   lineLength=hexByte(cmdbuf+12);
   byte retval = 0;
   switch(cmdbuf[0]) {
+  case 'A':
+    retval = SET_ADDRESS;
+    break;
   case 'R':
     retval = READ_HEX;
     break;

//define COMMANDS
#define NOCOMMAND    0
#define VERSION      1

#define READ_HEX    10
#define READ_BIN    11

  byte cmd = parseCommand();
  int bytes = 0;
  switch(cmd) {
  case SET_ADDRESS:
    // Set the address bus to an arbitrary value.
    // Useful for debugging shift-register wiring, byte-order.
    // e.g. A,00FF
    Serial.print("Setting address bus to 0x");
    Serial.println(cmdbuf + 2);
    set_address_bus(startAddress);
    break;
  case READ_HEX:
    //set a default if needed to prevent infinite loop
    if(lineLength==0) lineLength=32;
