H/W to S/W Interfacing

The primary ways of connecting H/W to S/W are:

• Programmed I/O to pin-level PIO register,
• Programmed I/O to FIFOs,
• Interrupts (hardwired or dynamically dispatched),
• Packet channel mapped into register file,
• DMA,
• Psudo-DMA (processor generates addresses only.