Connecting Multiple Peripheral IO Devices
Typically in an FPGA design, the processor will need to interface to multiple peripheral I/O devices, many of which are interfacing controllers for communicating with external devices or circuitry. Each of these peripherals may contain any number of internal registers with which to write to/read from. It is not possible to communicate directly, and simultaneously, with each of these slave devices. A means of multiplexing must be used, allowing the processor to talk to any number of slaves over the one bus interface. Again, this can be achieved using an Interconnect component within the OpenBus System.
In the example system of Figure 1, the Interconnect component enables a single 32-bit processor (MicroBlaze) to communicate with three peripheral I/O devices (a Parallel Port Unit, a PS2 Controller and a 32-bit Ethernet Media Access Controller).
Figure 1. Multiplexing a processor's peripheral I/O interface using an Interconnect component.