An AMBA AHB couples {HEAD ~ the cores} and most other functional units on {TAIL ~ the IC} 
An AMBA AHB couples { HEAD ~ the cores } and most other functional units on { TAIL ~ the IC }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL