {
-	    tx_ack = true;
+    if (tx_cmd == 0xFF) // beginning of a packet, expect 0x99 as ack
+      if (val == 0x99)
+	{
+	  tx_ack = true;
 #ifdef DEBUG2
-	    ack = 1;
-	    wait_us(2);
-	    ack = 0;
+	  ack = 1;
+	  wait_us(2);
+	  ack = 0;
 #endif
-	  }
-	else 
-	  reset(1);
+	}
+      else 
+	reset(1);
 
-      else // expect 0x00 as ack
-	if (val == 0x00)
-	  {
-	    tx_ack = true;
+    else // expect 0x00 as ack
+      if (val == 0x00)
+	{
+	  tx_ack = true;
 #ifdef DEBUG2
-	    ack = 1;
-	    wait_us(2);
-	    ack = 0;
-	    wait_us(2);
-	    ack = 1;
-	    wait_us(2);
-	    ack = 0;
+	  ack = 1;
+	  wait_us(2);
+	  ack = 0;
+	  wait_us(2);
+	  ack = 1;
+	  wait_us(2);
+	  ack = 0;
 #endif
-	  }
-	else
-	  reset(2);
+	}
+      else
+	reset(2);
 }
 
 void HPSerial::pushCmd(TrState direction, uint8_t cmd, uint8_t size, char *payload) {
@@ -131,16 +122,19 @@
       // begin of transmission, expect a cmd
       tx_cmd = val;
       tx_ack = false;
-      if (tx_state == Rx)
-	tx_len = 0xFF;
-      else
-	tx_len = 0x00; // no payload: tx_cmd is the key stroke
+      tx_len = 0xFF;
     }
     else if (tx_len == 0xFF) {
       // got a cmd, expect a payload size
       tx_len = val;
       tx_ack = false;
     }
+    else if (tx_len == 0x55) {
+      // packet was in fact a keystroke, tx_cmd is in fact the key
+      // stroke and no payload is expected 
+      pushCmd((TrState)Tx, tx_cmd, 0, NULL);
+      reset();
+    }
     else if (tx_len > 0) {
       // a payload char
       buf[head++] = val;
@@ -188,7 +182,7 @@
 #ifdef DEBUG2
     inrx=1;
 #endif
-  lled = 1;
+    lled = 1;
     val = serial_rx.getc();
     
     timeouter.attach(this, &HPSerial::timeout, 0.001); // if nothing else happen in the next ms, reset
@@ -203,49 +197,17 @@
       else {
 	reset(4);
       }
-    else if (tx_state == Tx)  // manage the acks
+    else if (tx_ack == false)  // manage the acks
       handleAck(val);
-    
     else 
       handleChar(val);
-  lled = 0;
+    lled = 0;
 #ifdef DEBUG2
     inrx=0;
 #endif
   }
 }
 
-void HPSerial::txIrq(void) {
-  uint8_t val;
-  if(serial_tx.readable()) { // no reason why we would end here without this condition, but hey
-#ifdef DEBUG2
-    intx=1;
-#endif
-    val = serial_tx.getc();
-    
-    timeouter.attach(this, &HPSerial::timeout, 0.001); // if nothing else happen in the next ms, reset
-    
-    if (tx_state == Idle)
-      if (val == 0x66) {
-	// no transmission in progress, expect a start of transmission
-	tx_state = Tx;
-	tx_ack = false;
-	setstatedbg();
-      }
-      else {
-	reset(5);
-      }
-    
-    else if (tx_state == Rx)  // manage the acks
-      handleAck(val);
-    
-    else 
-      handleChar(val);
-  }
-#ifdef DEBUG2
-  intx=0;
-#endif
-}
 
 void HPSerial::timeout(void) {
   if (tx_state != Idle) {