anchor.diff:  
   : ep-in ( ep -- )  \ incoming polls, sent from this device to host
     dup if
  -    0 tx.pend ! usb-fill
  +    0 usb.ticks !  0 tx.pend !  usb-fill
     else
       $41 usb-pma c@ $05 = if $42 usb-pma@ $80 or USB-DADDR h! then
       send-next
  
positive.code:   $3003 3 ep-addr h!
    $80 USB-DADDR h! ;
  
  0 variable zero
  
  256 4 + buffer: usb-in-ring   \ RX ring buffer, ample for mecrisp input lines
   64 4 + buffer: usb-out-ring  \ TX ring buffer, for outbound bytes
  
negative.code:   ['] usb-emit? hook-emit? !
    ['] usb-emit hook-emit !  ;
  
  \ : init ( -- ) init usb-io ;
  