diff -r 219766126afb -r f1c85c2500f2 src/hp34comm.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hp34comm.h	Tue Sep 20 23:50:45 2016 +0200
@@ -0,0 +1,65 @@
+#ifndef HP34COMM_H
+#define HP34COMM_H
+
+#include "mbed.h"
+#include "CircularBuffer.h"
+
+/***** HP 34970A communication class ***/
+
+#define MAX_ERRS 10
+#define MAX_BUFF 32
+#define BUF_SIZE 32
+
+class HPSerial {
+
+public:
+  enum TrState {
+        Idle = 0,
+        Tx,
+        Rx,
+    };
+  typedef struct _CMD
+  {
+    TrState direction;
+    uint8_t cmd;
+    uint8_t size;
+    char value[MAX_BUFF+1];
+    unsigned long id;
+  } CMD;
+
+
+  
+  HPSerial();
+  
+  bool cmd_available(void);
+  bool pop(CMD& cmd);
+  bool cmd_buf_full(void);
+  unsigned int nerrors(uint8_t errorno);
+		     
+  
+private:
+  void reset(uint8_t errorno=0xFF);
+  void handleAck(uint8_t val);
+  void pushCmd(TrState direction, uint8_t cmd, uint8_t size, char *payload);
+  void handleChar(uint8_t val);
+  void setstatedbg(void);    
+  void rxIrq(void);
+  void txIrq(void);
+  void timeout(void);
+
+ private:
+  RawSerial serial_tx;
+  RawSerial serial_rx;
+  uint8_t buf[BUF_SIZE];
+  uint8_t head;
+  uint8_t tx_state;
+  uint8_t tx_cmd;
+  uint8_t tx_len;
+  bool tx_ack;
+  CircularBuffer<CMD, 32> cmdbuf;
+  unsigned long ncmd;
+  unsigned int errs[MAX_ERRS];
+  Ticker timeouter;
+};
+
+#endif