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Basic Bus: One initiator (II).

The most basic bus has one initiator and several targets. The initiator does not need to arbitrate for the bus since it has no competitors.

Bus operations are reads or writes. In reality, most on-chip busses support burst transactions, whereby multiple consecutive reads or writes can be performed as a single transaction with subsequent addresses being implied as offsets from the first address.

Interrupt signals are not shown in these figures. In a SoC they do not need to be part of the physical bus as such: they can just be dedicated wires running from device to device. (For ESL higher-level models and IP-XACT representation, interrupts need management in terms of allocation and naming in the same way as the data resources.)

Un-buffered wiring can potentially serve for the write and address busses, whereas multiplexors are needed for read data. Buffering is needed in all directions for busses that go a long way over the chip.

3: (C) 2008-11, DJ Greaves, University of Cambridge, Computer Laboratory.