A hand shake type control circuit for controlling a data transfer circuit according to {HEAD ~ the status} of {TAIL ~ a data transfer request signal} 
A hand shake type control circuit for controlling a data transfer circuit according to { HEAD ~ the status } of { TAIL ~ a data transfer request signal }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL