RapidIO: The Next Generation Communication Fabric For Embedded Application

3.2. I/O PROCESSING ELEMENT

This type of processing element is shown as the bridge in Figure 3.1. This device has distinctly different behavior than a processor or a memory device. An I/O processing element converts RapidIO transactions into other I/O transactions such as PCI or Ethernet. This conversion is typically a very straightforward operation as the I/O peripheral or I/O bus element typically will present itself to the system as a set of memory mapped registers and a range of read/write memory addresses. One of RapidIO's core objectives is to appear as a software transparent interconnect to I/O peripheral devices. The RapidIO Trade Association has created an inter-operability specification that details how RapidIO devices should interoperate not only with each other but with other technologies like PCI as well. A discussion of this topic appears in Chapter 9.