The pin test buffer inputs {TAIL ~ external inputs} to a pin, and outputs to the same pin from {HEAD ~ the device} 
The pin test buffer inputs { TAIL ~ external inputs } to a pin , and outputs to the same pin from { HEAD ~ the device }
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD