Next: Polled Input/Output
Up: No Title
Previous: Device Handler
Devices can be separate or memory mapped :
Separate I/O Bus
![figure133](img7.gif)
Figure 6: separate I/O Bus
- Special assembly code procedures called by high level language
![figure138](img8.gif)
Figure 7: memory mapped I/O
- Device addressed as another memory location
- Use of high level language primitives which access memory, e.g. ch := rbuf
- More flexible
Omer F Rana
Fri Feb 14 18:33:29 GMT 1997