Chapter 6 Input/Output

Chapter 6 Input/Output

1. External devices/peripheral devices

   • Machine reable
   • human reable
   • communication

2. Transducer

   • - Convert data from electrical to other forms of energy.
   • I/O Module Categories
     • Control and Timing
     • Processor Communication
     • Device Communication
     • Data Buffering
     • Error Detection

3. Techniques for I/O

   • Programmed I/O
     • - CPU checks status bits periodically - Lots of CPU time wasted - inefficient CPU usage - I/O module does not inform
   • Interrupt-driven I/O
     • - I/O module interrupt CPU it is ready.
   • Direct memory access (DMA)
     • - CMA controller takes over the task from CPU for I/O operation.

4. I/O commands

   • Control
   • Test
   • Read
   • Write

5. I/O Mapping summary

   • Isolated I/O
     • - Separate address space
   • Memory mapped I/O
     • - I/O device and memory share an address space

6. FireWire Serial Bus

   • - IEEE standard 1394, High Performance Serial Bus

7. Device Identification

   • - Multiple interrupt lines  - Software poll - Daisy chain (hard poll, vectored) - Bus arbitration (vectored)

8. Universal Serial Bus (USB)

   • - Widely used for peripheral connections - Commonly used high-speed I/O