Chapter 6 Input/Output

Chapter 6 Input/Output

1. External Devices

   • Human readable
   • Machine readable
   • Communication

2. Keyboard/Monitor

   • International Reference Alphabet (IRA)
   • Keyboard Codes

3. Major function for an I/O module

   • COntrol and timing
   • Processor communication
   • Device communication
   • Data buffering
   • Error detection

4. 3 techniques are possible for I/O operation

   • Programmed I/O
   • Direct memory access (DMA)
   • Interrupt-driven I/O

5. I/O Commands

   • Control
   • Test
   • Read
   • Write

6. I/O Instruction

7. I/O Mapping Summary

   • Isolated I/O
   • Memory mapped I/O

8. Interrupt-Driven I/O

9. Device Identification

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

10. Drawback of Programmed and Interrupt-Driven I/O

    • I/O transfer limited by the speed of processor
    • processor is tied up in managing an I/O transfer

11. Evolution of the I/O Function

12. Universal Serial Bus (USB)

13. FireWire Serial Bus